Car won't stop running super rich
06-02-2014, 12:47 PM
#1
Intermediate
Thread Starter
Car won't stop running super rich
Hoping to get some feedback from members on here that I'm having a problem with.
Car is a 2005
Airaid intake
Kooks headers and mid pipe
Magna flow rear section
Comp 230/234 cam and stock 243's.
When I would go wot with the car it would black smoke like a diesel. I bought the car with the work done to it and it had previously been tuned.
So I went to the local lsx tuner that my friends have had luck with and he tuned the car and pick up a little bit of power but it was still smoking. He said it was the valve guide that were warn down allowing the oil to seep through and that's where the smoke was coming from. So I got a set of patriot stage 3 243 heads and he put them on but didn't tune the car. Car is running rich again and still smokes. I told him about the issue and he put it on the Dyno and at 4Gk rpms the car just dumped fuel and hit around a 10.0 afr. So he tried to lean it out on the second run and it did so until the magical 4k rpm spot it and it hit that 10.0 afr. He thinks it's the injectors and someone said pcm and someone else said fuel pressure regulator. Can anyone give me some insight on this please?
Car is a 2005
Airaid intake
Kooks headers and mid pipe
Magna flow rear section
Comp 230/234 cam and stock 243's.
When I would go wot with the car it would black smoke like a diesel. I bought the car with the work done to it and it had previously been tuned.
So I went to the local lsx tuner that my friends have had luck with and he tuned the car and pick up a little bit of power but it was still smoking. He said it was the valve guide that were warn down allowing the oil to seep through and that's where the smoke was coming from. So I got a set of patriot stage 3 243 heads and he put them on but didn't tune the car. Car is running rich again and still smokes. I told him about the issue and he put it on the Dyno and at 4Gk rpms the car just dumped fuel and hit around a 10.0 afr. So he tried to lean it out on the second run and it did so until the magical 4k rpm spot it and it hit that 10.0 afr. He thinks it's the injectors and someone said pcm and someone else said fuel pressure regulator. Can anyone give me some insight on this please?
06-03-2014, 02:13 AM
#2
Burning Brakes
You should be able to monitor the fuel pressure during the run... that would either confirm or eliminate the fuel pressure regulator as a problem.
If the regulator is good then you could have a faulty injector.
Which side is he taking the AFR reading from? If you swap the sniffer from one side to the other and there is a significant difference between the two sides then that be a way to determine which side the bad injector is on if you have a bad one at all. It would at least narrow it down to 4 possible injectors. Process of elimination would isolate the bad injector.
I'm new to MAF... but could a bad MAF cause this issue? I know on the Chrysler engines I would also look at the MAP sensor as a possible cause... but GM does not use MAP so thats little help to you.
I wish i could be of more help... Please keep us posted.
SPEED SAFE, NICK
If the regulator is good then you could have a faulty injector.
Which side is he taking the AFR reading from? If you swap the sniffer from one side to the other and there is a significant difference between the two sides then that be a way to determine which side the bad injector is on if you have a bad one at all. It would at least narrow it down to 4 possible injectors. Process of elimination would isolate the bad injector.
I'm new to MAF... but could a bad MAF cause this issue? I know on the Chrysler engines I would also look at the MAP sensor as a possible cause... but GM does not use MAP so thats little help to you.
I wish i could be of more help... Please keep us posted.
SPEED SAFE, NICK
06-03-2014, 02:33 AM
#3
Navigator
Member Since: Jun 2014
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Try
Try the fuel pressure regulator diaphram it may b sticking, or sensor, but sounds like injector. On sensors reads a lean condition, not a lean cylinder. In turn ecm compensates and richen fuel to mixture. Severity of compensation depends on # of injectors malfunctioning/clogged etc..
Hoping to get some feedback from members on here that I'm having a problem with.
Car is a 2005
Airaid intake
Kooks headers and mid pipe
Magna flow rear section
Comp 230/234 cam and stock 243's.
When I would go wot with the car it would black smoke like a diesel. I bought the car with the work done to it and it had previously been tuned.
So I went to the local lsx tuner that my friends have had luck with and he tuned the car and pick up a little bit of power but it was still smoking. He said it was the valve guide that were warn down allowing the oil to seep through and that's where the smoke was coming from. So I got a set of patriot stage 3 243 heads and he put them on but didn't tune the car. Car is running rich again and still smokes. I told him about the issue and he put it on the Dyno and at 4Gk rpms the car just dumped fuel and hit around a 10.0 afr. So he tried to lean it out on the second run and it did so until the magical 4k rpm spot it and it hit that 10.0 afr. He thinks it's the injectors and someone said pcm and someone else said fuel pressure regulator. Can anyone give me some insight on this please?
Car is a 2005
Airaid intake
Kooks headers and mid pipe
Magna flow rear section
Comp 230/234 cam and stock 243's.
When I would go wot with the car it would black smoke like a diesel. I bought the car with the work done to it and it had previously been tuned.
So I went to the local lsx tuner that my friends have had luck with and he tuned the car and pick up a little bit of power but it was still smoking. He said it was the valve guide that were warn down allowing the oil to seep through and that's where the smoke was coming from. So I got a set of patriot stage 3 243 heads and he put them on but didn't tune the car. Car is running rich again and still smokes. I told him about the issue and he put it on the Dyno and at 4Gk rpms the car just dumped fuel and hit around a 10.0 afr. So he tried to lean it out on the second run and it did so until the magical 4k rpm spot it and it hit that 10.0 afr. He thinks it's the injectors and someone said pcm and someone else said fuel pressure regulator. Can anyone give me some insight on this please?
06-03-2014, 10:40 AM
#4
Supporting Vendor
The tuner didn't log fuel pressure?
Was part throttle fueling in line?
Sounds like more diagnostic is needed before anyone can guess where the actual problem lies.
Thanks
Was part throttle fueling in line?
Sounds like more diagnostic is needed before anyone can guess where the actual problem lies.
Thanks
07-23-2014, 04:56 AM
#5
Le Mans Master
Member Since: Aug 2005
Location: CA.
Posts: 5,255
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St. Jude Donor '13-'14-'15
1st Did you change your fuel injectors ?
Lt's are notorious for running rich at P/T fuel---Reason is that the new 02 bung locations are moved BACK from stock---This gives your ECM false data as it thinks it is running lean in PT so its always adding fuel ---lean because the 02's aren't heating up properly because of their further aft locations--Most common issue with LT's
A positive fuel trim for a lean condition isn't a big deal at P/T say it's +15% however at WOT the ECM will add that same % to your WOT fuel as a safety If you tuned your engine in PE for a 12.5 WOT AFR adding 15% will make your WOT fuel now a pig rich 10.65 a real mosquito killer !!!
basically whatever the fuel trims are at "JUST BEFORE GOING TO WOT" if positive wll be added to WOT as well--You need to shoot for LTFT trims to be at "0" or slightly negative-----------------If you have a negative fuel trim "JBGWOT the ECM will always lock on "0" so the ECM will never subtract fuel at WOT as a safety
Lt's are notorious for running rich at P/T fuel---Reason is that the new 02 bung locations are moved BACK from stock---This gives your ECM false data as it thinks it is running lean in PT so its always adding fuel ---lean because the 02's aren't heating up properly because of their further aft locations--Most common issue with LT's
A positive fuel trim for a lean condition isn't a big deal at P/T say it's +15% however at WOT the ECM will add that same % to your WOT fuel as a safety If you tuned your engine in PE for a 12.5 WOT AFR adding 15% will make your WOT fuel now a pig rich 10.65 a real mosquito killer !!!
basically whatever the fuel trims are at "JUST BEFORE GOING TO WOT" if positive wll be added to WOT as well--You need to shoot for LTFT trims to be at "0" or slightly negative-----------------If you have a negative fuel trim "JBGWOT the ECM will always lock on "0" so the ECM will never subtract fuel at WOT as a safety