pro94lt

Guys, I have a problem, I just can't figure it out, my car runs fine in open loop, once closed loop hits it has a horrible hesitation problem and will usually die when you come to a stop, it will idle up then down and die, it acts just like if the float is set to low, I have a new opti, plugs o2's, icm, coil, the thing is it started doing this after I pulled the engine and rebuilt it, I'm really ready to light a match to this car. I've been fighting this for longer than I'd like to say. I'm open to anything. I have my bypass valve dumping about 8 inches past my maf sensor...

first on my list

block off egr
tps

itSSlowZ28

iTrader: (5)

tune maybe?

jaycenk

iTrader: (1)

Check your sensors like the air temp sensor, temp sensor, MAF, TPS, MAPS, and in the fuse box your sensors fuse. I blew mine some how once and change O2's and come to find out the stupid fuse blew. Did the same thing runs in closed and then as I am driving down the street I can barley keep it running.

pro94lt

I'll check all that out... again thanks. anymore sugestions?

idformula

check for codes

wrd1972

iTrader: (12)

I would check the TPS, IAC and the throttle body blades as well. Check for vacuum leaks.

pro94lt

I spent every second of my free time from last christmas till about two months ago trying to figure this out, I've traced every wire twice, replaced 02's, coolant temp sensor on water pump, valve springs, head gaskests, valves, supercharger belt completly took off all piping and inspected, 3 optis 2 were bad, fuel pump, hell since I rebuilt the engine I've had the heads off twice, valvesprings off twice while heads were off it's a living nightmare!!! Not all for one reason. I've done everything I know to do and I'm not new to this, it's been one thing after another but I'm still holding on. I'm gonna cap off the egr, just for the hell of it replace the tps, If this does not work I'm selling the blower, pulling the engine and putting it back stock, the only thing I changed were pistons which lowered my cr and now it has bad hesatation and will surge bad at idle. just hope this car can be fixed, it's so clean, the cleanest 94 I've ever seen and looks to good to be tarped the rest of it's life.

pro94lt

What about to cold of a plug? to low of compression with hot cam?

jaycenk

iTrader: (1)

did you check the fuse? have you data logged it to see what values the PCM is seeing?

pro94lt

yeah, the fuse is good, everything looks good(log). I've spent hours watching all the sensors trying to find a area that might tell me something, only thing that catches my eye is that the o2 mv's drop while its acting up.