Been having a problem, I'm not sure if it was in existence before I put the turbo on or not (I bought the truck and then put the turbo on it)

at idle it will randomly every 2 minutes or so start idling rough. The AFR goes way lean about 15.2-16.0. I also just recognized that the AC compressor also shuts off when it happens (if the AC compressor is on to begin with)

also if I get on it a lot, and then come to a stop it does it really bad

sometimes if I barely get on it and then come to an abrupt stop it will do it and even shut off it is so bad

I've checked for vacuum leaks, all hoses are good- unless the gasket for the intake is bad. I've also replaced the fuel filter. My fuel pressure is at 65 psi at idle, but it does not fluctuate when the rough idle occurs.

Anyone have any advice on what to look into?

 

Have you spoken with your tuner about this???

There are several things that could be wrong. Did you give your tuner the correct injector data???

What is your AFR when running normal and under load???

Can you put the Fuel pressure gauge on and watch the gauge under load as you drive around???

 

Does it go lean then rich?

 

sorry for the slow response


I have not yet talked to him about it. I'll email him

AFR when running normal is between 14.6-15.1

under load it is 10.6

when the tuner tuned it, he tuned it to 11.5, so my AFR gauge might be off (but it shows correct AFR at idle when running right.. +-14.6)

the AFR goes all over the place if you watch it for a while. It will idle rough go lean then go back to normal for a while then go in the 13's, sometimes 12's and back to 14's

I have a fuel pressure gauge so I can see the fuel pressure on it at all times, it idles in the 65 psi range, if I romp on it w/ no boost it shoots up to about 75 then goes back down to 65. In boost it goes to about 68-70psi. Could my regulator be bad? Not sure what side effects that would cause

 

not necessarily, most of the time it goes back to 14.6

 

cat test and rear 02 test still on in the tune?

 

The rear o2s were deleted

 

I emailed the tuner.. waiting to see what they will say

 

I received no reply from the tuner...

also, I noticed that it does it all the time and really bad when it is in OPEN loop. When it is in CLOSED loop it clears up, then randomly comes back.

sometimes right when I start the truck up, while it is still in OPEN loop, it barely idles and dies completely

my guess is the PCM is trying to cover up the problem in CLOSED loop but can't do it good enough. Does this point more towards a mechanical problem than tuning? I'm going to pull the entire intake off this weekend to see how the gaskets look as a vacuum leak really makes sense since it does it really bad in open loop

 

I took the intake off and noticed that the intake gasket was really flat. I replaced it with a new one and the problem still exists...