First of all, I'm about ready to set the car on fire, becoming a money pit.

I had a pcm4less program and i thought that it may be the problem, so I uploaded the stock file and went out for a drive.

All was well until halfway through or so when the car started being a *****. when we first took it out, it would idle pretty well, but when you put the clutch in it would drop then if you gave it gas it would pop back up and hover around 1k rpm.

Throwing 5 ****ing codes:

16: Lo-Res Fail
36: Hi-Res Fail
41: EST Open
42: EST Grounded
51: EPROM/Flash Checksum Fail

So basically my opti and ICM are dead?
WTF is the pcm checksum for?

datamaster file at: http://www.acaenterprises.com/upload/stock.zip

Could both of these slowly dying over the past few days be contributing to my starting problems, idle problems, and dying on the highway problems?

 

I had the same 4 codes minus 51. The car would cut out and the tach bounced all over the place.It almost left me stranded on the side of the road.I had an extra ingnition module tried that it did nothing.I had to change the opti (now on my 3rd I am getting faster everytime) and car started right up.I can't help you on 51 execpt maybe clearing the codes and see if it comes back.

 

So what has actually broken/blown up/cracked/dented/whatever inside the opti?

 

i swear this piece of **** has a mind of its own. it idles pretty damn well in teh garage, i just wnet out and started it , took a little while to start, but it did.

 

When the opti or the wiring to it has problems, it can manifest those other codes. I've seen it posted many times. Check the opti connections, if no problems are found, your opti sounds on it's way out (dying when it gets hot).

 

The first one went because of moisture it was all corroded inside (nonvented 94).I made the mistake of replaceing it with a rebuilt one. It only made 2 weeks before it crapped out and it gave the symptoms I said before.I replaced it with a new AC-Delco unit. You can get from www.samtaylor.com ask for Jason he quoted me $288.00 plus shipping.Also the 94-95 are known for problems with the coils also.If you replace the opti make sure it starts before you put it all the way back together.All you need it balancer on the motor and hook up all the sensors.I just laid everything on the side out of the way.

 

shoebox, what do you think is dying inside the opti? Has the high voltage been PROVEN to destroy the opti or is the ozone myth a theory? cause i'm looking at the LTCC here and it seems to be a pretty good deal, including a spark limiter and a retard function, cause i plan on juicing in the future.

 

Rob, I am wondering if the ICM is the cause of this? I have it spaced away from teh head so it can cool a little easier, but it would only seem logical to me.

can it cause the low/hi res codes to be thrown? b/c I cant see the the opti functioning different if its hot or cold, but the icm i could see that? just a thought.

and how come these codes dont set the SES light if they are so vital to the cars performance? Just another great GM engineering feat?

 

I can't answer why it does not light the SES<shrug>.

I don't think the ozone is a myth, though the opti is susceptible from other things as well. Because it has electronics in it, heat can also be a contributing factor, just like with the ICM.

I was just reading in the factory manual and it says if 41 and 42 accompany 16 and no external fault can be found, then the pcm is suspect. Pcms don't die that often, but what I would do is check all the connectors and pins on it as well as the opti harness. Make sure you don't have any ground leads anywhere that are not secured.

 

Its stupid that it doesnt light the SES up....

Im wondering if this checksum thing is causing hell? Cause i uploaded the stock program and then all this **** happens.

you say 41 + 42+16 = pcm problem, what does the checksum have to do with it? Maybe that is causing something?

I'm gonna go scan the car here at idle and see what it comes up with.

 

man it idled great just now! didnt take it out for a drive, but idled it in teh garage and it ran nice.

http://www.acaenterprises.com/upload/pos.zip

Wondering if something got messed up when programming the pcm? cause it gives the checksum error and you say that when those 3 are thrown it points to pcm..... hmmmm

 

als owhen i did the above run, all teh codes are still there.

 

I was just laying out the possibility of the pcm-not saying that is the problem. Like I said, I have seen many posts with people getting the 41, 42, 51 code with a bad opti. Looks like the pcm can hiccup sometimes when certain things are going on. It may or may not be the source of the problem.

As far as the codes still being there, did you reset the pcm? Re-programming it does not reset the volatile memory from what I have observed.

If you think the programming did something, take it out for a test drive.

 

DAMNIT WHAT THE ****!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!

reset the pcm by pullin the fuse, codes went away, went for a drive. idled find for a little, once it gets warmed up, any chance it can get to die with the clutch in, it will. shift slowly and it will die.


Now there is something clanking around in the intake or the valve cover....gotta let it cool and see wtf that is....

 

Scan again and see if you have any codes. Maybe you have a trashed opti and it is clanking.