2G Little pipe that comes off the intake and idle surge problem

[Rollandp]

Hi I’m taking this 1995 GST off a family members hands and it’s currently having some idle surge problems and has a P0325 knock sensor code. I would love any help and advice to fix this problem.

For starters what is the tube that I’m missing in the picture. It looks like it connects the air intake and the charge pipe together. Correct me if I’m wrong. I think that will help to have hopefully .

I’m going to replace the knock sensor and wire. Is the knock send or located under the intake manifold at the back of the engine?

Any other possible fixes to the idle surge issue would be much welcomed!

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[97egl]

There used to be a pipe going from there to the blow off valve. Engine has had modification done to the charge pipes. I'd guess it probably has a FMIC and they just vented the BOV to the atmosphere. This modification shouldn't cause surging at idle.

I would do a boost leak test first thing to try and fix the surging. I'm guessing you'll find a lot of leaks. Might be enough to cause surging. It may also be the modifications done to the car causing the surge if they were done without a tune.

You are correct about the knock sensor location

 

[Rollandp]

Great thank you!

do you think I should check the IAC while I’m at it?

 

[Pjj]

do a boost leak test first and go from there

 

[steve]

This modification shouldn't cause surging at idle.

Unless the BOV isn't sealing at idle. Then it's a huge leak.

 

[Rollandp]

Sweet! What size cuppler fits on the turbo for this car?