my car started missing and popping when it got hot seemed like the opti so i replaced it twice with new gm ones to no availthen tried the coil and coil wire checked the grounds then car started holding the injectors open for like 5.3 ms at idle so i send the ecm out and everything checked out ok was just wondering if any one else had similar symptoms when their harness went bad..... please list your syptoms

 

Have you ever had the PCM scanned for codes? You should get a flashing SES light for misfires, and you can recall the actual misfire count by individual cylinder, to determine if its specific to one or two cylinders, or truely a "random" misfire. The Opti will also set codes for problems with the high and low resolution pulse signals, and that's what has to pass through the Opti harness. Recurring problems with P0372 or P01371 would be a sign of a harness or an optical sensor problem.

Have you ever checked the IC Module? Not uncommon for them to overheat and cause problems similar to what you described. Shoebox has a procedure for spacing the ICM off the cylinder head to reduce heat soak.

Not sure if I got close to answering your question..... it REALLY makes it hard to understand something like that with no punctuation at all.

 

sorry never did good in english class LOL. Car has not thrown any codes. Car runs open loop tune only. MAP is a little high. MAF readings are good. ICM would not cause the car to hold the injectors open for 5.3 ms at idle. Bryan herter gave my pcm the once over and found nothing wrong with the drivers in it or the tune. Tune ran good for 500 miles then this problem started when the car got warm....now it does it all the time. At first seemed like opti but then the car started holding the injectors open WAY too long. Hope the punctuation helps LOL. So i was wondering what kinda symptoms people where experiancing when the opti harness goes bad. Doesn't the opti give a resolution pulse to the pcm for injector firing???/

 

The PCM uses the low resolution pulse to determine the firing order and timing of the injectors and the ignition. Without the low res pulse, it can not run the engine. A faulty harness will typically cause codes for high and low resolution pulses. There are codes that will not turn th SES light on. You can't assume because you have no SES light, you have no codes.

Injector pulse width is set by the PCM based on mass air flow and the "learned" long term fuel corrections (BLM's). The PCM will richen the mixture (longer pulse widths) with a faulty signal from the coolant temp sensor, or the MAP sensor.

I guess the punctuation thing is just a big "LOL" to you, but I can assure you it affects whether you get a response, or whether the response you get is accurate. I was trying to help you get better results..... but since I seem to have upset you, I'll leave you alone.

 

Being a little oversensitive, aren't you? I don't see one sentence where he was "upset" with you. Bad day or something?

 

I'm not sure about him, but if I start reading a post, and I get confused by bad spelling and/or no puctuation on the first line, I skip it and go on

 

i wasn't upset at all. I just didn,t realize that a period or some commas could make that much of a difference. It made sense to me when I read it. Sorry if I came across as being upset, because it was completely the opposite. I always appreciate the help.

 

I did not know we were back in school
Any how... My opti harness is in bad shape, I do believe that it has effected the performance. I say this due to the fact that the engine has a miss, mainly on humid or rainy weather, because the wire harness has cracks on the insulation.
I think that the moister in the air is causing the wires to arch or something.
I should be replacing it soon, and I will report any changes.

~Greg

 

That's fine. It has nothing to do with that. It has to do with Fred thinking the guy was upset. Nothing in his post specified the guy was upset.