LT5

I replaced the optispark recently and i still have gotten a very rough high idle, when car warms up goes down to about 900 or so, checked for vaccume leak, entire new fuel system, new plugs new wires, new opti, new tps, new map, new o2 sensors, new map sensor, fixed all bugs and wiring issues, cleaned air filter, new fuel filter....im thinking at this point i must have a bad timing chain, car has 130k miles on it. Not sure how to check for this but car still will not start, no codes...

mrmint69

It doesn't sound like have enough miles to be worried about the timing chain. Did you do all the maintenance stuff listed after you developed the idle issue? I had an issue similar and cleaned the maf sensor and it fixed my problem. Have you done this recently? It could be something simple like a plug wire to close to the exhaust manifold or a spark plug issue. When you say won't start what is happening? Does it crank over but not fire up? Have you verified fuel pressure? I think you can get codes even if it won't start. I believe some won't throw a dash light.

LT5

I just put a new maf on it, new everything, cranks but no start with hard smell of fuel, opti is a jegs unit only 2 months old. I will say though that the plugs and wires are about 3 years old, i messed that up in my post. Will be doing those today....hopefully all goes well. If not im at a loss for what it could be.....ive basically replaced everything. Last time i did a tune up i could not get to number 5 which i kept the same plug wire and spark plug in, maybe this could be a huge part of the issue, i got new msd super conductor wires, new exaust gaskets, and new e3 spark plugs....hopefully all goes well. Ill keep this updated.

mrmint69

I would definitely recommend checking for any codes with a scanner. You might be able to pin point the issue without guessing. Do you have any way of doing this? What's happening when you try to start it? Does it just crank over strong and never fire up?

DrewHMS97SS

One old plug that is not the same as others could be the issue, but I also would not recommend E3 plugs, go get a set of Autolite or NGK plugs. Also make sure they are all gapped evenly.

LT5

Well all plugs wires done, new copper exaust gaskets also. Thing didn't budge, put side computer in still nothing. New timing chain a cloys heavy duty singe, and new jegs optispark.....will have an upday soon.....she should run damn good after all this.

LT5

Ok update new opti, new everything timing chain, car fires up but idles around 1800 or so and won't go down, new tps, new idle air control vavle ext.....map sensor new, maf new, ext....not sure wtf......

Injuneer

Did you consider running a log of the PCM to look for problems? A lot cheaper than random parts replacement.

mrmint69

You have replaced a lot of parts and probably most of them were unnecessary. I hope you follow the advice given and do diagnostics for the moment and wait to see what's wrong before moving forward.

LT5

After all was and is said and done, it was the pin connectors on the optispark that caused the no fire, 2 spark plugs that were cracked and a half burnt wire lol. Also the idle was still super high when the shop was done with it, after 2 more hours of looking at the car, they realized there was a bad tps......which i just replaced 2 months ago.....had to pull the tb off and basically redo the idle. Car runs decent now, fires right up after about 2 seconds or less and sounds different. With the e3s, msd wires, new opti from jegs....fires right up. New timing chain which was not needed but now i won't worry about that for probably the life of the motor. Only thing is it still moves the idle just a tad here and there, no backfiring, no studduring or anything of that nature. I do have a pcm for less tune i got over a year and a half ago, and he tuned it for no maf screens, i was wondering cause i put new maf on and it has screens. It is also a autozone one there brand duralast. I think once i descreen the maf or get fast toys maf ends it should run like it did when it was stock, i mean shes at 95% now so.....im hoping thats all it is.

mrmint69

Sounds like your moving in the right direction. I usually replace one part at a time. If you have replaced several and something goes wrong you never know which one was bad. Seems like you are really interested in getting this car perfect. I got a cable that hooks to my laptop. I drive around around and record the vehicles data. If you have something like a bad O2 sensor it will tell you. Best investment for the price. Did you ever find any codes?

LT5

Tuner cats? Yeah i am going for the bolt on record eventually but ive replaced so many parts its gotten in the way. I would say in one more year i will be able to get to the dyno or this summer and give it its first good pull. Im sure it will get about 300Rwhp and some good torque. I still need a bunch of performance parts to get to that 340+ range that im shooting for all bolt ons no heads no cam no intake ext.

mrmint69

My goal was high 12's with stock motor. It's fun to run with the new Camaro's and have only spent $12 including the car. Doing most of the work myself has really made it worth all the time and effort. Don't waste your time on all the worthless mods that's are cheap and really don't do much.

LT5

Im thinking electric water pump, ac delete, power steering delete with manual rack, basically all accessories delete. Then fast toys maf ends, with a different intake then the k and n. After that its just digging into the tranny, thought about selling the 6 speed for a built tk0 600 5 speed and doing aluminum flywheel and carbon fiber driveshaft. That alone will all be worth a solid 20+ rwhp and give the car a much faster take off with those parts but thats much further down the road.