3.8 ecotec wont rev when you stab the throttle

[Immortality]

I would suggest you wire something up or alternately get yourself an ALDL cable so you can see what is happening in the PCM.

Tazzi from Envious Customs is the man for a cable.

 

[Sabbath']

Has this issue just started or has it been like this for a while, and if it's just started, did you do anything to the motor (you said it's in a rock crawler, is this since you've swapped the motor in?)

I'd be hunting for a possible vac leak given the idle issue as well as the other symptoms.

The ecotec has a hose which connects to the bottom of the TB that likes to pop off if disturbed slightly, the other end goes into a block behind the motor on the drivers side, should be able to trace it back pretty easily and check both ends.

 

[Immortality]

^^^ that line is for the purge valve. I would think this would have been deleted for a off road vehicle?

 

[Sabbath']

^^^ that line is for the purge valve. I would think this would have been deleted for a off road vehicle?

Possibly, OP doesnt state how long the motor's been in and causing trouble though.

 

[Rat rod jim]

Motors been just installed. So trying to iron it all out, just got a adjustable fuel reg aswell

 

[Immortality]

Then you way as well delete the purge valve and block off the vacuum fitting at the bottom of the TB if you haven't already done so. It's part of the anti-pollution stuff and I don't think you will have a fuel tank breather/evaporator, charcoal canister line going back to the engine anyway.

With these engines been MAF you need to keep the factory enclosed PCV system otherwise you are introducing a vacuum leak/un-metered air into the engine. If you want to set up an external breather/catch can setup for the engine you will need to block the PCV fitting inside intake manifold. The PCV valve is fitted between the plenum and LIM.

 

[Rat rod jim]

I got it going lot better, revs up now. Put a adjustable fuel reg on but it works at around 45psi

 

[Immortality]

That is correct, factory injectors are rated at 3bar/43psi. The FPR needs to be manifold vacuum referenced too otherwise it will over-fuel at idle/high vacuum conditions.

 

[Rat rod jim]

Thanks heaps for all input