I was taking my son to daycare this morning when the light turned yellow so I stepped on it in 2nd to get through and as soon as my boost gauge hit 25psi and building the engine started knocking and a CEL came on.

It blinked for a few seconds and went away, I got it to boost up again and it did the same thing, but only at around 25psi or better. Is this an issue with the sensor hitting like others have had or could it be bad gas??

Stage 1 and 38k miles and never had an issue before.

 

If I remember the SS even with the Turbo upgrade kit should really not be going over 25 PSI. It sounds like a over boost condition.

It could be someing with the wastegate or something else not releasing.

I am sure someone here has had this happen and can explaine it better.

 

It has boosted that high ever since I bought it 2 years ago. I am not sure why it would be doing this all of a sudden. Do you think the MAP sensor wis hitting?

 

COULD be bad gas, or it may be that the diaphram on the BPV has broken (may be the reason it won't hold boost over a certain psi). Stupid question, but you did put 93 in at the last fill right? That can rule out the bad gas. Try if you can to head to a Pep Boys or Advanced Auto around you and get the code scanned, then report here what they found.

 

I only put in 93 octane but I don't know about some of these gas stations these days. I am headed to Richmond for the Nascar race this weekend so maybe I can get it scanned Sunday when I get back. If not I guess I will drop it off at the dealership first thing Monday.

 

Since the engine was under high torque conditions, it may well be the lower TMAP pinching against the A/C compressor. First thing that I'd check. BTW, for comparison, I've never seen over 22psi with the kit, even under perfect atmospheric conditions for my geographic area. Not sure where you live, though (mountains; beach; etc)...

 

I think that the GM engineer said the highest under best conditions was 24 PSI but then again the gauge calibration could be a little off. Every gauge in a car is never 100% in most cars.

 

I now see 25 on my gauge in 2nd and third, 20 in first, without the trifecta tune, just the stage 1 (done properly finally).

I'm virtually at sea level in Santa Monica.

I guess the gauges can be off, but it sure feels like 25, hell it feels like 125.

IMO

 

Just what it was told by the engineer.

Also getting a reading at max boost is not all that easy as often you are more busy watching where you are going.

I have a digital one and have the light set to come on at 20 plus PSI. I have seen 24 for a flash but the norm is 22-23.

 

I've never really paid too much attention to the gauge, but after getting it back from the dealer (and wanting to make sure for myself it was done right) I found a stretch of Olympic that is 3 lanes each way and for about 1/2 mile virtually empty. (In LA this is almost impossible).

So I went up and down it I think 5 times and each time it pulled the same.

20 psi in first, 25 in the next two gears and then dropped a little before I had to shut down and stop, though I'll admit with so much torque steer you do spend a lot of time driving and less time looking at any gauge.

Once again maybe my gauge is off, but the butt dynometer says it's good.

Now the only thing I need to do (knock on wood) is add some better tires than the oems.

IMO