2006 Infiniti G35 Rough Idle - P0300 Random Misfire - Bad Fuel injectors
HTML-код
- Опубликовано: 14 окт 2024
- 2006 Infiniti G35 came in with a rough idle. Car had 200,000km so we replaced spark plugs. Still had slight rough idle. Not quite a dead misfire and sometimes worse than others. Seemed to drive pretty well.
These cars don't have misfire counters so not the nicest to track down. Found bank1 fuel trims to be pretty normal. Bank2 were +15% to +25% total trims. Didn't seem to change much with revving the engine. Didn't suspect vacuum leak and nothing found on smoke test. Clear flood crank sounded pretty even.
Checked secondary ignition waveforms with an inductive probe and all looked good. No dropouts seen even though engine was misfiring.
Next easiest step was to check fuel injector current ramp patterns through the fuse. This lead us to the problem. One was very bad, one was partially lower than the "good" ones and one was slightly lower.
Removed the intake manifold and confirmed two bad injectors and one partially bad injector via testing resistance.
After repair the car felt like it had an extra 100 horse power!
I think you just solved all my problems bro and now Ik I just needa check the voltage of the fuel injector to test them
@Xi Clipz Awesome! Hope it all works out for ya!
@@eurbanautotech hi my Infiniti G35 is having car trouble. The code is a P0300, it says multiple misfires, it’s not the spark plug or coil. What else is the issue with the car? It doesn’t accelerate all the way, it only goes 4 miles per hour when gassing it and accelerating. It can go in all gears but dies out sometimes.
@Jolene Martin Hi there. Sorry I missed your comment earlier. Did you get your car fixed?
I understand the video is a year old now, but is still valuable information. Diagnosing a 2008 Infiniti FX35, has a P0300. (BTW, misfire data on these Nissans/Infinitis is located under the special functions section of your diag. tool. Shows real time and past misfire data.) Misfires are on cylinders 1 and 3, very pronounced fishbite misses. Coils (OEM Hitachi) and plugs (NGK Iridium) are all new and firing, although those 2 cylinders still have what appear as new unused plugs, while the other 4 show obvious signs of combustion events taking place. Ohm readings on the suspect cylinders injectors was 12.2 cold. Using a multimeter on #1 injector and back probing the injector connector, with the key in run, connecting from the Red/Black power and battery neg I'm reading full battery voltage, from the Red ground to battery positive it reads 9.6 volts. Switching to a 300ma incandescent test light, Red/Black probed and grounded to Bat- lights up, but not Red probed and (grounded) to Bat+. With the vehicle running, shows the same low voltage and no injector pulse at all (test light noid light)lol. I can hear both injectors clicking with a stethoscope, not loudly, but audible. Seems like the ground side switch from the PCM is weak or failing. This is also a new to the car PCM from a salvage yard, old PCM apparently was cooking coils on a daily basis. Without a PICO or amp clamp, do you have any suggestions for a next step? Thanks for the content brother!
@DustmanDiagnostics2 Thanks for the comment! Now I can't wait until a Nissan rolls through the shop to look at the misfire info! I completely missed that. Sure would have made many cars nicer to work on in the past...
Seems like you got it pretty well figured. For checking the control wires (switched ground from PCM) it sure is nice to see the voltages on a labscope. Makes ya feel more comfortable making the call. The only thing I'd to do make sure is try checking RIGHT at the PCM. Backprobe one of the injector control wires directly from the PCM and run that to your test light. If your test light flickers when directly connected to the PCM then you know you have a bad wire and not a bad PCM.
Also it's a good idea to check your test light on a good injector. Make sure you can see it flicker. It should be able to but for whatever reason it may not be sensitive enough to such a quick current draw. If it flickers on a good injector then you KNOW that it not flickering on the bad injector is a valid test. But if you can't see it flicker on a good injector then it's not a valid test.
Otherwise what you can do is remove the whole fuel rail then tie it up in the air. Put little sandwich baggies around the injectors to see which are spraying and roughly how much their spraying. Then crank it for a few seconds to compare. This way you can also swap injectors to verify that the injectors are indeed good or not. Rather messy and slightly time consuming but it'll get the job done.
All in all I think you're on the right track. "New doesn't always mean good". Especially new/used. But ya, definitely try and make sure it's not a wiring problem.
Good luck and thanks for watching and sharing your info! Let me know what you find.
@@eurbanautotech Out of curiosity, that and I'm tired of looking, would you happen to have the pin out for the ECM? Specifically injectors 1 and 3? I'll get back on it as soon as I get done with the other dozen or so emergency calls today and let you know what turns up. Thanks for the feedback, been a very long time since I've heard anything remotely educational as a suggestion. The diapers I have to change from the "shops" around here are some very dirty ones, and they have the equipment to diagnose complex issues, but lack the education or willingness to apply themselves in any capacity. It's too bad really, folks are desperate to find gifted diagnosticians who will correctly diagnose and repair issues without getting murdered with the bill, or worse yet, paying an invoice for an unrepaired problematic vehicle. How they can charge for not repairing the customer's concern, and throwing parts at the problem hoping one will stick is beyond my moral compass.
Keep up the great content, pretty sure you have a nice sized client list that will only let you do their repairs based solely by listening to your diagnostic approach and humor of course. Thanks brother!
@@eurbanautotech I meant to follow up earlier but my schedule has been a bit hectic. The 2008 Infiniti FX diagnosis ended up being a compromised driver in the PCM for injectors 1 and 3 only. Removed the fuel rail and cranked the engine, showed spray pattern on #'s 2,4,5, and 6. Moved injectors 1 and 3 to the 2 and 4 location, cranked again, still no injector pulse on 1 and 3. Continuity between the red wire on the injector connectors and pins 123 (#1) and 122(#2) on the PCM was positive. Loaded circuit testing showed 10.9 volts on the injector positive lead to battery negative, and battery voltage from injector negative to battery positive. All injectors read 11.9 ohms at testing (37 degrees F). Injector pulse duration during misfires was 2.3ms on bank 2, 3.3-4.1ms on bank 1. Replaced PCM with used e-Bay unit MEC85-390 B1, programmed NATS, VIn#, and throttle air volume relearn and she roared to life on all 6. Next day the P0420 code popped up from the owner driving with the misfire even though I said "You ought not to", lol. $1371.10 for a bank 1 catalytic converter. Anyway, thanks for the response, the content, and conversation. Perhaps this information will come in handy for someone else. BTW, the cause of all the issues stemmed from an audio system modification that was pulling in the realm of 200+ amps of current through the stock battery to body ground wire and alternator to battery feed (8 gauge at best). Upsized them both to 1/0 OFC. Your welcome!
I have a 2007 g35 where do I hook up my fuel pressure tester please help
@@louisvillalba7695 If I remember correctly, there isn't a pressure test port on the fuel rail. In that case you would have to fabricate an inline tee'd fitting much like you'd have to do with Toyota's.
So I have a 2006 Infiniti G 35 coupe are you saying that that has clear flood mode? I’d like to do that to eliminate my one second timing chain rattle at cold start up.
Can a bad fuel pump cause this I’ve changed out injectors coils and spark fuel rail and cam sensors haven’t touched the crank sensor and ordered new fuel pump it’s a nightmare help me anyway you can please
hey there... what tool is the one you are using at 15:00 to check the fuel injectors ?????
@Just a guy with some tools That wasn't used for checking the fuel injectors. It was used to try and see if the misfire was lack of spark. It's an inductive wand that can pick up the magnetic field of an ignition coil when it fires and convert that to a voltage that can be displayed on a labscope. There are quite a few different designs from different companies. I like this one (by Pico) the most because it's flexible. It does require an oscilloscope though.
www.aeswave.com/COP-probe-p9335.html
You can get ones that don't require an oscilloscope. They have internal circuitry that attempts to pick up a signal from the magnetic field and analyzes it. If it's close enough to a valid signal then it'll blink an LED to show you that it's detected a valid spark event.
www.amazon.ca/Hickok-76562-COP-Quick-Probe/dp/B0021UPE58
Personally, I don't like the idea of one of those. Having used one with a labscope you get a feel for how hard it can be to pick up a valid signal even on ones you KNOW are firing. Some coils are more insulated than others. So I don't like the idea of making some kind of diagnostic call based on some tool that's blinking an LED when I don't know what went into the decision to blink the LED...
For checking fuel injectors I used an amp clamp to capture a waveform on my labscope of the current going through the injectors. If all the injectors were good then they'd all use roughly the same amount of current. But I could clearly see some were using way less current than others. So that's how I knew the problem was from faulty injectors.
dammmmmmmmm. I'm now convinced my p0300 is caused by bad FI. thanxs! I'll do that ohms test as well this weekemd
@Karlos Mejia Nice. I hope it works out for ya!
Hi, I have a 2005 g35 coupe with the rev up motor. I’m about to change out the right VVT Solenoid tomorrow but I’m afraid that’s not gonna be the fix. I’m getting a P0300 and it kinda idles a little rough but never gets too low in the Rpms. It does stutter a little when you try to rev it up or accelerate and get to up to speeds. I think it could be clogged cats, but any help would be greatly appreciated. I haven’t had the chance to get it lifted and get underneath it.
@peyton baker Hi. I was going to type a big response to your question but then I thought it might be easier to post a quick video. I'm not sure if this format works or not but I thought I'd try it out!
ruclips.net/video/ykB8A0teLEg/видео.html
Hey, did you ever end up finding the problem im have the same issues with my z
check ur oil
Please where can I place my fuel pressure tester at im so
Confused please help
great video thank you
@ELIJAH MCINTOSH Thanks! Glad you enjoyed it!
I have this same problem with a code popping up 03 350z had one for cylinder 1 also but fixed that with new coil packs and plugs now its just P0300 itll idle at 700-800rpm then die down to 500-600rpm and shoot back up car feeels fine driving only happens at idle. Only thing i can think of at this point is bad injectors or an exhaust leak i have and the o2s arent correcting it right. may be wrong but any thoughts please... my obd doesnt read misfires i dont believe
@username Hey, sorry I totally missed your comment. Did you get your car figured out?
@@eurbanautotech thanks for replying. Still havent fixed it.. got this car a year ago and ive just been replacing the previous owners mistakes since but this video and a few others had me check out my obd reader and only thing i can find thats noticable is my 02b2s1 voltage jumps a lot .08-.5 while the other three stay between .1- .3 volts and fuel system 1 is ol fault. Assuming that one 02 is the problem and starting to go out any info back will help so i dont have to spend extra money not needed
@@eurbanautotech also the car runs great its only at idle and with the air on in the car it wont misfire then
@username Is it misfiring at all? Or just the drop in RPM at idle? The first thing that pops into my head when people talk about this kind of complaint is the A/C compressor. What happens when you turn the HVAC blower fan all the way off? Does it still drop? Some older vehicles drop quite a bit when the compressor kicks in. Uncomfortably so. Then it'll jump right back to the regular idle RPM. We have a lot of customers with early 2000s cars of all different kinds of makes and models this do that and have been doing it for years with no other driveability problems.
I would recommend cleaning the throttle body. If it's particularly dirty I would recommend getting a replacement gasket for it and removing the unit. This throttle body is in a better spot than some but still kinda hard to see and get to. Much easier to clean if it's in your hand. Also makes it easier to try and keep all the gunk and spray away from the motor electronics. When you're done you'd like to be able to see an air gap between the throttle blade and the bore. Once it's clean and dry you can reinstall it (bolts don't need to be crazy tight).
Then you'll want to try and do an idle air relearn. That gap between the blade and the bore is important. That's designed for the minimum airflow needed to idle the engine. When it gets plugged up with carbon the ECM learns to open the TB more. When you clean it you free up that passage way again so the normal amount of air can flow. The ECM doesn't know you cleaned it so it continues to hold the blade open more. This results in an elevated idle RPM. Sometimes by a LOT!
Every car has a different relearn procedure. Sometimes it can be difficult finding out what the exact procedure for your specific car is. Some cars have a specific sequence of events. Some you disconnect the battery for 10+ seconds, then go to key on engine off for 10-30 seconds. Some require a scantool. And some learn on their own. Of those, some learn quickly and others can take a LONG TIME!
I didn't see anything in Prodemand or AllData (these procedures can be buried if they're in there at all). But I did come up with this link. Definitely worth a shot.
www.nissanhelp.com/diy/z/projects/nissan_z_idle_air_volume_learning.php
@@eurbanautotech it sounds like a slight misfire every 20-30 seconds at idle when the compressor is off i feel the car shake a slight bit not bad at all my needle drops down itll stay like that for a good 5-10 seconds then itll shoot back up like its normal but its constant even when the car is warmed up when it happens it (sounds like if you blew your cheeks out and made the mouth popping noise faintly at the exhaust) i recently replaced a knock sensor for the car so did all the gaskets from the valve covers and up besides the throttle body cause i kept it on the plenum i did clean it out a good bit though and did the relearn procedure after it all was put back.. new coils new spark plugs thr car sounds and feels great when you get on the gas its only at idle
On my 03 it says what cylinder it’s on w my foxtrout scanner
Mine marked me for service engine soon and I went to go change the ignition coils bc that’s what the scanner marked but it still detects a misfire car smells like gas n runs fine just noticed the loss in power
@Matthew-ib8bm How are the spark plugs?
@@eurbanautotech I just changed the spark plugs and valve cover gasket today but found this hose that broken but can’t seem to find where I can buy it
@@eurbanautotechat 16:15 where your tool is do you know the name of the 2 hoses above it
@Matthew-ib8bm I can't get a good look and Alldata has horrible pictures but I suspect you're talking about the PCV hoses. There's a breather hose that'll connect a valve cover to the main intake duct just before the throttle body. Then there's the PCV vacuum hose that'll connect a valve cover to the intake manifold itself. It's quite common for them to break as the oil vapors break down the rubber. You can Google it to get an idea but unfortunately it can be hard to know if parts you see from Google searches are actually for YOUR vehicle or not. Best to go to a large parts store and get them to look it up or check something like RockAuto
This car has a mass air flow sensor. The engine computer relies VERY heavily on it. So when these hoses break they allow air to get into the engine that the mass air flow sensor doesn't see so the engine computer doesn't know to give it the proper amount of fuel. Depending on the size of the leak this can have all kinds of adverse effects on how the running of the vehicle.
did it fix it ?
@JOEY SHARKEY Yup! Not only smooth but felt like it had an extra 100 horse power with the new injectors. The car actually now felt fast!
Cam position sensor bank 1 or 2. Id replace both. Fixed. I just fixed the p0300. A faulty Cam position sensor will give you all types of codes. Replace them thank me later
honestly that might not be the solution but i would change out the spark plugs, coil packs, cam sensors, and a new oil change
Mine has the 0300 code and backfires at idle could it be the same thing
@THEsimpleThingsFR Backfires at idle? I would think probably not. Unfortunately the injectors on this car are a little trickier to get to. You have to pull the intake plenum off. Not the hardest job but definitely takes some work. If the injectors were bad enough to cause something like that then just a simple resistance measurement with a multimeter would show if you had a bad injector or not. Typically injectors have a resistance right around 12.5ohms when cold. I consider 11-14ohms to be pretty normal. The big thing is they all should be very close to each other. Within 0.5ohms. If you have a major problem caused by a bad fuel injector then I'd usually expect to see one of them around 20-40ohms. That's DEFINITELY a bad injector!
I would give your intake hose a check. These can be a real pain to work with. I take them off as one assembly. They seem like you can take them off in pieces but it puts way too much strain on them. Because of this I've seen a bunch of these with tears in the folds on the bottom side. This allows air to get in past the mass air flow sensor so the car doesn't know about it and messes up the air fuel ratio. It can especially be bad at idle because as the engine rocks back and forth it can cause these tears to open and close quickly. So the air fuel ratio can wildly swing back and forth.
Let me know what you find.
@@eurbanautotech so this can or can’t cause backfire at idle bc that’s what’s happening
@THEsimpleThingsFR Normally when I think about backfiring I think about ignition timing being off. That CAN still happen on modern vehicles but is rather rare. With things like this there are just so many things to consider that it can become easy to get stuck chasing your tail and not really get anywhere. That's why I find it can be nice to go after some basics. Instead of just trying to find the problem sometimes it's more beneficial to try and rule some things out. That way you have less stuff to think about.
If you can get to the injectors then a simple resistance measurement is nice. That's not the whole story but if they all test nice then it's enough to forget about them for now.
Pulling the spark plugs can be good. Bad spark plugs won't cause a backfire but they can give you hints as to what's going on. Are they soaked in fuel? Are all of them soaked? Or just one? Maybe an entire bank is soaked in fuel but the other side is good. This can help your narrow things down.
Again, these intake hoses are super common to rip and they're super easy to check. If you flex the hose and reach underneath you should be able to feel the tears. Probably get a finger in there. Or use a mirror. This may not be the whole probably but maybe it's making the main problem become much worse.
Was the car idling lower than usual?
@Kami_dred Yup. Didn't really feel like a major misfire. Which is surprising considering how bad the one injector tested. Just felt like a rough idle and lack of power.
@@eurbanautotech was it shaking at idle?
@macknumber9 Not really. Murmurs more like it. Enough to know there were partial misfires. Not smooth/uniform like a vacuum leak or anything else that's constant. But also not a definite hard misfire. Just an uncomfortable idle that's enough to make you feel like something's wrong without definitely knowing what.
@EUrbanAutoTech oh ok...I'm getting a shake at idle and I can not pinpoint it....ran injector cleaner in and changed plugs wires and coilpack....going to actually remove plenum to get to injectors and test their resistance valued and manually clean them...
@macknumber9 Did you end up getting your car figured?