odd problem??
 

for the past few days, whenever i start my car first time for the day and let it warm up, i would drive it wherever i need to go and as im doing that i feel it stutter a bit whenever i partially give it throttle.

i also have a air/fuel gauge hooked up in my car so whenever it does this stutter it would just light up.

also, when stuttering (especially at night) my lights just flicker a bit. now this doesnt seem very healthy at all.

what do you guys think it could be?



!!!
my car is a 1990 TII w/ jspec motor - no emissions - BOV - cone intake - fuel pressure regulator - external wastegate - 3 inch full custom exhaust and im pushing out 8psi.

TPS, maybe?

actually previous before this incident, my TPS was acting up also. it was bouncing at 1500rpms most of the time during the holiday weekend. it hasnt done that since then though.

grab a multimeter and plub that bitch in to the TPS and see what readings it gives you!

my car does this too and the tps is fine.

sounds like loose Ground if your lights flicker too

update :: well today i started my car....took a little long than usual till it fired up. i backed out of the yard and as i started through my neighborhood, my car ran like shit. ran like that for a while but then it started running like normal. and then when i came to a stop light, my car stalled on me and so i restarted it and as soon as that happened it starts backfiring.

so now i limp into a parking lot and let it idle for a bit. as its doing this i notice my temp gauge start to flicker around also. the needle somewhat pulses with the pulses of the engine but rising. i turn it off and turn it back on and now my gauge sat steadily at the halfway point.

now i try to make my way back out of the parking lot but as i do so my car is struggling and backfiring again.
sit awhile and then fire it back up and now it seems to run fine...although when i try to take it into boost it stuttered a bit.

anyone who knows what this may be please let me know!! and hopefully this isnt the sign of a dying engine!

btw, i was told i may be running rich...my fuel is set at 60-65psi with stock injectors.

Why you running 60 psi with stock injectors?

let me go double check and find out.

actually i just checked its at 50 psi

soo...is that fine?

Injector pressure per FSM is something around 32, unless you're in hot start mode...

Unless you're shoving in the air to go with it, I'd say you're probably shoving excess fuel into the engine that it can't possibly use- hence the "stuttering"...

stock boost is 6psi so right now im at 8psi. i assume the raise in fuel pressure is compensated for the increase in boost.

but then again, last week this car ran great. it didnt run into this problem until sunday

Ahh, another one of those turbo guys...In that case, disregard all of the above, I have no idea what rail pressures you guys use, nor do I want to guess...

How well can you troubleshoot the sensor inputs at the ECU, to rule those out?

Any codes? Could be a ground, too...

troubleshoot? uh...im not really familiar with troubleshooting any ECU codes yet.

as for a ground....thats what im thinking so far

OK, for starters check out the one on the rear rotor housing, upper left side, below all the junk up there. That's the important one, along with the tranny-to-firewall bonding jumper.

Start reading, Haynes, FSM, forum...If you don't learn how to troubleshoot, this car will kick your ass....:)

we're talking about a ground right? if so, then its very well hidden somewhere there.

bump, i would really like to try and figure this out myself before i have to resort to a shop

This seems very similar to a problem that I am having with my 86 GXL. So, it may not be something related to your turbo. I would put a timing light on your wires and check that your leading lines up with the yellow and your trailing lines up with the red mark on your e-shaft pulley. I found that I was not getting spark from my trailing coil pack, so I replaced it...the problem was better, but not fixed. I then replaced my ecu, as they can have blown or leaking caps. No change. I then replaced my crank angle sensor...again, it helped, but did not fix the problem. I am now in the process of dropping my dash and rebuilding the harness that goes through the fire wall on the D side and over the tranny tunnel to the ecu. My car's previous owners had stereo and alarm equipment installed and the wiring is a nightmare under there. So, I am pretty convinced that the problem lies in that harness or a GROUND that I can not access from the engine compartment.

Check out your ignition system and make sure your grounds are good. Also, have you gone through your grounding for the 3800 rpm hesitation??? Make sure those are good. I hope this helps...if not I will update you on what my problem ends up being

Hmm, my car has started hesitating at 1500 rpms with light throttle when it's cold, feels like driving a car with a TPS set incorrectly, but mine is reading correctly, and the hesitation goes away when the car warms up.

Now I'm getting worried, heh.

UPDATE!

just replaced the trailing coil ignitor. it looked like it was fine for a bit but then again as i put it into gear, same shit!

this is getting very frustrating!

When was the last time you changed your fuel filter. Just a thought

come to think of it...never since i bought the car.

is there a way to check if the ecu is good?

My opinon....I think it is the ground wires. Well, my car did the same thing.... sort of...
it started to not start... or starting slowly.... then when i put it in reverse, my headlights flicker and dim..... then my idiot light cluster came on.... like i was stalling....

next morning i was driving on the freeway..... and it started limping at 80 miles per hour!
Later i noticed the MAIN fuseable link blew...... and i got it checked out.... it was my engine ground wire problem..... the ground wire was bad and it was also shorting..... and the last owner had 8 or 4 gauge (i forgot) ground wires so i grounded the engine ground to the frame and everything is fine now =)

I say check the ground wires....