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So im turning to the community on this one... 2008 turbo ss, zzp stage 1 tune on 93, 3 bar maps, zzp catless downpipe, it has been a bit finicky since spring rolled around, kinda popping in heavy throttle, but i put fresh gas in it and it stopped, also noted some extra loud lifter tick on startup every once and a while but that goes away quikly like it should, the other day i was driving some backroads and went wot in second at about 2500 rpm and she went like hell for a moment and had a light pop so i lifted. Cruised for a sec and noticed the car had no juice, boost goes from negative to zero, and shes about as as gutless as it gets, got to my friends house and checked all the charge pipes making sure theyre attached, and they were on and holding up, mind you it popped no codes and ran slightly rough, took it for a short 10mile drive and about 8 miles in it finally kicked the engine light, so i got to my destination the harbor freight parkinglot checked the codes and it was a p0101 mass airflow code, i cleared the code and the car would turnover, start, and immediately die if i feathered the gas it would rev up but itnwould eventually just stall out..so i ran live data on it and there was no fluctuation in the reading on the MAF... I unplugged the MAF and the car started and ran, i gently drove it home. Ordered a new MAF got it today, i installed it properly, tried starting the car and same symptoms, starts and stalls out, rev it for a few seconds if i can catch it and it idled like crap but atleast idled, now it pops 3 codes p0100 p0101 and a p0114 all are MAF related.. but still no power, no boost. but whenrunning live data i do see fluctuation so i know it had a reading, and ive tried a known working MAF, ive been going thru it and not finding a problem, maf checks out as good, tried another pcm, still ***** itself out unless the MAF is unplugged.. i took the loom off the harness between MAF and pcm and all looks okay, and then lastnight i unplugged the MAP sensor on the manifold and the boost gauge spiked to 30 but the car wouldnt run.. i figure if it was a boost leak it would atleast make some boost, but that isnt the case here, everything looks good on inspection... gonna try cleaning the cam position sensor, maybe its not reading well but the car is ok with it?? Maybe throttle position sensor? Im lost. Everything reads "normal" with live data... anyone have any ideas? I will post data pics when i get service
The P0101 points to a boost leak, visually the air charge system may look ok but still be leaking. I'm not sure what intercooler you have, but if it's the stock one you may have a broken end tank. A broken end tank will certainly prevent you from making any boost. I recommend building/buying a boost leak tester and confirming that there isn't a leak. Given the problems, I'd pull the bumper cover while doing the boost leak test so you can inspect the intercooler also.
also noted some extra loud lifter tick on startup every once and a while but that goes away quikly like it should
This part sounds like your Chain Tensioner is failing. I've never seen a Cobalt truly have loud lifter tick (not saying it isn't possible), but I have experienced a failing Chain Tensioner, and on a cold start, it sounds just like that for a handful of seconds before fading away.
Not something to sleep on either. If your tensioner fails, you're going to have a bad day.
I mean, even not making boost doesnt explain why when i unplug the MAF, the car runs well, plug in the maf and it gets all pissed off and wont run, i am finding some strange wiring stuff going on and following it, the yellow wire on the maf is supposed to be 5v and its 5v untill plugged in where it gets 2.4v im no expert but i believe thats not supposed to be that way lol
And the loud lifter sound could just be cause ive been running royal purple, im going to put mobil 1 in it this oil change and we will see if theres a difference, the tensioner is less than 5k miles old, granted its been about 2 years of sitting with minimal driving etc, but after the rebuild it got 4k miles put on it.. and since i started driving it daily i havent heard that loud diesel lifter noise lol
Last edited by Blackturbo08; May 19, 2022 at 10:53 PM.
Because the car operates on the base air load tables with no maf, plug the maf back in and it runs based on maf air load. So the air the maf is seeing isn't the actual air the car is getting, pointing to either a boost leak or a wiring issue (I'm leaning heavily towards a boost leak).
With the original P0101 code occurring after a pop and the car running horrid with the maf plugged in you likely have a boost leak. It will cost you a few dollars at Home-D to build one and will help a significant amount with a turbo'd car.
After you confirm no boost leak then start in on the wiring.
Because the car operates on the base air load tables with no maf, plug the maf back in and it runs based on maf air load. So the air the maf is seeing isn't the actual air the car is getting, pointing to either a boost leak or a wiring issue (I'm leaning heavily towards a boost leak).
With the original P0101 code occurring after a pop and the car running horrid with the maf plugged in you likely have a boost leak. It will cost you a few dollars at Home-D to build one and will help a significant amount with a turbo'd car.
After you confirm no boost leak then start in on the wiring.
im gonna give a leak test a shot, forgive my stupidity but a substantial enough leak to watch my boost gauge go to 0 from -20 at wot in any gear, should be easily spotted no? I mean the car achieves zero boost whatsoever, i would assume a blown charge pipe or coupler or even the IC would have a relatively large hole in it to never reach any pressure
It doesn't take a massive hole to prevent any boost from building. The end tanks of the intercooler can crack and are difficult to see since it's buried under the bumper cover (an extreme example of a cracked intercooler with a broken end tank), as well as the ECU not allowing boost due to the P0101 code as it's trying to prevent the turbo from an over speed event as well as further engine damage.
Make sure you do a boost leak and not a vacuum leak, you need to pressurize the system to at least your boost spike pressure to verify you have no leaks.
It doesn't take a massive hole to prevent any boost from building. The end tanks of the intercooler can crack and are difficult to see since it's buried under the bumper cover (an extreme example of a cracked intercooler with a broken end tank), as well as the ECU not allowing boost due to the P0101 code as it's trying to prevent the turbo from an over speed event as well as further engine damage.
Make sure you do a boost leak and not a vacuum leak, you need to pressurize the system to at least your boost spike pressure to verify you have no leaks.
Well ill be damned... built a nice little coupler, and sure as **** i couldnt build any pressure whatsoever, i could hear the air rushing on the cold side, so i took the bumper off and found it was blown, see the attached picture, seeing as shes my daily right now i had to rig her up with a smaller ic, but its crazy cause as long as ive owned this car ive only ever seen 22-23 psi, now shes rolling 25psi, i feel pretty dumb for not listening to the many suggestions of boost leak test, i really do appreciate everyones help with this !!!
