James Montigny

iTrader: (13)

The stud on the fender.
The only thing on the battery should be the cables that connects the battery to the stud, block and starter.

I don't know if the big3 would solve the problem.
It really depends on where the grounding issue is (sensor to block, block to chassis, chassis to battery).


While you're in there looking around, make sure that the wiring harness isn't
cut or melted somewhere between the ICM and the back of the intake.

95chevyz28

I did notice this. Not sure what exactly it is. Probably doesnt have anything to do with my problems. I did get a pic of it. It got burnt a little on the exhaust manifold.

1961ba427

iTrader: (26)

That is a check valve in the opti-spark vac harness. You definately want all that stuff working right to keep moisture out of your distributor. I was having similar issues to yours and it turned out to be a few bad plug wires. One of them even looked perfect, but it didn't ohm out well.

95chevyz28

well i still havent had time to look at the grounds. I was sent out of town for work for a week. I am not getting a misfire code so I dont think its the plug wires.

9transam6

I am having similar problems I am posting a thread about it. Not sure if it will help you 95z seeing that I still have the problem. Check out what I have been thru and see if it does.

9transam6

My post-Missfire in 96 TA
9transam6

1961ba427

iTrader: (26)

My car is a 97, but I'm running a 95 PCM and obd1 now. I didn't get any missfire codes either. I don't think you will with any 95 and earlier car.

9transam6

How hard was the convert to OBD1

Ictinik

I would check the harness, all 3 codes you have come out of the same leg of the harness, maybe it fell against the exhaust and got burnt or something, To have a MAF, IAT, and Ignition controls code all at the same time leads me to believe that there is a wiring issue

1961ba427

iTrader: (26)

It's cake. lol PM sent

95chevyz28

well like someone else suggested, i will be looking at the ground wires. I might even put a extra one in just to see if it solves it. What could cause it to intermittenly do it though? Like i have said before, sometimes its fine. Once i bounced it off the rev limiter because my trans **** second gear and it did it soon after. If its not the grounds then im at a loss as to what it is. I wont be back till late friday so hopefully saturday morning i can take another look at it.

Rg591

keep us posted i have the exact same problem and ive replaced basically the whole ignition system and it still misfires i was hoping id get some ideas from here lol

iWon

iTrader: (13)

It sounds like you have a wiring issue. It very well could be the Optispark as well though.

I am having similar issues with my 93... it will drive perfectly fine sometimes, then out of the blue shut off or backfire. As soon as you get on it it runs like ****. I'm getting codes for Faulty High Res Signal, and Lean Exhaust. I'm 90% sure it's the Optispark.

95chevyz28

Im thinking its the opti as well. It has a new cap and rotor but the distributor part has 135k on it. I am going to clean the grounds tomorrow and add another ground wire. Figure it cant hurt anything. I will keep you guys updated.

95chevyz28

Also forgot to mention that after the car has been running for about 20 mins, if i quickly jab the gas, i can see the voltage and rpms drop ever so slightly. On a cold start, if i jab the gas, the throttle response is instantanous. Could it possibly still be the alternator? Can I test it while its on the car? If so, how? Im assumming with a multimeter. Thanks

95chevyz28

hey i was just looking at shbox's website again. The one pic he has of the coil, is that a ground strap going to one of the bolts that hold the icm to the block? If so, it is missing on mine. Where do i connect it to on the frame from that bolt?

95chevyz28

ok so i added a ground strap to the one bolt behind the icm to the frame rail. It hasnt started acting up again but i havent really driven it far since im scared i will get stranded somewhere. It is popping out the exhaust on occasion. It also seems that after the car warms up, it idles really low like 650 maybe 700. Like for instance, a few mins after i started the car up, i slammed the gas and it took off like a bat outta hell, spinning the tires all the way through first. Since my second gear is gone, i had to let off so it wouldnt bounce off the limiter. Then it backfired(popped). After another 20 mins, i get on it again from a stop and it seems like it hesitates for a split sec and then goes. It wouldnt even break the tires. It climbs nice and smooth though. Im really leaning towards the opti. If not that what else could it be?? Thanks

iWon

iTrader: (13)

Once again, my car does the same thing... when it drives "fine" it's still not as responsive or it will hiccup occasionally then go. Bad opti. I'll be getting another MSD this week under warranty, I'll post up after I install it hopefully it will fix my issues.

stephanj51

iTrader: (1)

I'd che k the plug wires for a burnt one or see if u switched one

iWon

iTrader: (13)

He's said like 3 times the wires were recently replaced and they all look good.