Hi !

I have an 08 LNF and it started to surge just after I worked on mu A/C in the car... I checked batterie and fuses and all seems to be normal.... I didn't play in mechanic yet ! So how it's possible that surge came ?

Please help me !

Max

 

What do u mean by surge?

 

I think he means that his idle goes up and down.

This is caused by Kr in my car. Make sure all of your motor mounts are good, there is no metal on metal contact in the engine bay, and that no tools or bolts got left lose.

Does it only do it with the AC on?
Does the car have an aftermarket tune?

 

I have a tune made on a dyno, an Injen air Intake and a ZZP downpipe. What I mean is that when I drop throttle, I hear surge in any gear... (For me surge is when compressed air return in the turbo).... I think the A/C is not the cause... But I don't know !

 

I mean when I drop throttle, i hear sound that is air returning in the turbo

 

Can you get a video of it for us?

Surge is very rare on these cars. Flutter is common though.

 

Ah. Okay.

Check all of the vacuum lines that comes from the solenoid on you intake manifold. Some run close to, or on, AC lines and may haven been damaged. The solenoid has a power connector and three tubes coming off of it; it is left offset on the IM. Trace the lines and check the connections.

 

 

But, I didn't work in the ''hood'' for the A/C. I only worked by the interior of the car... So how vaccum lines can be damaged ?

 

Sounds like flutter to me. Are there any pending codes? See you don't have a check engine light on.

 

No check engine, boost gauge is ok, it doesn't become crazy....

 

Here, why do you say it's flutter ? what is the difference between surge and flutter ? I now that surge is dangerous for my turbo :S ! So I don't want to break it !

 

yeah man thats turbo flutter. you can ease your mind with that because its better then surging someone correct me if im wrong though but it could be fixed with a tune or theres something not tight

 

I already have a tune...

 

here man read this it may help ya out. could be the BPV spring if you have a forge or even the stock bpv solenoid could be bad

https://www.cobaltss.net/forums/08-1...m-help-317217/

 

do you think if I change my bpv th eproblem will be solve ? now I have the stock bpv

 

you can always try it and see what happens

 

That would be ur bpv not opening most likely. Check vac lines, check if solenoid is plugged in, bypass solenoid and hook bpv straight to manifold , if that fixes it, replace bpv solinoid

 

Some vids of surge and flutter

 

Sounds like the problem i had before. Does it sound close to that when your driving?

 

that's not compressor surge, that sounds like flutter to me.
Listen to what everyone is telling you, check the bypass valve, the electrical connection to that solenoid, and all the vacuum lines.
Take a picture of the bypass valve and post it here, just for us to make sure that the previous owner didn't change to a blow off valve setup. (bypass valve is the plastic cap looking thing on the side of compressor outlet.)

Some people like changing the spring inside the bypass valve to a stronger spring, that is unnecessary and it can cause the valve flutter you have.

If this is a new problem in the car, it is likely what everyone has been recommending, vacuum hose problem, bad solenoid, etc.

 

Is flutterdump a bad thing? Mine does this when i hit boost and let the throttle out half

 

I find that very common on my car. Should be audible if you have an intake.

 

I have an Injen CAI and yes it's very audible. Just wanted to confirm. I wish it did it more lol