Eric, you need to cut off the tip (pointy part) off of the fill plug. The plug seals the gauge so that the glycerine doesn't leak during shipping. Unfortunately, if you don't create an opening by cutting off the nipple, the outside of the bourdon tube, the part that changes shape as pressure inside it changes, has no reference to atmospheric pressure which is what you're measuring fuel pressure against. If there is a pressure build up inside the gauge case for whatever reason, the needle will indicate a lower reading than if the gauge mechanism was exposed to atmospheric reference pressure. I.E, 9 psi fuel pressure will indicate as 6 psi on the dial if there is a 3 psi pressure build up inside the case. I've seen this problem many, many times in industrial applications, especially in lower pressure ranges like is the case in your application.
Aha!!!!! interesting! explains why the cheapo liq-filled gauge I used on my 91 Storm never acted up on me. I swapped out the glycerine for mineral oil because the provided expansion space was way larger than it should've been & I couldn't find glycerine with which to bring the level up to spec. I decided to push things & leave a smaller bubble for aesthetics, *installing a rubber expansion tube I dyi'd onto the gauge* . I left it open ended & *LOOSELY* packed with a bit of cotton ball to keep out contaminants. Maybe the mineral oil helped as well?
Hi Eric, if you want a "true" reading on a glycerin filled gauges, you will have to cut off the rubber tip on the fill plug on top of the gauge, this is only sealed for transportation. more expensiv guages in industry have a valve on top with clear markings for transport and opperation posittions. i have workt for many years on boats and have sen this a lot. when you heat the guage, the air and glycerine expands, and the pressure inside the gauge increases, dus causing the pressure to read lower than it actually is.
Definitely helpful Eric! I was actually diagnosing inconsistent pressure this past week on a built '17 Subaru STI. Sadly, the gauge wasn't the cause of the problem. (we mount our fprs and gauges on the strut brace usually instead of the engine. Helps a lot with vibration issues) Turned out it was an issue on the Venturi pump siphon/scavenge setup in the fuel tank. Installed a new Venturi pump and simplifies the system, and the pressure got much more consistent. Less pressure in the return line to the tank! Needless to say, there was a lot of "tail shaking" going on for us too
Man. I have been fighting with my fuel pressure for months since my build. Thanks for this. Even my Holley has a rubber plug I just released the pressure and finally it all makes sense.
Exactly what my glycerin filled gauge is doing when hot. Drops to 2 psi and adjusting the regulator does nothing. I'm putting in a non liquid filled gauge tomorrow. Thank you so much.
Jim Hand, a prominent old school Pontiac V8 builder found out the liquid filled fuel gauges aren’t accurate when mounted inside the engine compartment, due to temperature fluctuations. Jim literally just pulled the rubber plug and drained the glycerin out, problem fixed! Some times simple is better! 👍👍👍
Eric, I found the glycerin leaked out. Replaced it with an Edelbrock (Russell) non-liquid gauge. I noticed the fuel pressure increased after I shut off the engine. Needle and seat should have less than 5 psi. Shut off pressure was 6 psi. 70 Firebird stock fuel pump. I dropped the shut off pressure to 5 psi to prevent flooding.
Dammit. Just got that same guage a month back. Haven't used it yet. Nor will I. I mean it is only 20 bucks, you get what you pay for! Thanks Eric! Useful information as always!
I note the proliferation of electronic pressure gauges, these can monitor oil or fuel pressure and are in the $20 range. They do require a wire from the sensor, one for battery voltage and a ground at the sensor as the sensor might be isolated from ground as it is on my old Honda.
Eric your gauge sounds accurate. I run Fuel Pressure control. 45-100psi to be exact. It's PWM based. When cold(Pump, Injector,Lines ETC) I need less duty with higher Frequency to hit my Target Idle Pressure of 45PSI. So my X Axis is Fuel Temp Y axis is MAP. FYI I monitor Pressure with both a Needle gauge and 3 wire Transducer. I can tell you for sure. Your Pressure is indeed higher when the system is cold. That said think your Gauge is accurate. Best to isolate gauge/Reg from engine HarmonicsThanks for all you do I have been watching your videos for years.
To clarify, it's not so much a problem that the gauge is liquid filled, the issue is more a matter of the gauge being SEALED and able to build pressure against the fluid within its housing which affects the bourdon tube. It's entirely possible to get liquid filled gauges that are able to be vented periodically (feasible if you vent it before taking the reading, if it's in the engine bay you won't be reading it in motion anyway.) Another option could be to modify the gauge by adding a breather tube on top to allow it to constantly be at atmospheric pressure regardless of the temperature (and help mitigate fluid loss from splashing out) As a similar concept, consider an axle breather, same concept, temperatures rise and the pressure safely vents up and out. Simplest option though? Yeah just replace the dang gauge with a non sealed unit. (This isn't directed at anyone in particular, just tossing it out there.)
On liquid-filled gauges there's a port where they are filled this port can be used as a vent to vent the pressure changes that occur. Wouldn't want to do that in a mobile for sure! Got to match the gauge to the application for sure, and that's a good idea to question your measurement device when you think you may have a problem that might not be there. Always double check your meter or gauge. Thank you great video.
Altitude affects pressure gages as well. anything that affects the pressure inside the gage will. example reduction of 1 lb of air pressure from increase in altitude(vented gage) will make the gage read 1 lb higher(approximately). its an imperfect world. we need to understand these things and not get upset by them.
Thank you so much for this video and the link to aeromotive page regarding this. Everything in my entire fuel system was new, and this is exactly what was happening to me, chasing the fluctuating fuel press, actually blew a head gasket due to it being too lean after an adjustment when hot, was reading nearly 50psi, supposed to be Ford 39.whatever psi lol. For as common as aeromotive claim this is, I've asked quite a few, otherwise very knowledgeable individuals, tuners even, with really no help. But this is exactly what it was and exactly how I'd describe it to the people I did ask. Thanks again Eric, you have made a few of my all time favorite RUclips videos. The one with you a Paul rebuilding a t5, I've watched numerous times, helped me disassemble and re assemble a few t5s myself.
Omg! My neighbor was talking to me last week about that issue with his 1964 mustang restoration built. Whe were blinding trusting those glycerin filled gauge.
To be clear, the issue isn't that the gauges are liquid filled, but that they're liquid filled _and_ sealed. Vented, liquid-filled gauges exist- Aeromotive manufactures them- and they solve both the case pressure problem and the shock/vibration problem. But, as ever, excellent tip for people with modified fuel systems to look out for. Thanks for the resources, Eric!
I cut the tip off of mine and it reads accurately and runs better than ever. I will be buying a new gauge because I don’t want the oil in the gauge to make a mess now
This not just an issue with mechanical liquid filled gauges. Almost all pressure gauges, including electronic one, suffer from the similar heat related inaccuracy. Because the change occurs relatively slowly, a computer can sometimes compensate, especially if it knows the temperature of the fluid it is measuring. There are other techniques that can be used for electronics but they are all expensive.
Wow. I feel better. I didn't know what was going on. I was about to buy an adjustable regulator thinking mine was busted. I got other problems with my S2K but I can breath a little easier now.
I wish I would of saw this a month ago because I was having issues with fuel pressure, regulator wasn’t reading properly & it would drops pressure after a while. I now have the car at the shop & im probably gonna get charged an arm & a leg to look at it when it’s probably this exact issue. SMH. Thanks man!
A simple solution to that problem is to just use a T split and a section of braid reinforced fuel line to a normal gauge that's located in an insulated enclosure somewhere near the nose of the car. Vibrations won't affect it anymore and heat won't sway it either. Trucks have this, WW2 planes had this. There's no magic behind it.
I'm nosey, So i would take it apart and wash it out with alcohol, then refill with light oil. Just to see if it made any difference lol. I learn by taking things apart, always have.
The only time i had a non filled fuel pressure guage read steady(within 1psi) is when i had an aftermarket mechanical fuel pump and using no regulator whatsoever, it was a Carter M6900 style fuel pump for my mild build SBC back in the mid 90s, advertised at 6psi, my fuel pressure gauge needle only varied between 5.5 and 6.5 psi, no more, no less. Compared to these $25 mechanical fuel pumps as a stock replacement, advertised at 5psi(Delphi MF0001), but connect a fuel pressure gauge inline, and the needle bounces all over the place showing a much higher reading. I bought that delphi unit for my ZZ4 crate engine, i took it for a test drive, and it ran fine, i've always had the impression and also seeing it on YT that if the fuel pressure was too high, it would overcome the needle and seat, over fill the bowls and you would actually see fuel dribble out of the ventury boosters, but my holley 650(0-080783C) carburator hasnt done it, and the set floats and fuel level stays steady in the fuel bowl via the sight glass.
FYI: Really strange the article. All the glycerin gauges I came across tell you to pinch with a needle a hole in the rubber plug for the first usage. Next advice is to use the gauge in a way the rubber seal is always in the highest position so the glycerin will not spill out.
A lot of gauges are questionable now, more than before, liquid filled or not. The problem goes across quality, price, size, etc. It doesn't seem to matter if its American made or not.
Keep up the good work Eric! Can't wait to see the videos with the new Acura :). Hope to start my own channel about custom motorcycle builds pretty soon and you and other RUclipsrs like HumbleMechanic, EngineeringExplained,, ChrisFix, Edd China and many more sure inspired me to do so!
I use this. Its notoriously inaccurate and i only use them to see if fuel pressure is on or off. The fix is actually just to remove the rubber, to equalise the pressure inside the meter. Still, not really accurate. And opting for electronic pressure sender is really a better choice
Thanks for reaching out, I was working on a fuel pressure problem ( low fuel pressure ) for a long time, I drained the liquid in the fuel pressure gauge and I had steady fuel pressure, however There is also air getting into the fuel line between the tank and fuel pump ( I have installed clear fuel line ), also the carburetor air filter is blocked ( making the engine rev up and down a bit at the same time the air starts coming through the fuel line ) ( about 15 minutes of idle ))
I had one of those things fail. The liquid got dark, thought it was just baked or something. Turns out I had a fuel leak into the gauge, and the inside was full of a gas/glycerin mix. I threw the gauge out and put the stock test port back on. It also would give me odd readings, high when cold, low when hot, and I went through the dance with changing parts for a while as well.
Hi Eric. Thanks for the videos. This issue has been known for decades in the industrial gauge market. The non glycerin filled gauges suffer from the same issue but the percentages of the swings are a lot less than the liquid field due to the amount of volume consumed by the liquid versus the body size of the gauge. I have vacuum gauge is that have a little bar that you rotate that allows the inside of the gauge to normalize with atmospheric pressure this is very high quality gauge and it is non-liquid field. This issue has been going on long time, It’s just most car guys are cheap and don’t wanna spend the money on this type of stuff so these companies just throw the stuff out there and people buy it and buy it and buy it. Great videos. It boils down to you get what you pay for.
Huh, that's interesting, used similar old gauges on alot of cars in the past. Though I never really paid attention to them. Actually, I would have said little sisters. I had a nasty little 65 mustang, had just finished working on. Went inside for lunch. Then went for a test drive around the neighborhood and what had been running great, wouldn't go over like 2k rpm and it would choke and sputter then die. Stopped and popped the hood, my fuel line was having a seizure. My pressure regulator was set all the way down. Turned it back, thinking all was ok. Nope, ran good now but wouldn't go over like 2k. Then noticed my rev limiter was also set to the bottom. After that it was all good. She had went and changed them while I was inside.
I've been chasing what I *think* is a fuel pressure issue in my Fuel injected Jeep Grand Cherokee. Whenever I take a corner at a moderate speed, and step on the gas to accelerate out of the corner, the engine bogs down like either it's flooded, or not getting enough gas...don't know what is causing this. Maybe I should put in a fuel pressure gauge and see what it's doing.
Eric Iv been chasing my tail on my car for a little while now, long story short my fuel pressure was fine and reading good, after a small incident the car started reading max fp, changes 3 differs fp gauges and replaced the same regulator with a new one, checked fuel filters,kinks and cannot seem to figure out why I can't get back down to reg fp (5-7psi) by the way this is on a sbf 302 fox
I remember being told that fuel pumps rarely fail from Eric... In a video sponsored by airtek... So far I am 0 for 5 on airtek fuel pumps. First one the car had no power, wouldn't accelerate. Stock fuel pump died at about 200k, would only push 20psi. Bought an airtek fuel pump, it only pushed 12, brand new, out of the box. The car wouldn't even start. One actually did start the car and read 40psi. Made it almost 25 miles. One didn't even spin. Again, brand new out of the box. I would say crappy fuel pumps are a bigger deal then an inaccurate guage.
You guys are absolutely right. There's nothing stopping you from using a stand-alone gauge. But letting the ECM / PCM monitor fuel pressure would be nice.
So fuel pressure hasn’t changed, it’s just the gauge giving you false information, right? Could you adjust the pressure on your fuel pressure regulator on a cold or warm engine, disregarding the gauges info after it gets hot?
Just watched. Just ordered thier carb 0-15 psi gauge. Will see if it makes a difference. My current AutoMeter liquid filled gauge with equalizer will start to lose pressure after warm up at idle. Then will really drop when driving around from 4 to about 2 psi or less. Would have pull the equalizer pin to reset it to read at 4 psi. I’m thinking I would not have to do it every time. Losing sleep over this! Will see how this one does once received and tested.
so tough question. My car runs for 2 minutes and dies and wont start again and just turns over. I replaced the fuel pump, fuel pressure regulator and fuel filter and the sparkplugs are dry and the system is getting spark. Why does my fuel pressure drop to not enough? fuel pump ground?
my fuel pump on a 1993 cadillac brougham 5.7 failed is it a bad idea to replace it with a high flow pump? the entire car is original. WOuld it cause a problem? should i just go with an oem style pump?
You ain't lying. Crappy gauge and being able to trouble shoot... result headache. Aeromotive make good stuff, I run their regulator, pressure gauge, and filter on my truck. Once you use their stuff.... warning... you don't really want to use anything else.
I just put in a electric fuel pump and filter with all new lines and that regulator gauge and I’m having issues. At highway speeds if I let off the accelerator I’m losing all the fuel pressure and it eventually dies on me. Then if I wait 5-10 minutes it starts right back up. I can drive around town low rpm no problem. What could be the issue. We’ve already swapped another new pump and filter in and checked the regulator. Still having same issue. Wiring seems fine and it’s all new as well. Even got a new battery and alternator. Vented the fuel tank. Gas tank is clean.
Dude i have a 95 ram. Put a new tps, plugs, wires, battery, thermostat. After like 20 miles on the highway throttle becomes unresponsive . I have to let it sit 45 mins then it is ok.
So the gauges we've used our whole lives ain't right? Maybe so. I just installed a new fuel pump,and the injectors and regulator check out good. I've still got intermittent fuel pressure too.
I get F1007 and F1014 codes still searching what they mean. Somebody suggesting it may be crankshaft or timing issue, maybe crankshaft sensor, but I doubt car could be out of timing as it was not opened. Someone suggesting it’s a fuel problem perhaps too much fuel. It’s a Peugeot 207, any idea where to start? Have replaced fuel pump already, seemingly not cause.
im having this same issue but with my oil pressure... same thing? I added a mechanical glycerin filled psi gauge next to my sender and its acting the same as this here.
1994 Ford Explorer 4.0 V6, starts good, runs good, but consisent low fuel pressure of 26lbs. 3 different guages all read same. Replaced fuel filter and regulator. No change. KOEO reading steady 28, KOER reading steady 26. Web search says engine quits at 25. Whats the issue?
I unscrew the diesel fuel cap and normally I hear a hissing sound but not recently. Also recently, my car struggles to start Diesel engine. Are these two observations linked eg fuel leak or fuel hosepipe blocked with debris ? Thanks Eric.
I have a 2008 Chevy Equinox 3.6L, The fuel pressure is at 60 psi but needle is very erratic & the car is misfiring consistently, any idea what this can be?
wait what? they complain about liquid filled gauges and replace them with a liquid filled gauge??! maybe some more indepth explanation to what makes the aeromotive one the better option?
Well that counts out my problem because I don't have a gauge on my crown vic...its running rough and cutting off..I check the pressure at the rail and it just shoots up a little...I compared it to my grand marquis that I just put a new pump on and it sprays out with plenty of pressure...so I thought I needed a new pump in the crown but after installing the new one it hasn't changed anything...I can hear the pump humming and shutting off like normal but hardly any pressure...beautiful Florida day here but feeling a bit discouraged....I know there is a solution
I had the same problems with holley carb.it was leaking fuel and pressure dropped.u ll know when u have excessive black smoke off the exhust.also electric pumps have built in filter may get dirty.or collapsed fuel lines if rubber.😇
It's been 3 months now I'm chasing this issue with my car..the fuel pressure don't drop but on the hwy the car hesitates and when I step on the gas I see the fuel gauge drop 2 to 3 psi instead of going up..I also noticed the pressure would drop significantly when I turn the key on and let the car sit for about an hour so far I heard it's the fuel regulator so I'll go ahead and change that first since it's the cheapest thing..
my problem is my car, 65 gto with 3/2s, when idling smells of fuel out the exhaust. The 2 outside carbs are not supposed to produce fuel when idleing. I have removed the center carb and replaced several parts, im sure its not the center carb. It could be the Holley red f.p. installed. Im thinking of turning down the pressure fromthe pump to my regulator but not sure how to do it. Reg is new too. I adjusted my reg all the way to 0 and it didnt make any difference. Been looking for a description on how to adjust psi from the pump to my reg. cant seem to find any. Any ideas where theres info on adjusting a Holley red?
Question, I have a 2004 4runner v6 and I have a little issue that needs to be fixed. It's got 166k. When I start the car in the morning I get a rough idle for a few seconds. Then it runs normal, I have no idea what to check for that symptom. It doesn't always do it but most of the time in the morning it does. so for I've done new spark plugs, new battery and alternator, new air filter, I can't seem to diagnose and fix the problem. ERIC any tips as to what I can check next?
I’m fighting a PO300 code replaced injectors,plugs wires,coils it’s a Ls swap in 89 c1500 I’m using a 255lph pump,corvette regulator,6an lines and new sending unit. I have 58 psi when it primes and at idle it has 70. Would that be causing my PO300
Why don't you have a "remote mount gauge" and have it in the cockpit...the Glycerin stays same temp as the inside of your car...(I actually made my own from a Direct mount, used a Trerice gauge off EBay that had the diaphragm for low pressure suitable for chemicals equivalent of gasoline) and filled the lines with very light viscosity motor oil...and viola I have a Fuel pressure gauge safe to be cabin mounted...(I wanted to use 1980s Ford Motorsport N.O.S autometer gauges that matched my build)
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#1 cause of fuel pressure problems at SMA.... cars out of gas....
Mmm, got no gas in it.
2 Eric's is one comment!!!
@@ericthecarguy got'ny french fried potaters?
Chunk ERICCEPTION!!!!!!, *insert Inception horn here*
But the needle was on "E" yesterday and it ran
Eric, you need to cut off the tip (pointy part) off of the fill plug. The plug seals the gauge so that the glycerine doesn't leak during shipping. Unfortunately, if you don't create an opening by cutting off the nipple, the outside of the bourdon tube, the part that changes shape as pressure inside it changes, has no reference to atmospheric pressure which is what you're measuring fuel pressure against. If there is a pressure build up inside the gauge case for whatever reason, the needle will indicate a lower reading than if the gauge mechanism was exposed to atmospheric reference pressure. I.E, 9 psi fuel pressure will indicate as 6 psi on the dial if there is a 3 psi pressure build up inside the case. I've seen this problem many, many times in industrial applications, especially in lower pressure ranges like is the case in your application.
Aha!!!!! interesting! explains why the cheapo liq-filled gauge I used on my 91 Storm never acted up on me. I swapped out the glycerine for mineral oil because the provided expansion space was way larger than it should've been & I couldn't find glycerine with which to bring the level up to spec. I decided to push things & leave a smaller bubble for aesthetics, *installing a rubber expansion tube I dyi'd onto the gauge* . I left it open ended & *LOOSELY* packed with a bit of cotton ball to keep out contaminants. Maybe the mineral oil helped as well?
Good point.
Hi Eric,
if you want a "true" reading on a glycerin filled gauges, you will have to cut off the rubber tip on the fill plug on top of the gauge, this is only sealed for transportation. more expensiv guages in industry have a valve on top with clear markings for transport and opperation posittions. i have workt for many years on boats and have sen this a lot. when you heat the guage, the air and glycerine expands, and the pressure inside the gauge increases, dus causing the pressure to read lower than it actually is.
Definitely helpful Eric! I was actually diagnosing inconsistent pressure this past week on a built '17 Subaru STI. Sadly, the gauge wasn't the cause of the problem. (we mount our fprs and gauges on the strut brace usually instead of the engine. Helps a lot with vibration issues)
Turned out it was an issue on the Venturi pump siphon/scavenge setup in the fuel tank. Installed a new Venturi pump and simplifies the system, and the pressure got much more consistent. Less pressure in the return line to the tank!
Needless to say, there was a lot of "tail shaking" going on for us too
Man. I have been fighting with my fuel pressure for months since my build. Thanks for this. Even my Holley has a rubber plug I just released the pressure and finally it all makes sense.
Exactly what my glycerin filled gauge is doing when hot. Drops to 2 psi and adjusting the regulator does nothing. I'm putting in a non liquid filled gauge tomorrow. Thank you so much.
Jim Hand, a prominent old school Pontiac V8 builder found out the liquid filled fuel gauges aren’t accurate when mounted inside the engine compartment, due to temperature fluctuations. Jim literally just pulled the rubber plug and drained the glycerin out, problem fixed! Some times simple is better! 👍👍👍
Eric,
I found the glycerin leaked out. Replaced it with an Edelbrock (Russell) non-liquid gauge. I noticed the fuel pressure increased after I shut off the engine. Needle and seat should have less than 5 psi. Shut off pressure was 6 psi. 70 Firebird stock fuel pump. I dropped the shut off pressure to 5 psi to prevent flooding.
I've only ever had two problems with fuel pressure. One was caused by a bad fuel pump. The other was due to the absence of fuel. :)
Why come no start? No gas. That's why come.
Would you say you had to get a full tank in lol
Dammit. Just got that same guage a month back. Haven't used it yet. Nor will I. I mean it is only 20 bucks, you get what you pay for! Thanks Eric! Useful information as always!
I note the proliferation of electronic pressure gauges, these can monitor oil or fuel pressure and are in the $20 range. They do require a wire from the sensor, one for battery voltage and a ground at the sensor as the sensor might be isolated from ground as it is on my old Honda.
Eric your gauge sounds accurate. I run Fuel Pressure control. 45-100psi to be exact. It's PWM based. When cold(Pump, Injector,Lines ETC) I need less duty with higher Frequency to hit my Target Idle Pressure of 45PSI. So my X Axis is Fuel Temp Y axis is MAP. FYI I monitor Pressure with both a Needle gauge and 3 wire Transducer. I can tell you for sure. Your Pressure is indeed higher when the system is cold. That said think your Gauge is accurate. Best to isolate gauge/Reg from engine HarmonicsThanks for all you do I have been watching your videos for years.
To clarify, it's not so much a problem that the gauge is liquid filled, the issue is more a matter of the gauge being SEALED and able to build pressure against the fluid within its housing which affects the bourdon tube.
It's entirely possible to get liquid filled gauges that are able to be vented periodically (feasible if you vent it before taking the reading, if it's in the engine bay you won't be reading it in motion anyway.)
Another option could be to modify the gauge by adding a breather tube on top to allow it to constantly be at atmospheric pressure regardless of the temperature (and help mitigate fluid loss from splashing out)
As a similar concept, consider an axle breather, same concept, temperatures rise and the pressure safely vents up and out.
Simplest option though? Yeah just replace the dang gauge with a non sealed unit.
(This isn't directed at anyone in particular, just tossing it out there.)
On liquid-filled gauges there's a port where they are filled this port can be used as a vent to vent the pressure changes that occur. Wouldn't want to do that in a mobile for sure! Got to match the gauge to the application for sure, and that's a good idea to question your measurement device when you think you may have a problem that might not be there. Always double check your meter or gauge. Thank you great video.
Altitude affects pressure gages as well. anything that affects the pressure inside the gage will. example reduction of 1 lb of air pressure from increase in altitude(vented gage) will make the gage read 1 lb higher(approximately). its an imperfect world. we need to understand these things and not get upset by them.
Thank you so much for this video and the link to aeromotive page regarding this. Everything in my entire fuel system was new, and this is exactly what was happening to me, chasing the fluctuating fuel press, actually blew a head gasket due to it being too lean after an adjustment when hot, was reading nearly 50psi, supposed to be Ford 39.whatever psi lol. For as common as aeromotive claim this is, I've asked quite a few, otherwise very knowledgeable individuals, tuners even, with really no help. But this is exactly what it was and exactly how I'd describe it to the people I did ask. Thanks again Eric, you have made a few of my all time favorite RUclips videos. The one with you a Paul rebuilding a t5, I've watched numerous times, helped me disassemble and re assemble a few t5s myself.
Omg! My neighbor was talking to me last week about that issue with his 1964 mustang restoration built. Whe were blinding trusting those glycerin filled gauge.
To be clear, the issue isn't that the gauges are liquid filled, but that they're liquid filled _and_ sealed. Vented, liquid-filled gauges exist- Aeromotive manufactures them- and they solve both the case pressure problem and the shock/vibration problem. But, as ever, excellent tip for people with modified fuel systems to look out for. Thanks for the resources, Eric!
I have the Aeromotive gauge and it does the exact same thing. The Aeromotive gauge fixes nothing.
I cut the tip off of mine and it reads accurately and runs better than ever. I will be buying a new gauge because I don’t want the oil in the gauge to make a mess now
This not just an issue with mechanical liquid filled gauges. Almost all pressure gauges, including electronic one, suffer from the similar heat related inaccuracy. Because the change occurs relatively slowly, a computer can sometimes compensate, especially if it knows the temperature of the fluid it is measuring. There are other techniques that can be used for electronics but they are all expensive.
What about a stock fuel pressure sender?
Wow. I feel better. I didn't know what was going on. I was about to buy an adjustable regulator thinking mine was busted. I got other problems with my S2K but I can breath a little easier now.
I wish I would of saw this a month ago because I was having issues with fuel pressure, regulator wasn’t reading properly & it would drops pressure after a while. I now have the car at the shop & im probably gonna get charged an arm & a leg to look at it when it’s probably this exact issue. SMH. Thanks man!
A simple solution to that problem is to just use a T split and a section of braid reinforced fuel line to a normal gauge that's located in an insulated enclosure somewhere near the nose of the car. Vibrations won't affect it anymore and heat won't sway it either. Trucks have this, WW2 planes had this. There's no magic behind it.
Just so as long as some genius doesn't take it to the next level and decide to mount that gauge on their dash.
I'm nosey, So i would take it apart and wash it out with alcohol, then refill with light oil.
Just to see if it made any difference lol.
I learn by taking things apart, always have.
Yeah, bit its outta warranty once you do. So if you mess up the reassembly, you won't get it replaced
The only time i had a non filled fuel pressure guage read steady(within 1psi) is when i had an aftermarket mechanical fuel pump and using no regulator whatsoever, it was a Carter M6900 style fuel pump for my mild build SBC back in the mid 90s, advertised at 6psi, my fuel pressure gauge needle only varied between 5.5 and 6.5 psi, no more, no less. Compared to these $25 mechanical fuel pumps as a stock replacement, advertised at 5psi(Delphi MF0001), but connect a fuel pressure gauge inline, and the needle bounces all over the place showing a much higher reading. I bought that delphi unit for my ZZ4 crate engine, i took it for a test drive, and it ran fine, i've always had the impression and also seeing it on YT that if the fuel pressure was too high, it would overcome the needle and seat, over fill the bowls and you would actually see fuel dribble out of the ventury boosters, but my holley 650(0-080783C) carburator hasnt done it, and the set floats and fuel level stays steady in the fuel bowl via the sight glass.
Hope that You'll post a testing of this. Thanks for the tips.
You are a HERO!!! I've been chasing this problem for the past month
Neat. I never thought about the liquid filled gauges interacting with changes in temp.
FYI: Really strange the article. All the glycerin gauges I came across tell you to pinch with a needle a hole in the rubber plug for the first usage. Next advice is to use the gauge in a way the rubber seal is always in the highest position so the glycerin will not spill out.
Just got my 0-100 PSI Gauge today aaannnd of course it's leaking fluid from the rubber gasket under the pin.
Thx Aeromotive.
A lot of gauges are questionable now, more than before, liquid filled or not. The problem goes across quality, price, size, etc. It doesn't seem to matter if its American made or not.
Thanks for your advise.😎
Thanks for the heads up Eric,I was just gonna order one for my 98 FIREBIRD FORMULA LS1
Keep up the good work Eric! Can't wait to see the videos with the new Acura :). Hope to start my own channel about custom motorcycle builds pretty soon and you and other RUclipsrs like HumbleMechanic, EngineeringExplained,, ChrisFix, Edd China and many more sure inspired me to do so!
I use this. Its notoriously inaccurate and i only use them to see if fuel pressure is on or off.
The fix is actually just to remove the rubber, to equalise the pressure inside the meter.
Still, not really accurate. And opting for electronic pressure sender is really a better choice
I always like your videos before I even start watching because of the content in which you provide. Good luck with the new gauge
I have been chasing an issue in my rx7 thank you
this is NOT a fuel pressure problem, this is a faulty gauge
The Alignment guy says...
The most important part of using measuring equipment is knowing when your measuring equipment is lying to you.
JMF TAG
Thanks for reaching out, I was working on a fuel pressure problem ( low fuel pressure ) for a long time, I drained the liquid in the fuel pressure gauge and I had steady fuel pressure, however There is also air getting into the fuel line between the tank and fuel pump ( I have installed clear fuel line ), also the carburetor air filter is blocked ( making the engine rev up and down a bit at the same time the air starts coming through the fuel line ) ( about 15 minutes of idle ))
Thanks for the continued excellent advice.
I had one of those things fail. The liquid got dark, thought it was just baked or something. Turns out I had a fuel leak into the gauge, and the inside was full of a gas/glycerin mix. I threw the gauge out and put the stock test port back on. It also would give me odd readings, high when cold, low when hot, and I went through the dance with changing parts for a while as well.
Thank you so much for this video! I have been experiencing the exact same problems. Glad to get it resolved!
Hi Eric. Thanks for the videos. This issue has been known for decades in the industrial gauge market. The non glycerin filled gauges suffer from the same issue but the percentages of the swings are a lot less than the liquid field due to the amount of volume consumed by the liquid versus the body size of the gauge. I have vacuum gauge is that have a little bar that you rotate that allows the inside of the gauge to normalize with atmospheric pressure this is very high quality gauge and it is non-liquid field. This issue has been going on long time, It’s just most car guys are cheap and don’t wanna spend the money on this type of stuff so these companies just throw the stuff out there and people buy it and buy it and buy it. Great videos. It boils down to you get what you pay for.
Whered you buy your vacuum gauge ?
@@user-lh1hd5iw7h McMaster Carr
This was so helpful, THANK YOU!!
I love your videos, pure mechanic knowledge
Huh, that's interesting, used similar old gauges on alot of cars in the past. Though I never really paid attention to them. Actually, I would have said little sisters. I had a nasty little 65 mustang, had just finished working on. Went inside for lunch. Then went for a test drive around the neighborhood and what had been running great, wouldn't go over like 2k rpm and it would choke and sputter then die. Stopped and popped the hood, my fuel line was having a seizure. My pressure regulator was set all the way down. Turned it back, thinking all was ok. Nope, ran good now but wouldn't go over like 2k. Then noticed my rev limiter was also set to the bottom. After that it was all good. She had went and changed them while I was inside.
The joys of hot rodding.
I've been chasing what I *think* is a fuel pressure issue in my Fuel injected Jeep Grand Cherokee. Whenever I take a corner at a moderate speed, and step on the gas to accelerate out of the corner, the engine bogs down like either it's flooded, or not getting enough gas...don't know what is causing this. Maybe I should put in a fuel pressure gauge and see what it's doing.
Thanks man. I wish I would’ve came across this before I replaced 2 fuel gauges though.
Eric Iv been chasing my tail on my car for a little while now, long story short my fuel pressure was fine and reading good, after a small incident the car started reading max fp, changes 3 differs fp gauges and replaced the same regulator with a new one, checked fuel filters,kinks and cannot seem to figure out why I can't get back down to reg fp (5-7psi) by the way this is on a sbf 302 fox
Part of the problem is you bought a house brand item. "Jegs" Who makes that?
Myself, Charles and most bikers give their approval on your beard, Eric.
I remember being told that fuel pumps rarely fail from Eric... In a video sponsored by airtek...
So far I am 0 for 5 on airtek fuel pumps. First one the car had no power, wouldn't accelerate. Stock fuel pump died at about 200k, would only push 20psi.
Bought an airtek fuel pump, it only pushed 12, brand new, out of the box. The car wouldn't even start.
One actually did start the car and read 40psi. Made it almost 25 miles. One didn't even spin. Again, brand new out of the box.
I would say crappy fuel pumps are a bigger deal then an inaccurate guage.
great info, i thought the same with the fluid filled gauges
I have modified the fuel hose to little bigger diameter with stock fuel pump result is always low fuel delivery and increased long term fuel trim.
I was expecting something that solves the problem on any vehicle.
If you have an ECM that supports it, you could use a pressure sensor instead of a gauge.
Actually you wouldn't need an ECM. Just a circuit to convert the signal to a readable number.
why do you need an ecm? Gauge can run fine stand alone on a pressure sensor or transducer.
You guys are absolutely right. There's nothing stopping you from using a stand-alone gauge. But letting the ECM / PCM monitor fuel pressure would be nice.
So fuel pressure hasn’t changed, it’s just the gauge giving you false information, right? Could you adjust the pressure on your fuel pressure regulator on a cold or warm engine, disregarding the gauges info after it gets hot?
Just watched. Just ordered thier carb 0-15 psi gauge. Will see if it makes a difference. My current AutoMeter liquid filled gauge with equalizer will start to lose pressure after warm up at idle. Then will really drop when driving around from 4 to about 2 psi or less. Would have pull the equalizer pin to reset it to read at 4 psi. I’m thinking I would not have to do it every time. Losing sleep over this! Will see how this one does once received and tested.
just been chasing a fuel pressure problem on a ford maverick bloody fuel pumps lol
My fuel pressure problems usualy reside once i stop eating ao much taco bell.
superchopper 1996 evap issues hahahaha
My money is in a bad purge valve. XD
Fuel pressure or exhaust backpressure?
Do you get the large evap leak cel code after as well? Lol. 😂
Got a clog in the exhaust? Better get your exhaust valves checked
You’re talking about liquid filled gauges meanwhile the one you’re talking about aeromotives gauge is liquid filled ?
so tough question. My car runs for 2 minutes and dies and wont start again and just turns over. I replaced the fuel pump, fuel pressure regulator and fuel filter and the sparkplugs are dry and the system is getting spark. Why does my fuel pressure drop to not enough? fuel pump ground?
Half the video is a sales pitch 🔥
Selling what?
So,you are telling us that a bad fuel gauge is causing the fuel pump to be at fault?
Yeah! My fuel gauge is bouncing 1/2 in either direction!
Thank heaps mate good, would not have known
Thanks learn something new every day.
my fuel pump on a 1993 cadillac brougham 5.7 failed is it a bad idea to replace it with a high flow pump? the entire car is original. WOuld it cause a problem? should i just go with an oem style pump?
Great article thanks for the information Eric
I thought you were going to say "because people don't change their fuel filters"
I have a clear glass filter. When the motor is not running, should the filter drain or should fuel always be present (full)?
You ain't lying. Crappy gauge and being able to trouble shoot... result headache. Aeromotive make good stuff, I run their regulator, pressure gauge, and filter on my truck. Once you use their stuff.... warning... you don't really want to use anything else.
I just put in a electric fuel pump and filter with all new lines and that regulator gauge and I’m having issues.
At highway speeds if I let off the accelerator I’m losing all the fuel pressure and it eventually dies on me. Then if I wait 5-10 minutes it starts right back up.
I can drive around town low rpm no problem.
What could be the issue. We’ve already swapped another new pump and filter in and checked the regulator. Still having same issue. Wiring seems fine and it’s all new as well. Even got a new battery and alternator. Vented the fuel tank. Gas tank is clean.
Dude i have a 95 ram. Put a new tps, plugs, wires, battery, thermostat. After like 20 miles on the highway throttle becomes unresponsive . I have to let it sit 45 mins then it is ok.
Why are they still allowed to be sold if they're giving false readings. confused
So the gauges we've used our whole lives ain't right? Maybe so. I just installed a new fuel pump,and the injectors and regulator check out good. I've still got intermittent fuel pressure too.
thank you Eric from south Africa
Mad Eric.... Nice. I kinda like it.
Helpful video.
I get F1007 and F1014 codes still searching what they mean. Somebody suggesting it may be crankshaft or timing issue, maybe crankshaft sensor, but I doubt car could be out of timing as it was not opened. Someone suggesting it’s a fuel problem perhaps too much fuel. It’s a Peugeot 207, any idea where to start? Have replaced fuel pump already, seemingly not cause.
I've only installed two liquid filled gauges on my fuel rail...eventually they vibrate so much they actually fall apart .never used one again.
Mine fills the carb and the gauge drops to 0 and runs till the gas is out of carb will the gauge fix that?
Do you think it’s because it’s a cheap guage? I have one on my mustang and it seems to be fine
im having this same issue but with my oil pressure... same thing? I added a mechanical glycerin filled psi gauge next to my sender and its acting the same as this here.
We send back the ones that's not completely liquid-filled on the gauge. That's what the problem is.
1994 Ford Explorer 4.0 V6, starts good, runs good, but consisent low fuel pressure of 26lbs. 3 different guages all read same. Replaced fuel filter and regulator. No change. KOEO reading steady 28, KOER reading steady 26. Web search says engine quits at 25. Whats the issue?
Dude, thank you so much for this video.
I unscrew the diesel fuel cap and normally I hear a hissing sound but not recently. Also recently, my car struggles to start Diesel engine. Are these two observations linked eg fuel leak or fuel hosepipe blocked with debris ? Thanks Eric.
I have a 2008 Chevy Equinox 3.6L, The fuel pressure is at 60 psi but needle is very erratic & the car is misfiring consistently, any idea what this can be?
wait what? they complain about liquid filled gauges and replace them with a liquid filled gauge??! maybe some more indepth explanation to what makes the aeromotive one the better option?
If you follow the link in the description you’ll see the Aeromotive gauge has a pressure relief on the top.
@@ericthecarguy smart
What about putting the gauge in a cool spot. I have one and i sure would hate to waste money.
Well that counts out my problem because I don't have a gauge on my crown vic...its running rough and cutting off..I check the pressure at the rail and it just shoots up a little...I compared it to my grand marquis that I just put a new pump on and it sprays out with plenty of pressure...so I thought I needed a new pump in the crown but after installing the new one it hasn't changed anything...I can hear the pump humming and shutting off like normal but hardly any pressure...beautiful Florida day here but feeling a bit discouraged....I know there is a solution
I had the same problems with holley carb.it was leaking fuel and pressure dropped.u ll know when u have excessive black smoke off the exhust.also electric pumps have built in filter may get dirty.or collapsed fuel lines if rubber.😇
It's been 3 months now I'm chasing this issue with my car..the fuel pressure don't drop but on the hwy the car hesitates and when I step on the gas I see the fuel gauge drop 2 to 3 psi instead of going up..I also noticed the pressure would drop significantly when I turn the key on and let the car sit for about an hour so far I heard it's the fuel regulator so I'll go ahead and change that first since it's the cheapest thing..
my problem is my car, 65 gto with 3/2s, when idling smells of fuel out the exhaust. The 2 outside carbs are not supposed to produce fuel when idleing. I have removed the center carb and replaced several parts, im sure its not the center carb. It could be the Holley red f.p. installed. Im thinking of turning down the pressure fromthe pump to my regulator but not sure how to do it. Reg is new too. I adjusted my reg all the way to 0 and it didnt make any difference.
Been looking for a description on how to adjust psi from the pump to my reg. cant seem to find any. Any ideas where theres info on adjusting a Holley red?
Question, I have a 2004 4runner v6 and I have a little issue that needs to be fixed. It's got 166k. When I start the car in the morning I get a rough idle for a few seconds. Then it runs normal, I have no idea what to check for that symptom. It doesn't always do it but most of the time in the morning it does. so for I've done new spark plugs, new battery and alternator, new air filter, I can't seem to diagnose and fix the problem. ERIC any tips as to what I can check next?
I’m fighting a PO300 code replaced injectors,plugs wires,coils it’s a Ls swap in 89 c1500 I’m using a 255lph pump,corvette regulator,6an lines and new sending unit. I have 58 psi when it primes and at idle it has 70. Would that be causing my PO300
Why don't you have a "remote mount gauge" and have it in the cockpit...the Glycerin stays same temp as the inside of your car...(I actually made my own from a Direct mount, used a Trerice gauge off EBay that had the diaphragm for low pressure suitable for chemicals equivalent of gasoline) and filled the lines with very light viscosity motor oil...and viola I have a Fuel pressure gauge safe to be cabin mounted...(I wanted to use 1980s Ford Motorsport N.O.S autometer gauges that matched my build)