Big problems out of nowhere....

[87gninpa]

Car was running better than it has in weeks, then at work today, i changed the oil and trans fluid and thats where the trouble started. After refilling fluids, i disconnected the ecm, cranked the engine for about 10 secs then reconnected and when it fired up the car ran like absolute crap!!!! when i gave it throttle, it stumbled initially but sounded fine after the stumble. it almost sounds like there is a horrible exhaust leak but there was none before......then while driving the car home, it sounded like a motorcycle out the tailpipes, would take any boost, and the car would hesitate when the converter locked up. my vaccum numbers used to be 18 at idle in park and 14 at idle in drive. now they are 16 at idle in park, and 11 at idle in drive(with a nasty hesitation. when i got home, i hooked up the scanmaster and everything was normal as usual, except the blms were at 145,w hich im assuming means lean???? i am really lost here, i checked all vaccuum hoses and sensors and i cant find anything. would this seem to be a trans problem or an engine problem? any help at all would be appreciated. once again, everything was completely normal before the oil and trans fluid changes........any other info needed, please ask..

 

[87gninpa]

forgot to mention, the vaccum guage does not even twitch or stutter, its just less than it was, could thi swhole thing be a vaccuum leak? if so, from where would it make that big of a deal? i dont remember removing any lines, and i checked all of the major ones. and also, the oil is clear, not milky so ive pretty much outruled a head gasket

 

[denn454]

i've bot a very unscientific idea. unplug the ecm and crank it again, plug it back in and see if it does anything for you.

There is no reason for that to help, but if the car runs god there is no reason for it to start running bad because of a oil change and disconnectiong the ecm.

If i had t guess i'd say something else happend and its just a coincidence that it happend now.

Look for an exhaust leak, start at the headers and work your way back and tighten every bolt you can find. That wouldnt' explain anything, but its an easy thing to fix.

 

[87gninpa]

I tried unplugging ang replugging the ecm numerous times and also reseating the chip, and no difference. i checked for exhaust leaks and found nothing, especially since ive put on new headers and full exhaust this month. im really out of ideas here, can anyone help????? its my driver and im currently carless......... any ideas at all would be greatly appreciated

 

[John Larkin]

Check uppipe and intercooler hoses. One might have slipped. Shouldn't affect vacuum though. Maybe when you cranked it, it flooded. Probably should pull spark plugs and see if they look ok. I'm grabbing at straws now.

 

[87gninpa]

yea, i think when i get home from work ill pull the plugs and recheck all vaccum lines again. The more i think about it, it seems like a nasty vaccum leak. thanks for your help guys,. any more ideas, let me know. what causes the blms to rise? that might be a potential cause

 

[Red Regal T]

Sounds like it's running on the calpak chip (limp mode). Do you have another chip to try? See if it runs the same with the performance chip removed.

 

[BlackMagic]

I'd guess maybe the computer or chip took a voltage surge when you unplugged and reconnected the ECM, and it fried one of them.

 

[84GNPILE]

Check your PCV line. I've had mine blow out of the intake before and it sounded just like you described..

 

[87gninpa]

im going to try the stock chip right now, but something wierd happened......i let it sit all last night and all dya today and at about 5 oclock i started it and it ran perfect!! took it out for a ride and as soon as i got into the boost after 5 mins of driving, it dogge dout again and went back to the way it was.. i really have no idea, ill try the chip now, but any reason it would be fine and the dog out again? could it be a clogged injector??

 

[MeanBuicks]

I'll put my money on a fouled ignition module (run well cool, act up when warm) or a dying MAF sensor.

 

[87gninpa]

i replaced the chip and its the same. could it be the ecm>? that would make sense since its the only thing i touched while changing the oil..

 

[SouthernCal GN]

Shooting in the dark here-

im going to try the stock chip right now, but something wierd happened......i let it sit all last night and all dya today and at about 5 oclock i started it and it ran perfect!! took it out for a ride and as soon as i got into the boost after 5 mins of driving, it dogge dout again and went back to the way it was.. i really have no idea, ill try the chip now, but any reason it would be fine and the dog out again? could it be a clogged injector??

If if was a clogged injector, shouldn't the stumble be there all the time? Seems to me that it may be more of an electronic/electrical problem.

Runs OK in open loop, then starts running crappy once it transitions to closed loop?

Is it possible that you may have knocked a connector loose while you were doing the maintenance?

Are all the ECM pins intact/none missing? Are they straight, and socketing correctly? Did you 'shock' the ECM when you touched it?

Hope this helps......

 

[87gninpa]

SouthernCal Gn, i think your right about the ecm being the problem. Although i checked all of the connectors and connections around where i was working, i think it may have something to do with when i unplugged the ecm to crank the motor after the oil change. im going to try and find a known good ecm then go form there,. any more ideas? ill go on anything here.

 

[SouthernCal GN]

Check the ground wire at the back of the passenger side head...

Check the fuse block...

Did you pull the negative battery lead before you disconnected/reconnected the ECM?

 

[87gninpa]

no i didnt pull the battery connecter before unplugging the ecm. and what do you mean the fuse block??? the one inside the car, cause if so, which ones should i check>? i checked the ccci and it was fine(only one i tohught would matter for this situation)

 

[87gninpa]

what is the other chip tha ti see in the ecm(the smaller one to the right of the chip)? should i check this as well?

 

[SouthernCal GN]

The fuse block under the dash.

The smaller chip is the calpak (limp-home) chip.

 

[87gninpa]

just switched the ecm for a known good and still same problems. also tried my known good ign module and same thing as well. anyone else have ANY other ideas??? i really need this car to be up and running, its my driver

 

[Roger]

Give the MAF the tap test.
Coil pack.