95 LT1 low throttle mis-fire

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I just bought Mike's 95 firebird formula today. Anyrate, its developed an issue already. Low throttle/partial throttle misfire. When the rpms build over 3k or throttle is more then say 30-40% it runs great all the way to 5k.

It has new plugs/wires, i didnt see them touching any headers but wasnt about to put my hand in there to see if they were tight on the plug (tooo hot!)

When I test drove it, it was cooler out and it ran perfect. COuld this weather be affecting the tune?

[BLKHAWK]

Does it have a check engine light? whats the mass air rate when the misfire happens?

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The check engine light comes on occasionally because of the exhaust (so im told) It has long tube headers, 3" ypipe, borla exhaust, but i leave the electric cut out open because it sounds beast

I can't answer your question about the air flow rate as i do not have a tuner/laptop I was thinking about stopping by an autozone or something so they could pull the codes.

tuned by baker 276whp

[MunsterZ28]

sounds like opti fail mine did that. misfired under load, if you dont have a scanner take it to autozone and have them run the codes, it will set misfire codes

[buttons]

optispark failure? Im new to LT1's isn't that thing a Big B word to replace? If i am replacing it, would it also make sense to replace the timing chain?

edit: what codes would indicate optispark failure, what did you see when you pulled codes?

double edit: car has new plugs/wires. I think im going to look in to optispark replacement, new timing chain,water pump, and a hotter cam ...if i can afford it.

[MunsterZ28]

optispark failure? Im new to LT1's isn't that thing a Big B word to replace? If i am replacing it, would it also make sense to replace the timing chain?

edit: what codes would indicate optispark failure, what did you see when you pulled codes?

double edit: car has new plugs/wires. I think im going to look in to optispark replacement, new timing chain,water pump, and a hotter cam ...if i can afford it.

yes its a pain in the *** to fix the opti. um you dont have to replace the timing chain but if your doing a cam swap its a def must to replace it. the codes that i pulled was just misfire codes on cyclinders, my dad had access to a tech 2 so i plugged it in and took it for a drive put it under load and watched the misfire graph go crazy. i replaced plugs wires and spark plugs but didnt help. finially ended up swapping the opti, ran great for 15 minutes then the NEW opti took a shit. replaced it again. so i would suggest looking for a good brand of opti-spark because i bought a junko ebay one and payed the price by having to do the job twice.

[meissen]

Low Res Pulse Failure seems to be the most common that I hear about. I think it's DTC Error #16?

Honestly, after doing an engine swap twice (drop out and reinstall), I think the optispark replacement isn't really that bad as long as you have it up in the air high enough to crawl under and work on it from below.

Drain all the coolant out of the radiator
Disconnect all the radiator hoses going to the water pump
Undo the belt
Unbolt the water pump - I can't remember which side but I thought it was the bottom right side of the water pump is the one to unbolt first because then it won't spill all over the optispark. You might be able to tell which one is the best one to unbolt first by looking at it.
Disconnect the spark wires, unbolt optispark

Install/put together in reverse order.

Might have missed a few steps, but that's the high level view of it.

[Kwazrollinz28]

Low Res Pulse Failure seems to be the most common that I hear about. I think it's DTC Error #16?

Honestly, after doing an engine swap twice (drop out and reinstall), I think the optispark replacement isn't really that bad as long as you have it up in the air high enough to crawl under and work on it from below.

Drain all the coolant out of the radiator
Disconnect all the radiator hoses going to the water pump
Undo the belt
Unbolt the water pump - I can't remember which side but I thought it was the bottom right side of the water pump is the one to unbolt first because then it won't spill all over the optispark. You might be able to tell which one is the best one to unbolt first by looking at it.
Disconnect the spark wires, unbolt optispark

Install/put together in reverse order.

Might have missed a few steps, but that's the high level view of it.

x2 replacing the opti is a piece of cake to me now after all this BS, just gotta get the waterpump off and harmonic balancer and your set.

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Thanks guys, gotta ask. If im replacing the optispark how much more work would be replacing the cam, water pump, and timing set?? I figure might as well while im in there right?

the cam i had in mind was CC 503 , comp cams? i heard it makes best power on stock heads.

[Kwazrollinz28]

Well timing chain cover has to come off, timing chain, the intake manifold, or your lose your lifters, and you have to undo your rockers.

thats about it from what i can remember,

i know of one guy that did it without pulling the intake, he used some kind of tool that had a really strong magnet to hold them all.

[98blackbeauty]

befpre you go off half cocked I would trouble shoot the problem, you may just go do the opti, water pump, and cam etc and still have the problem.
I would get codes at auto zone, then pull couple of plugs and see what they look like white is lean tan is good and black is oil or rich. I'm not saying the opti isn't the problem but there is a good chance it isn't.

[JoeliusZ28]

I agree with larry, i dont think its the opti. definitely dont put yourself through that headache unless you are sure it is. ive been there done that, just ask brian who is using my old one right now that didnt need replacing im guessing spark plug wires, are they stock or aftermarket?

to diagnose your opti:
http://www.camaroz28.com/forums/showthread.php?t=601565

[mikek18]

It was just recently tuned so it could be a bad plug. I agree i would take it to autozone and have them pull the codes. I feel bad that this happened. and on the first day even.

[mikek18]

It was just recently tuned so it could be a bad plug. I agree i would take it to autozone and have them pull the codes. I feel bad that this happened. and on the first day even.

[buttons]

I tried to get the codes already, but they told me to come back tomorrow on my lunch break. Ill let you guys know what i find, i was going to try and see scott that works at the Napa on plainfield. I know he had at least an 11 second z28 a few years ago -- hopefully he will know what it is.