I've seen plenty of new aftermarket sensors that send the wrong values to the ECM, so getting the right one is key. when I changed the throttle body on my 5.3 Chev I made sure I got the OEM Hitachi unit. that's an electric throttle so I don't mess with any cheap crap.
My numbers are all above -10% and fluctuating a lot. I'm gonna try catalytic converters next. I've been 10 months now trying to get my issues found. I'm down to these 2 codes. I changed this part after I watched you video months ago. I was hoping it was going to fix my issues, but it didn't. Thanks for making and sharing these videos.
This was a great video. This info , mixed with common sense troubleshooting and with some other random stuff on message boards led me down the right path to troubleshoot.
When you said vacuum leaks can cause a rich condition I scratched my head, having never thought of that. With the help of Google, I found a few special cases, like a stuck open Evap purge solenoid, a damaged fuel pressure regulator sucking in fuel and air, and a stuck open EGR in a speed density (MAP) engine. The MAP boost from egr air triggers more fuel from the pcm. I guess those are worth bearing in mind if the more common causes like stuck open fuel injector or bad O2 sensor or dirty MAF aren't the case.
I've actually had a few vacuum leaking intake gaskets cause rich codes . Completely opposite what you would think ! Although I've not had one yet on a direct injection one yet . The ones I had were all 99-06 5.3 litres . The first few drove me nuts trying to figure out because it went against what I would normally think could cause a rich code
So, Im thinking that if you command the purge valve off while car is running and watch the pressure in the fuel tank to see if it changes. That might be a way to see if the purge valve is leaking.
It's amazing how Google eavesdrops on every word said during the day today I was working with the scanner 1st time ever I probably said the word fuel trim 20 times and your video pops up a few hours later..
I would be interested to see what the calculated ethanol percentage was on this vehicle. I know on the non flex fuels GM trucks they use the long term trim values to calculate ethanol content.
My Dad always taught us to always have a heavy asbestos blanket laying around in case of spot fires, you throw it over the area quickly and smother fire I’ve been known to clean those sensors with a shot of freon
Kenny, 1 thing I have noticed, you are ending your videos way too fast. If someone is streaming on a device like a roku, in order to give you a like, they have to go back to the video, restart it then like it. After you sign off let the video go for another 15 seconds so, show a pic of the car you were working on or the shop or whatever. You are missing a lot of likes, because they aren't going to bother. Keep up the good work, I'm a retired long time fleet mechanic, you are doing a good job with your videos. D.
I have this P0172 code...-30 ltft as well it was set at idle and at idle I get the -30...People are telling me its the fuel pump...I had a buddy plug the evap purge canister in hope to isolate a over saturated charcoal canister..It still gave way high ltft at idle. Oddly for me driving at like 40 to 50 mph the short and long term fuel trims seem ok...Ive cleaned the MAF sensor even had it unplugged checking the fuel trims and they were wonky...The 02 sensor is about 2 years old..coincidentally I had recently change the purge solenoid???? #13:55 actually I put 2 purge solenoids in just in case 1st was a defect...I work in parts industry I see how many parts are defective..lol.. There was no change...Note..My car is old its a 2003 Buick century but never had this code until I installed the new purge solenoid as I had cleaned old one and then Code came back again that it was clogged and week later the P0172 appeared...
IM HAVING A RITH RUNNING 08 CHEVROLET TAHAO AND I HAVE THE K&N AIR INTAKE SETUP ON MY TRUCK BUT ITS ALL SEPARATED FROM THE HOT AIR UNDER THE HOOD , BUT I HAVE A RICH RUNNING CODE AND A PO 300 CODE TO SO IM GOING TO BE CHECKING YOU OUT ON YOUR FIXS
I've seen plenty of new aftermarket sensors that send the wrong values to the ECM, so getting the right one is key. when I changed the throttle body on my 5.3 Chev I made sure I got the OEM Hitachi unit. that's an electric throttle so I don't mess with any cheap crap.
380,000 miles on 1500 Express van 2003 , 4.3vortec .
Original motor fuel trims under 10 and original CATs .
Amazing GM van .
Keep up the good work my son does the same as you , gets to the root problem instead of throw parts into it, thank for the great video, Rick
My numbers are all above -10% and fluctuating a lot. I'm gonna try catalytic converters next. I've been 10 months now trying to get my issues found. I'm down to these 2 codes. I changed this part after I watched you video months ago. I was hoping it was going to fix my issues, but it didn't. Thanks for making and sharing these videos.
This was a great video. This info , mixed with common sense troubleshooting and with some other random stuff on message boards led me down the right path to troubleshoot.
When you said vacuum leaks can cause a rich condition I scratched my head, having never thought of that. With the help of Google, I found a few special cases, like a stuck open Evap purge solenoid, a damaged fuel pressure regulator sucking in fuel and air, and a stuck open EGR in a speed density (MAP) engine. The MAP boost from egr air triggers more fuel from the pcm. I guess those are worth bearing in mind if the more common causes like stuck open fuel injector or bad O2 sensor or dirty MAF aren't the case.
I've actually had a few vacuum leaking intake gaskets cause rich codes . Completely opposite what you would think ! Although I've not had one yet on a direct injection one yet . The ones I had were all 99-06 5.3 litres . The first few drove me nuts trying to figure out because it went against what I would normally think could cause a rich code
So, Im thinking that if you command the purge valve off while car is running and watch the pressure in the fuel tank to see if it changes. That might be a way to see if the purge valve is leaking.
It's amazing how Google eavesdrops on every word said during the day today I was working with the scanner 1st time ever I probably said the word fuel trim 20 times and your video pops up a few hours later..
Scary , isn't it !!
Sometimes pull off plug and reset the sw that will work but not if sw was bad
Good one I had leaking air on my v10 did the same.
I would be interested to see what the calculated ethanol percentage was on this vehicle. I know on the non flex fuels GM trucks they use the long term trim values to calculate ethanol content.
My Dad always taught us to always have a heavy asbestos blanket laying around in case of spot fires, you throw it over the area quickly and smother fire
I’ve been known to clean those sensors with a shot of freon
Have seen people do that as well since the Freon evaporated so quickly.
Kenny, 1 thing I have noticed, you are ending your videos way too fast. If someone is streaming on a device like a roku, in order to give you a like, they have to go back to the video, restart it then like it. After you sign off let the video go for another 15 seconds so, show a pic of the car you were working on or the shop or whatever. You are missing a lot of likes, because they aren't going to bother.
Keep up the good work, I'm a retired long time fleet mechanic, you are doing a good job with your videos. D.
I have this P0172 code...-30 ltft as well it was set at idle and at idle I get the -30...People are telling me its the fuel pump...I had a buddy plug the evap purge canister in hope to isolate a over saturated charcoal canister..It still gave way high ltft at idle. Oddly for me driving at like 40 to 50 mph the short and long term fuel trims seem ok...Ive cleaned the MAF sensor even had it unplugged checking the fuel trims and they were wonky...The 02 sensor is about 2 years old..coincidentally I had recently change the purge solenoid???? #13:55 actually I put 2 purge solenoids in just in case 1st was a defect...I work in parts industry I see how many parts are defective..lol.. There was no change...Note..My car is old its a 2003 Buick century but never had this code until I installed the new purge solenoid as I had cleaned old one and then Code came back again that it was clogged and week later the P0172 appeared...
Grasias
Why not use a smoke machine for all vacuum leaks? It’s safer than carb cleaner and the engine doesn’t have to be running?
Look fot TSBs
You will find your answerd
Bad cat? Tps?
You look and sound like Rex Huermann.
IM HAVING A RITH RUNNING 08 CHEVROLET TAHAO AND I HAVE THE K&N AIR INTAKE SETUP ON MY TRUCK BUT ITS ALL SEPARATED FROM THE HOT AIR UNDER THE HOOD , BUT I HAVE A RICH RUNNING CODE AND A PO 300 CODE TO SO IM GOING TO BE CHECKING YOU OUT ON YOUR FIXS
Grasias