Odd Running Dsm 2000-4000 Sputter And More!

dumb_ricer · 04-21-2004

Alright, so my friend drives a 92 Laser AWD 5sp. Current mods are Ported 14b w/ 34mm flapper@14-15lbs of boost, k&n, open stock downpipe, and thats it i think. Well since he got it about a year ago it has had a odd sputtering problem from about 2k to 4k only when the motor is under load, the more load the worse it gets, almost feels like a misfire, but only when not under boost and on it a little. Another thing that *I* have not experienced after driving the car for about 2hrs over the past 2days, and not taking it easy on it either, is that it tends to die whenever he brakes he said. When I got in it tonight I pumped the brakes right when i got in and revs dropped to like 5-600 but they went right back up, so i dont think thats much of a problem. We have done plug wires, plugs twice, checked base timing, made sure everything was plugged in, and still it does that. Any other possibilities of what it could be? After it gets into a little boost it pulls like a DSM with his mods should pull. But even after each shift it tends to not want to go for a second then it puts you back in the seat again. No, I do not shift slowly, and it isnt the turbo as far as I can tell, as its happened with both of his turbos. Any more questions just ask me. Thanks for any help in advance!

john · 04-22-2004

Is his MAS plugged in? The car will feel pretty sluggish if it isn't. Also check for vaccum leaks. Does he have a venting bov? That will sometimes do it also.

**Kracka** · 04-22-2004

If the MAS wasn't plugged in they would be getting a CEL, which I assume they are not since it wasn't mentioned. Besides the leaks and BOV that John mentioned...is the o2 sensor cycling properly during open-loop mode?

TheBlizzard · 04-22-2004

Have you checked for boost leaks? If you have changed plugs, wires, ect thats the next place you should go.

CRAIG

santa · 04-22-2004

when he first got the car i changed the plugs and wires the mas is pluged in. im wondering if his computer is done for? i have a spar i suppose i can through it in and see whats up and also check if the timing is on or not...

john · 04-22-2004

If it isn't anything listed above, my next guess would be the ecu. If you have access to another, may as well try it. A unplugged MAS does not always pop a CEL atleast on a 2g gs-t. It made the trip from Hopkins to QPR without a CEL. The car just felt sluggish. Ghettostyle's 2g AWD on the other hand will not rev past 2000 rpm without the MAS plugged in. Depends on the car I quess...

dumb_ricer · 04-23-2004

The MAS is plugged in. It has been unplugged and plugged back in many times since he got the car, and it has been a problem since he got it. I'll have to try a new computer, and check for vacuum/boost leaks anywhere in the system.

SuperSleeper · 04-25-2004

Quote:

Originally posted by 92tsiawd84@Apr 22 2004, 08:56 AM
Does he have a venting bov?

^^^

dumb_ricer · 04-25-2004

Umm, no it is not venting, its dumping back in.

Jacek · 04-25-2004

maybe the maf is starting to take a dump. switch those and see if there is a difference.

santa · 05-10-2004

*UPDATE*ok so I did some more work on the car and well here are the results. I put one of my good computers in the car. checked the timing and checked the plugs and wires to be sure there in the right spot. well that didnt help at all. the mas is good still. Im thinking maybe a fuel pump issue possibly needing to replace his? or at least re-wire it? idk leave some insite please?

1Fst14B · 05-10-2004

what were the results of the boost leak test?

santa · 05-11-2004

there were no leaks at all

05-25-2004

Did you check the IAC? my 2g was having issues with Idle and riding up high the dropping and such. took out the IAC and swaped in a new one and it has solved the problem.

my 2 cents worth

-Tim