Im still having intermittent driveability issues with my car, and I want to see if anybody has any ideas on what the hell is going on.

The back story is this: For a month or two now the car bucks occasionally while driving in 3rd or 4th gear with VERY LIGHT throttle, ALWAYS around lower-mid RPMS like 1500-3000. It happens very occasionally, but enough to be a worry. After it starts bucking I try to increase the throttle but get no real power and can only boost about 5psi.

It initially had set NO CEL's. However, I did get one CEL just last week randomly even though the car had been running fine. My shop was closed so I couldnt scan the computer, but Onstar told me it was a "Air intake system" code.

So, I went home, removed my Dejon intake and went back to stock. The car runs better on the stock intake when everything is fine. However, I still get the SAME incidents where it bucks and loses power, so apparently the intake wasn't really the issue????

Im confused as the incidents still produce no CEL.

Does anybody have any thoughts? Has anyone experienced this.


BTW, as my sig says, Im only GMS1 with the Dejon SRI that is now removed.

 

I have a similar issue but it happens to me randomy off the line in first gear.
To make it stop jumping i just shift into second and im fine.
I dony know if that is the exact same problem but maybe my input may help.

 

Seems like this is becoming more 'common' with gms1. The code I get is po236. Even if you don't have a CEL, check when it happens and there most likely will be a code. It limits my boost to 5psi and I get some fluttering as well. I've gone back to stock intake, checked the t-bolt clamps several times, checked the map sensors, etc. Everything appears to be ok and it runs fine when the code isn't present.

 

omg mine does the exact same thing. I am trifecta tuned to 25 psi and for some reason my car after i start it will only boost to 5-7 psi and will NOT flash a CEL but if i hit clear engine codes on my intercepter gauge the car will start boosting fine. So let me try to say that more clearly:
1) have NO CEL's
2) press the clear CEL button on interceptor
3) car runs fine
I cannot explain it but it gets really annoying because i have to hit clear CEL's everytime i start my car otherwise it won't run right

 

Have you tried sending a datalog to Vince, when that happens? It's kind of weird it's happening on other tunes though. Do you have the 3 bar map sensors as well?

 

i have sent datalogs to him but i think i need to send another. I actually just got a tune update so i am in the middle of datalogging now . I have done like 5 datalogs already. I guess i will try again

 

Boost leak.

 

Lol,

how many of these GM stage 1 boost/ sensor issues are we going to have.

P0236
P0238

Boost leaks after turbo. Could be the charge piping, intercooler, or look around the sensors as well.

 

Okay, so this morning I left for work.

After a mile the car started the usually bucking and stuttering, but it was much more persistent. Then I finally got a CEL and was limited to 5psi boost.

I stopped at my shop and scanned the computer with the Tech II.

P0101- MAF sensor performance issue
P0106- MAP sensor performance issue

The car has stopped bucking for now, but the CEL is still on and I can only boost 5psi.... no "reduced power" light though...

 

I last drove the car Staurday evening - not real hard as I made a Taco Cabana run ( Brisket tacos FTMFW ! ) and all was well. No more than a 4 mile round trip.

Took it to work today, and even at first something felt "off" - it wasn't until it was warmed up and I gave it a little gas that I noticed - 5 lbs of boost was all she had !

Talk about a slug.

I called Onstar, and the guy gave me the code of P0236. I searched, and just got done looking under the hood. Zero lines off that I can tell, and when I start it it idles fine. I did notice just a moment ago that if I give it a little gas at idle I hear pops as it decels - they are quite noticeable, and it did not do that before that I know of.

The code says turbo issue - the searched threads I have looked over seem to indicate anything from a GMS1 sensor to something to do w/ the vaccum tank.

Anyone have the "real skinny" on this ?

My car is bone stock save the the stage kit - just turned 11K this morning.

I'll hit the dealer Friday AM, but if there is anything I can play w/ 'til then - short of clearing the code - I am all ears.


Thanks !


Britt

 

Sounds to me like:

1) Debris on the MAF from reinstalling the stock inlet ducting. Make sure the bolts are tight and not stripped and that the MAF is very secure.
2) Check the map and ensure it's properly seated/sealed and isn't coming loose. If it is you may need to remove it to ensure it hasn't broken clean off. Friend of mine recently got a similar code on his SC, pulled the MAP, damned thing had snapped the tip right off!

 

I just pulled code P2188 - the car has not been driven since I pulled it into the garage yesterday - it goes to the dealer Friday.

Cracked IC, maybe ?

TTT !!

Britt

 

Could just be a simple boost leak. You can hear the "shhhhhhhhhhhhh" sound when your IC is cracked.

 

My car does the same thing, bucking in first gear, and in 4th& 5th when I accelerate and let off the gas a bit. I also had the p0236 code once with max 5psi boost. Dealer didn't know what was wrong. Still having the issue, I also went back to the stock intake, checked all vacuum lines and tightened all tbolts.... If one of us gets this fixed, there will be alot of happy people.

I also have gms1 btw, k&n drop in and a few mods

 

I have rewired the lower map sensor. The connectors the dealer put on had been heated to the point of melting through the insulation. Since they were all bundled together I could see there being an intermittent short. It hasn't been long enough to tell for sure, but I haven't had any codes since (it's been about a week).

Not a great picture but you can pretty much see it

 

Good grief. That's a "professional" job, too.

 

Wow that's insane

I can't see all of us that's having this issue, having a boost leak

 

Yeah i think we can pretty much say that the dealership knows not what it does.