JFit728

Ok guys, new to the LT1/C4 scene and wondering if anyone can help out. My father recently purchased a 96 C4 that was running poorly(misfires, etc), but everything was working otherwise(besides having service ASR on dash). So I changed out his optispark(looked original) and also plugs, wires, and waterpump while I was at it. Now after getting it all back together and trying to start it I get no crank, I also have no lights on the gauge working now either besides the "Check Gauges" light(before doing the work all gauges/lights worked). I can see that the gauge(s) are working because the gas gauge is working. It will not even crank/attempt to spin the motor. The starter wont even actuate. Every few tries of turning the ignition I get a weird like "whirring" sound like maybe the starter is turning but not engaging the flywheel, but I've never really heard a starter make this noise. Battery is good as we just bought a new one thinking that was the problem because the old one was really old. All fuses by the battery are good. The confusing thing is the gauges not lighting up/working now since I dont see how anything I changed could have caused, as all the connectors I removed are reconnected and there is really not much wiring around that could have been damaged. Any help on what/where I could/should look is greatly appreciated> Thanks

Whaleman

What brand optispark did you install?

Renfield

FYI, you didn't have to reinstall the W.P. to try starting the engine. I check Optispark performance as soon as it's plugged up.

What diagnostics did you try before the parts festival? Did you run the coil and ICM by Autozone to confirm their performance?

As you are new to the LT-1, you should know that many folks, myself included, consider replacement optisparks a crapshoot. The Mitsubishi sensor in the original is no longer made. A good lead may be the guy who calls himself the optidoc.

Lights out in gauges has me puzzled. Did you have the battery unplugged for the engine work? I would check fuses in cab.

Good luck, and welcome to the fold.

JFit728

Brand is Spectra from O'reilly's I think.

Yeah I know I didn't have to install the water pump to try to start it, but I didn't think I'd have any issues over a (what I thought was)simple water pump, plug/wires, distrib change. The only "diagnostics" done were a code scan which said cylinder misfires or something, I'm not 100% sure as I wasn't the one that did the code reading. The car only has like 80k on it and most of the stuff looked original so I just told him he should change out plugs and wires(which were very old and fouled/gunked up). Waterpump was leaking so I told him to grab one of those and said might as well change the optispark since were down there and it looks like a pain in the *** if it ends up being bad. By the way it did have a decent amount of play on the shaft.

The battery was plugged in the whole time I was working on it and died from the hood lights being on. It was an old/bad battery anyways and has been replaced. I will check the cab fuses to see if that is the issue for the gauge lights.

But seems you guys are focusing on the optispark and not the main thing that has me puzzled is why the starter wont engage/turn over. I get nothing when I turn the key, warning/dummy lights come on/work on center stack but I can't even try to crank the engine to find out if the optispark works or not. I get nothing from the starter except every once in a while when I turn the igntion to try to start it a werid whirriing noise. I haven't had time to look at the starter or mess with it but I don't see how me changing the other stuff would have caused something to go wrong with it.

pacoW

do your lights and wipers work with the ign on, engine off?

Do you have fuel pressure with ign on, engine off?

Easy test, hook one end of a jumper cable to neg battery terminal, clamp the other end to bare metal on the engine, try cranking.

Mr. Peabody

Before you do anything else ........... go to the shop that replaced the optispark and retrieve that original opti with it's Mitsubishi sensor. Even if you have to dig through the trash barrel. The thing is probably still good and if not. can be rebuilt to be more reliable than the junk that is available today.

You say that the old battery went dead because you didn't think to un hook it while replacing electrical components in the engine? The "new" battery that is in there now ... is it indeed "new"? In out cars if the battery is not fully up to charge the car may well not turn over. Make sure this new battery has been load tested and is fully charged.

JFit728

I haven't had time to work on this since the weekend when I changed all these items, as I work night shift.

Head lights work as I checked them when the gauges weren't lighting up. Haven't checked wipers but I assume they do to, will check tonight.

I will try to check the fuel pressure when I have a chance, and will try the jumper cable trick.


I'll pull the other optispark out of the garbage and keep it if it's OE/has Mitsu electronics. The battery is brand new, just bought it during this ordeal, date of 9/18 on it. I should have disconnected the battery but it kinds of slipped my mind.

Whaleman

I believe the opti you took out is worth $70.00 to the optidoctor. I personally would send your original to the optidoctor and have it rebuilt. He does great work. Dan

Renfield

JFit728

Ok, so the issues are the starter won't crank when turning the ignition and the LCD display on the gauges are not working. I have power every where I should. We have power to starter from the battery, but are not getting any power from the signal wire when I turn the ignition switch. Do I need to check for power now from a neutral safety switch or theft system, if so where are those located? Could it be a fault ignition switch?

I don't know how to even go about the gauge lcd display not working, it worked fine before all this. Is there any way to test/check anything?