Hi, 2009 cobalt ss turbo, injen cai, magnaflow exhaust . no tune. had car fluttering boost, sounded like bov stuck open, brought to dealer, got new turbo put on, still same issue, poped p2178 and p0103 at first a few times, then now they stopped coming up few days ago and now i got p0101. wondering whats my options.

 

check for vacuum leaks or faulty MAF on the P2178

 

GM said they tried a new maf and still had same issue and put my maf back in. then put new turbo on it. nice to get a new turbo out of it but still not fixxing the problem. i checked for boost leaks and checked all hoses, dont seem to be issue. with out an osciloscope is it possible to check my maf for proper function?

 

im also hearing a noise that is almost sounding like a valve seating, put obv isnt that. sounds turbo related, possible bov is churping?

 

multimeter to check voltages? im not sure what it would supposed to be reading on the cobalts.

do you have an A/F gauge? im wondering if your running lean/rich

did the deealer check the tune?

check your intercooler for cracks read thats an issue on the ss/tc

check your Oxygen sensors

 

Untuned injen intake is bad news bears. Try taking it off?

 

yeah you definitely need to be tuned for that intake...

 

i must have read right over that. lol

 

i have no tune on the car that im aware of, i contacted previous owner and am in the process of checking if there was at some point and may have been lost. dont have a/f gauge and can not see fuel trims, which makes this hard to diagnose. dont really want to bring to dealer to pay retail out for something i can just end up spending money a tune or a scan tool to read my datalogs. with an untuned ingen u think it will cause troubles?

 

yeah i think itll make you run lean without tune

 

ok, well if i can borrow a friends genesis scan tool and i can monitor my a/f what should i be looking for? I also wonder why i never had no problems with this for 3-4months and now its starting to do it every day

 

that is strange...but i would get tuned for the intake and that should help a lot. search on here, things like intake and downpipe especially will cause the car to not run right

 

yeah but why would i get the code contently now when i never changed anything and it just started to come up? possible colder air outside this time of year?

 

that's true man, idk. that is weird. i say check for boost leaks first, then get tune if there are none.

 

maybe a the MAFs wiring got pinched and everytime it gets a small bump it irritates it? just a guess

 

checked maf wiring back to were it connects into the thicker harness. no chafe,pinch. i heard storys of a bank 1, 1 o2 sensor cauing havic, anychance?

 

so still havnt re-poped engine light but still have no boost, unless u put it to the floor and wait

 

bump?

 

See my sig for boost leak test. You absolutely must be able to perform a boost leak test if you're going to own a turbo-car. Likely, you have a leak, and need to find it. What were you doing right before this started happening? Did you let off after a full-throttle/full-boost romp and hear a pop? Did you bottom out the front of the car at all? Need details.

 

im going to do a boost test in the next few days. and no pop nodda

 

Let us know how the boost leak test comes out. I'll be super-surprised if you don't have one.

 

i had injen intake on my car untuned for 4000 miles no problem, so i doubt thats an issue.i actually had charge pipe (hot and cold side) intake and intercooler with no tune for that about 4000 miles with absolutely no problem what so ever. i had the same problem with my car and it was the lower charge pipe sensor, once it is takin out it is hard to get back in with out stripping it out, so id make sure that it is pushed all the way in and seated properly and also check to make sure it didnt come unplugged somehow . thats what my problem was and i was thowing the same codes.

 

Made a boost leak tester today. No leak found. Holds pressure. Ill have to start back probing sensors and check them next I guess. Any other suggestions before I try the tune.

 

Count me super-surprised, then. I'd run the boost leak test again with the bumper cover off so you can be sure you're not leaking around the intercooler area, but if you're absolutely sure you don't have leak, try another TMAP sensor. You might just be better off taking it in if it's repeatable all the time. Dealers love to throw ECM's and MAF sensors at these codes.

 

I went to dealer. Over war retry for maf sensor. They tried a new maf first and road tested it after clearing CMDTCs. And popped codes again. So they put my sensor back in. I work for ford and can't pick up any data logs with my IDS scantool. I was thinking my checking the sensor voltages with the dealer pinpoint tests and hope for luck. But I heard injen causes problems a lot of the time. Ran boost leak tester. Quiet environment and can't hear any hissing with it holding 23psi in the piping an cooler without it dropping.