Going lean under acceleration
Thread Starter
Joined: Apr 2009
Posts: 59
Likes: 1
From: Erie/Nottingham, Pa
Going lean under acceleration I am looking for a few extra brain cells to diagnose the problem with my camaro running lean again. The car is a 98' LS1 camaro and it will throw codes for a lean mixture (p131/p151) only under hard acceleration. The only modifications to the car are a cat back exhaust and K&N intake.
I have checked for vacuum leaks and found none (reads 20 inches at idle), run heavy duty fuel system cleaners (BG 44k), replaced the fuel filter, replaced the pcv valve, and cleaned the MAF.
Yesterday I reset the computer after a short burst where the code was set and decided to gradually accelerate going up to 6k rpm in first and second. Under more gradual acceleration to the same high rpm no codes are set.
What would be different about the demands of the engine stabbing the throttle versus gradual accel? I am thinking the fuel pump is running out of steam up top. Pressure regulator issue?
I have checked for vacuum leaks and found none (reads 20 inches at idle), run heavy duty fuel system cleaners (BG 44k), replaced the fuel filter, replaced the pcv valve, and cleaned the MAF.
Yesterday I reset the computer after a short burst where the code was set and decided to gradually accelerate going up to 6k rpm in first and second. Under more gradual acceleration to the same high rpm no codes are set.
What would be different about the demands of the engine stabbing the throttle versus gradual accel? I am thinking the fuel pump is running out of steam up top. Pressure regulator issue?
Thread Starter
Joined: Apr 2009
Posts: 59
Likes: 1
From: Erie/Nottingham, Pa
I finally had a chance to check the fuel pressure while running down the road this evening and I wanted to update this post.
Running at idle, up to temperature 59psi.
Normal driving, smooth acceleration 59psi.
Wide open throttle 55psi.
Shut off after running 50psi.
Would these figures point to a weak fuel pump for an LS1 camaro?
Running at idle, up to temperature 59psi.
Normal driving, smooth acceleration 59psi.
Wide open throttle 55psi.
Shut off after running 50psi.
Would these figures point to a weak fuel pump for an LS1 camaro?
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Thread Starter
Joined: Apr 2009
Posts: 59
Likes: 1
From: Erie/Nottingham, Pa
Thanks for the advice, I installed a good used MAF last night and everything seems to be running correctly now!
If anyone else is having a similar problem you may also be experiencing a stumble around 2500rpm, I thought they were unrelated issues.
https://ls1tech.com/forums/new-ls1-o...-question.html
If anyone else is having a similar problem you may also be experiencing a stumble around 2500rpm, I thought they were unrelated issues.
https://ls1tech.com/forums/new-ls1-o...-question.html
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Teching In
Joined: Jun 2010
Posts: 15
Likes: 0
From: VA
i have just installed a vortech supercharger on my 98 z28 along with a 85mm aluminum intake manifold, 85mm throttle body and Mass air flow. it didnt come with anything to replace the fuel pressure regulator. i got the car back and it ran fine for a day or so and all of the sudden my fuel pump started whining and if i would put a little pressure on the gass it would bog down. does anyone else know anything about this or know of a fuel pressure regulator i should get??
Try the.. i have just installed a vortech supercharger on my 98 z28 along with a 85mm aluminum intake manifold, 85mm throttle body and Mass air flow. it didnt come with anything to replace the fuel pressure regulator. i got the car back and it ran fine for a day or so and all of the sudden my fuel pump started whining and if i would put a little pressure on the gass it would bog down. does anyone else know anything about this or know of a fuel pressure regulator i should get??
