so the other day, I'm driving.. normally.. not getting on it... and I lost all boost in 2nd and 4th.... 3rd no issues... 5th.. no issue... didnt get an cel's .. just lost boost... went home... turned it off... started it again after about an hour... and all gears were fine and got full boost.....

anyone have an idea why this might happen?

 

Search for GMS1 and you'll see.

 

Ecu brain fart

 

gms1 is most likely ur problem there man.... bring it back to the dealer and make sure they solder all the connections. My uncle had the same issue with his hhr ss and we took apart the tape around the harness and found out the the connections were crimped on and they told him they soldered all the wires lol freaking dealers ........

 

well.. Im gonna say its not the GMS1... when I had it installed, I made sure the dealer soddered the connections ... that's one of the things I had seen alot of talk of on here... there's been no real issue with that since ive had the tune... the HP tune on top of that, has been no real issue either... but obviously, I cant ignore the loss of boost.... I checked the GMS1 wires and connectors.. and saw no issues with that... its possible, but I cant proove it... that not long after a prolonged rain event that the MAF got contaminated perhaps with too much moisture.. this has happened to me before ..but that was during actual driving through the rain... the car was parked in this case ... and the loss of boost wasnt long after I started driving it....

ECU brain fart?? ... hmmm possible?? ... but I will take a double look at the connectors... subsequentially, a couple of days after .. no boost issues... so, im gonna chalk it up to ... "ghost in the Shell"??

 

Pull the codes. May not set MIL, but you may have a code.

 

I know sometimes my cruise control wont work until it shut the car off and start it again...hopefully it dont do it again...I rather have something known to be broken so it can get fix then a random event with no clues

 

ok I was wrong.... I had the same issue again today... no boost in all gears... I got no lights, no CEL, no knock issues... nothing..evrything rain fine... just no boost... so I took it home and I opened the hood, checked the wiring... it all looks tight to me... I decided to disconnect the main terminal to the battery to see if maybe whatever the trouble is, could be killed by refreshing the brain.. and having it relearn everything... I cant say that will fix it... but I gotta start somewhere... next thing will be to take it to advance auto to see if there are any codes.. but I cant imagine there being any if I have no CEL...

please keep coming with the ideas... cause im stumped.. and have no way of pulling the current HP tune... since I have no tuner anymore :0(

 

the Cruise Control is controlled by both the ECM & BCM - it's possible the TB could be dirty - I had a customer come in with CC INOP, checked SI for any new diag or cause failures, did a little fact checking with DVOM and found the TB blade on the IM side was dirty with gunk.. removed it & cleaned it and the CC was working fine..

Also once in awhile the brake switch on the brake pedal goes bad too - which will prevent the cruise control to turn on, also the third brake light also effects the cruise control - if you removed the bulb and replaced it with LED's - this will or may cause the CC not to operate..FYI..

it's possible you have a boost leak some where and need to check every part on your car.. the ECM went into Limp mode.. for it to happen again - i'm thinking it's a boost leak.. i had a small slit on the lower charge coupler and i got CEL - checked everything 2x, until I removed and check every part with fine tooth comb.. found the slit and replaced all the couplers to 5ply SAMCO SPORT and now no more boost leaks..

Most times the dash CEL will or won't come on because the problem isn't going to effect the drive-ability or the operation of the engine.. When the ECM/BCM notices a problem, you'll set a MIL code when this happens, the ECM will store it until it's looked at or it's cleared and not turn-on the dash CEL..

 

Stop resetting it, and read the damn code.

 

You'd be surprised, I had P0236 more often than not until a dealer figured out what to do with the harness on the TMAP and it never once set a CEL, but there was at least 1 or more codes when I lost all boost. If you've lost boost one of the sensors is going to report a fault since values read from the MAF, TMAP and MAP are all compared for loss. These values are used to set the dynamic codes generally involved with boost loss.