The past few months my car has been running like crap. It all started when my car started misfiring on my way to school, not bad but got to the point where it wouldn't even start. My dad thought it was the fuel pump for some reason, so we replaced that with a Racetronix. No start. So finally we dug into the opti-spark and found out that the wiring harness and tower was crumbled to pieces. I didn't have the money at the time so I just replaced the opti and not the cap and rotor. Then came x-mas break and I came home from school for a while and decided to work at one of my old jobs to make some extra cash. On my way home from work the metal part of the rotor decided to come off and died on me as I was pulling into my driveway. Car ran fine after we replaced the cap, rotor, plugs, and wires. On my way back to gainesville the car started to "buck" for lack of a better word anytime I would hit 3k rpm, anytime before or after it ran fine. When i say buck it felt like the car would hit a brick wall and then accelerate fine. It did this for a while, I talked to one of my buddies who just got out of UTIs mercedes programs and he told me to unplug the front O2 sensors to see if the car ran fine on open loop. And it did for a good week. Then the car started "bucking" again. And the past two days the car has just been dying in traffic, or just while I'm cruising down the highway. When I try to start it back up it sputters and pops and dies back down. Then today it just completely died on me and wouldn't start back up.

I was curious and checked to see if there was any pressure building up in the fuel tank and I unscrewed the gas cap and no pressure "came out." So after I got my car towed back to my apartment complex I decided to pry open the doggy door I made for the fuel pump and check all the fuel lines, evap lines, ect. Checked the sender to make sure it was sealed in the bucket and all the connections were fine along with all the lines. So I moved up to the engine. Checked the shrader valve and very little fuel came out the first time i pressed on it. Primed the fuel pump again and pressed on it again and got a powerful shot of gas to come out. So I moved to the opti and all the connections and everything seemed fine along with the ignition coil. Decided to "ghetto" test and see if a plug was getting any spark but pulling it out and letting it rest on the fender well for a ground while trying to turn over the car and could not see any spark going to the plug (this was at night).

 

I've never had any luck rebuilding opti's, I would just replace it. If you wanted you could actually go through and ohm out the coil and ignition module to make sure that everything is ok there, but typically the opti is the problem on LT1's.

 

Check your Coil again, or the Ignition Control Module.

 

try the opti spark harnes that is what it was on min e

 

I've had problems with the actual connector for the opti being bad;had to make a pigtail to fix it. Electrical sucks!

 

If you have a buddy with a similar car, you might borrow the harness pigtail that connects to the main harness, passenger side, about halfway forward, next to the intake manifold, the other end plugs into the Opti. I kept one of those and at least one high tension coil wire on the shelf for LT1 cars when I had my tune-up shop open. Also, I wouldn't bother trying to repair an Opti, nor buying one from some place like Autozone. As a mater of fact, I would never buy anything from Autozone that had a wire connected to it.
Even though I own stock in that company, I only buy certain things there.
If you buy a new Opti from the GM dealer, be certain to clean the rotor mounting screw, and put red Locktite on them, and snug them properly. They are never tight enough to stay like they come out of the box. Don't worry about the red Locktite, the screws will still come out if ever needed.

Good luck, Ed

 

Yep as everyone stated I wouldnt try to rebuild an Opti nor use a remanufactured one. As Ed stated make sure you tighten the rotor screws because I didnt and mine fell off within two weeks It didnt cost me anything to fix it but as we all know getting to the Opti isnt all that fun.

 

it was either the ICM or the Ignition Coil. Went through and tested all wires with a test light and all problems led to one of those. Didn't want to replace one and see if it worked then try the other so I just bought both and got on with my day. Thanks for all the help guys

 

lol so that lasted not even 20 miles and it's back to doing what it was before. I guess it's time to tear into the crapti-spark.

 

BTW when it died on me tonight it was backfiring like crazy and sounded like the engine was about to blow up

 

just curious, when was the last time you changed out the fuel filter?

 

when i changed the fuel pump

 

The one thing you havent mentioned is if you have checked the connectors real well. When I say check them, I mean look at the female connector pins real close. they have a habit of "opening up". I've seen it countless times. You're probably fixing it temporarily each time you unplug and plug something. if you use a small, bent dental pick, you can get the pick behind the "tang" in the connector and bend it back in just slightly. Dont it probably hundreds of times by now. Dont know how easy it would be for someone with no exp. doing it.

 

i think it might be something a little more serious than a connection being bad with the way it acted last night

 

Im stumped, is there any check engine light on? check the altenator to make sure its not throwing too much juice causing other systems to eventually fail... just a thought

 

So I just got the opti, cap, and rotor out again. Everything seems to be perfectly fine. I mean you can't tell if the optical sensor is ok or not just by eyeballing it (at least I think so unless one of you guys tells me otherwise). There is some oil leaking in there, but I just replaced that seal when I put the cap and rotor in there. But talking to mike norris from Next Level Performance he tells me that what I did - putting an opti in at a different time then the cap and rotor can be bad and lead to ruining the ICM and ignition coil and so on. I'm really at a "plateau" as one would say in weightlifting, in terms of what to do next or where to go to figure this problem out.

There is an SES light but thats from the EGR and from not having a tune (which I need to do ASAP once I get this thing running right). I don't know any close friends or anything with a OBDII scanner either. And like I said I'm stumped too.

 

Honestly sometimes i would just suck it up and take it to a dealership. The money your going to probably spend is going to end up being less in the long run of you just throwing parts at it. And if they fix it and something goes wrong you have room to bitch and probably wont get charged if it has to go back again, because they didn't fix it the first time.

 

believe me man that is what I want to do. But my father is the one helping me out with all of this (financially) since I don't make nearly enough money while being in school to worry about this and pay rent and food and all that. And with him being a mechanic for 20+ years he never wants to take anything to the dealership. That is really what I wanted to do this time, but I can't argue with my dad who is willing to help me with both labor and finances. If something else breaks while I'm at school I'm getting it towed to the dealership tho

 

Ok so we got the car running now. Now the car will run strong for about 10 miles or 15 minutes and just shut down/die on me. Wait about 20 minutes to let it cool down and it starts back up and will run for another 10 miles or 15 mintues and then shut back down.
Talked to someone locally they said it could be the coolant temp sensor doing this?

 

You'd be surprised what a bad connection would cause. And, bein as you've replaced all the critical components with no luck, I wouldnt be so quick to discount it... Its a classic case. "I replaced such and such cause it had a code for that and its still doing the same thing and still has the same code." Not saying that this is exactly whats wrong, just that the importance of the condition of the connectors cannot be overlooked. You will spend in vain repeatedly.
PS This info isnt coming from a DIYer working in his garage. I do this for a living. I diagnose problem cars for other pro shops in my area. You would be surprised at what some professional techs overlook. Remember; ATTENTION TO DETAIL