i brought the car to a dealer (BIG MISTAKE!) who said they would do the swap for $255, and ended up charging me $750 . (DON'T GO TO KING GMC IN PUTNAM, CT!!!!!!!!!!) that aside, the car now runs like its on 4 cyls, its got no throttle response, feels like its about 100hp, and backfires (LITERALLY) once per second on the highway. i can no longer make it up my friend's driveway without being in 1st gear (and i have a 4.56 rear end.. i used to be able to go up it in 4th or 5th).

the dealer checked the firing order and said that they think its because there is oil on my wires, but there was oil on them before, so i don't see why i'd go in there on 8 cyls and come out on what feels like 4....

they refuse to admit that they could have done anything wrong in the optispark install...

anyone have any ideas? it feels like the car is in a constant state of having -45 degrees of timing or something, and is firing waaaay off from when it should be. it runs predictably (not erradic, no sudden hesitation, just cosntantly running the same way, BAD).

you can hear what sounds like a constant miss too..

im afriad to drive this back to NY to have a trustworthy mechanic look at it, cause im afraid i'll have a big explosion on the way back due to all the fuel building up in the exhaust.

i guess if you want something done right, you really do have to suck it up and do it yourself

 

I don't care what they say, I would be back there in a heart beat telling them I dont care what the F is wrong, just fix it!

 

they said to replace the wires and the ICM.

i told them they are idiots because the icm wouldn't do this, it would either not work at all, or fail like crazily on all cyls..... not misfire in some constant manner with these kidns of symptoms..


and the wires haven't changed sincei brought in the car, why would it run fine for 6 mo, and have the wires simultaneously go bad AFTER i brought the car INTO the shop.. even when the opti was going, it was running on all 8 when it did run...

I HATE SHADY MECHANICS

 

Maybe a few crossed wires when they put them back on the opti? I'm no expert but just giving you something you can check easily yourself. Either way let us know what happens.

 

they charged me an hour just for "checking firing order" when they originally did the job. then when i brought it back today they claimed to "recheck the firing order"

they'd have to be pretty big idiots, but i still want to check it myself, its just that the passengers side is so damn tough to even check.

i checked the drivers side, and they were correct.. i'll let you know..

 

I wouldnt pay them another dime until its fixed the right way. If it were me, I would cause the biggest damn scene and get the manager to admit there is a problem with the car. BTW, I did the nice thing before and they just shrugged me off, then I came back a few minutes later with a few F* bombs ranting and raving and the other customers were scared to death. Apparently its bad for business They fixed my car though.

 

They might have installed the opti wrong.

 

how could they install the opti wrong? the only way i can think of is flipping the disc upside down but that should be a red flag that the holes don't REALLY line up.... like you can force it together, but any mechanic worth his weight in water should be able to figure out how to assemble that thing...

though.. if it were put together wrong, it would be like 20-30 degrees off in timing, i think.......

 

go back and cause a big scene, because for 750 dollars they better have that thing running smooth when you drive out of there.

 

it does sound like the opti is off. i live in putnam and now a couple of the mechs. and the parts and service guy.id be happy to help you out if you need a hand

 

Can anybody look at a datamaster file? my Right side LTerms are at 160 constantly, it doesn't seem like it should be lean at all, with the ammount of fuel in the exhaust, and the backfiring. There's no knock detected or knock retard, which is contrary to what I was expecting... there is actually a bunch of spark advance like usual...

I guess im worried about faulty O2 sensor readings, but I have no idea whatsoever why that would fail only AFTER i brought the car to their shop (as I drove it in, it was running like a top).

Does this seem more like crossed wires or a mis-timed optispark to you guys?

Of note from the SOTP, at idle, its REALLY rough, at around 11or 1200 rpms, its a lot smoother, then as i continue to rev it up, it gets rough again, then smooth again, in a seemingly sinusoidal manner, with respect to RPM...

 

i accidently had 2 wires backwards, i noticed it right away once i sat in the car. i drove it about 15 ft, then i stopped as i knew something was wrong. it didnt backfire, but i think that was because i had barely gave it any throttle at that point.
symptoms were rough idle and tach jumping. also sounded terrible. just a thought.

 

here's the datamaster file, if anyone can take a look:

http://www.cs.rpi.edu/~roghab/datalo...-evil-king.uni

Thanks in advance

 

If you post the Datamaster file in ".csv" format, rather than ".uni", people without Datamaster can read it using Excel.

Your spark advance readings in Datamaster are the values the PCM looks up in the tables based on RPM and MAP. Even if the Opti was on backwards, those values don't change.

Misfires cause it to run very rich.

Since you have a 95 with a vented Opti, its not as likely that the Opti was misaligned with the cam dowel pin. It is actually quite easy to assemble it with the pin in the wrong hole, contrary to popular belief. The error is a big one though... 120 cam degrees (60 crank degrees). Again, even if this happened, Datamaster will still show the same values for spark advance, since the PCM is just looking the numbers up in a table.

What was the original problem you had that caused you to have the dealer replace the Opti? Was it an any way similar to what you are getting now, with the new Opti?

 

The original problem was that the opti threw DTC-16 and DTC-36. There was oil in the opti that leaked past the wet-pack seal on the opti harness.

The car ran like a top, but suddenly the tach would jump around crazily, and then the car would stall (when the code was thrown and the car cut fuel pressure).

It ran like a high 12 second car even just as I drove it into the dealership parking lot (aside from the random tach / stalling episodes).

When i picked it up it was backfiring, and had the constant misfire, and felt like a 20 second car, haha.

I'll try to repost that in .csv format. Thanks for looking.