Okay, its me again. The guy with the severe overboosting problem. But now i have another problem. But allow me to update you all on my history before i ask your help.

My car has previously been in the shop for over 2 months with a severe overboosting problem. The vehicle was hitting over 20 psi with just GM stage 2. After a GM engineer came and looked at the car, he determined it was the boost actuator had been knocked out of alignment (aparently during the stage 2 install). It was NOT the cat, and whatever the engineer did fixed the problem.

Well i have the car back now and there is another serious issue. During repeated hard runs around 5K and higher, the RPM will just refuse to go higher and start making popping noises and start bouncing. Its almost like it just completely runs out of fuel.

It does this in any gear (mostly 2nd and 3rd) but the boost is completely normal!! (17psi or less).

At first it only did it on cold nights (32 F or colder) so i assumed it was because of my one step colder spark plugs. So i replaced them with stock replacement plugs and the problem apparently disapeared. But now the problem is back!!

The weird thing is that the car runs super strong sometimes but then it will do this and i won't even be able to hit 80mph on a 1/2 mile road!!!!

It did throw a CEL once but after i disconnected/reconnected the battery, it went away!

I also wanted to mention the fact that the supercharger is so hot after this happens, that i can not touch the blower at all.

Please help! My dealership is bending over backwards to help me and i really want to solve this issue without bothering them!

 

dude, just bring it back. tghey should be bending over backwards. they saold you a car that is broken, therefor the need to fix it.

as for the cel going away, when you disconnect the battery for 10 to 20 minutes, it resets the adaptives and the moniters all go down. the cel is no longer on because you told everthing to forget it, so they did. just give it a drive cycle and it will prob be back. as soon as it does, bring the bitch back to the dealership

 

Thanks for your quick response man, i'm desparate for advice nowadays. Well i did the battery disconnect thing like several months ago and the CEL hasn't come back on since despite the problem constantly re-occuring.

I find it amazing that my engine can be having such a catastrophic problem and the computer just doesn't seem to care!! No lights of any kind have come on since that one loley CEL.

I want to take it back but the problem occurs at random and knowing my luck the mechanic won't be able to repeat the problem.

 

bump. I really need help here!

 

if you're still having a problem... take it back man... that sounds like a serious issue. Boosting as high as you did for such a long period can damage your engine components. Anyone here running over ~18PSI is running additional cooling mods to handle the extra heat the SC is producing. I'd seriously be considering lemoning the car and getting GM to buy it back. GM dosen't even reccomend going over 18PSI.

 

Thanks for your input. But i just don't forsee there being any internal damage. Especially since this only happens during certain temperatures. Most of the time, the car runs amazing and gets great gas mileage.

I have a couple of ideas so please anybody lemme know what you think.

1) The Injen intake + cold weather + my cars freakish boost levels= causing the car to run lean at upper RPM.

2) The blower is overheating from the freakish boost levels and causing severe knock. To the point that the engine will no longer accelerate past a certain RPM.

3) Battery/electrical problem resulting in misfires at upper RPM. This would explain why it mostly only happens at night (because of headlights)

Any other ideas? I'm considering reverting back to stock airbox with the injen filter (will it fit?) and seeing if that resolves the problem.

Again thanks in advance for ANY suggestions.

 

This is a shot in the dark here...but maybe reflashing the computer would help you out. If the comp was flashed when your stage 2 was done...then it learned the fuel curves for the high boost levels...then when you got it back down to the safe boost levels...maybe the computer is getting some incorrect readings from the mass air and screwing up the fuel ratio. I dunno...just something to consider. <shrug>

 

Thats an excellent suggestion and probably right, but get this.

I swapped back to the stock air intake and stock filter yesterday, and then ran the car through 1st, 2nd, and 3rd about 10 times. And the problem is completely gone.

Something about that Injen intake was causing my car to go hay-wire at high RPMs.

Its the weirdest thing i have ever seen. An intake and filter causing near-catastrophic power loss.

 

hey what can you do... cars have a very "touchy" MAF...

 

I know right!

Fortunately during my previous problem, my dealership ordered me an entire stock intake assembly with a new MAF sensor and everything. So when i reinstalled the stock airbox, i was also installing a brand new MAF.

Why am i the only person that had this problem

Well at least its fixed. But now there is barely any audible supercharger whine

 

This has happened to my car two times. One time before i put the stage 2 on and then just today.

 

Mine only seem to happen after i ran the car hard once. Usually only in cooler weather. How about yours? I am 99.9% sure it is something to do with the MAF.

 

The next time you get a CEL, don't disconnect your battery to make it go away! It's trying to tell you something, and instead of listening, you cutting out it's tongue. A CEL is a GOOD thing when trying to determine a problem. It's telling you where the problem is so you can fix it. Get it scanned and find out what the code means. Then clear the CEL the right way, instead of this silly ass battery disconnecting stuff.

 

Well actually, i recently had the CEL come on again during the problem, but one day later it went off. Man, why does everyone start giving me ideas AFTER i remove half my mods to solve the problem. :S

But like i said, with the stock airbox and filter, and a new MAF, the problem is COMPLETELY gone. Can a MAF sensor cause a car to run extremely lean?

 

Mine does is when i get on it real hard the dealer said that it was something to do with the manifold. That is the coad that they said it threw. so i dont know does your car start running at half power and somethng comes up in the desplay.

 

Are you talking about the exhaust manifold? What can be wrong with a header? Its just a metal tube!

But by a freakish coincidence, my GM honed exhaust manifold just came in. I'll examine the stock manifold and post up if anything is out of the norm.

 

No the intake manifold i think that when the boost gets too high it is not getting enough gas.

What is g/85.

 

Looking at my sig eh?

G85 means different things for different years.

05, 06, and some 07 = Limited Slip Diff and Recaro Seats
07= Limited Slip

 

i see have you taken you car to the dealer for that problem or what when the problem happens i just turn that car off for a couple of min then it runs fine. So i dont know what the problem is.

 

Well like i said. I can get one good run out of the car, but then if i try to run the car again hard, it starts freaking out.

This leads me to beleive its a heat issue.

Either way, replacing the MAF sensor and putting the stock airbox back on fixed it.

 

I haven't heard of a CAI causing that to happen. Maybe it was just the MAF. If the CEL went away the code should still be stored for a limited time after. Take it to the dealership and have them scan it to see what it was.

 

I am going to take my car to school to run it on the scan tool. To see the code that it thru.

 

Will a store bought OBD scanner tool be able to pick up CEL's that have already disapeared?

 

Im not sure about that where did you get it from the one that im am going to use is just from my high school. The codes stay in the ecu for a wile

 

Sounds to me like you had a bad MAF, but the more you talk about it. Sounds like you were going off the MAF tables with air coming in. What people don't know is that you need to have about 3-4 inches of straight pipe between the filter and MAF. I haven't seen a INJEN intake but I would think a company of that statue would know that. Sounds like you need to find a friend that has an HP tuners and play with ur MAF tables some. With the smaller pulley and etc, that can happen.