No Spark No Pulse???
Thread Starter
2nd Gear
Joined: Feb 2018
Posts: 2
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No Spark No Pulse???
I have a 94 vette and it has no spark no injector pulse its been sitting in my mechanics shop for weeks now and its becoming a lost cause... It has a 1yr old optispark, new plugs, new wires, new MAF, new Ignition coil, new Ignition control module, we both suspected ecm so i sent it in and it was repaired... stil nothing. Its so random he has a noid light hooked up to one of the injectors and when it doesnt flash it will just crank and crank no start, sometimes the light just starts to flash and it starts and runs fine (light still flashing) no skips no stutters then a couple mins later the car just dies out of nowhere! It just like someone flipped an off switch and the engine stops running and then the car wont start and the car wont have pulse or spark all over again. Could this be a loose or corroted ground wire? Or perhaps the MAP sensor? Could my opti be bad again? Wiring harness to opti is good, power to coil from ignition is there, he started to mess around with wires near the coil and car started but we still can locate a faulty wire can someone please help.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Codes? Do you have manuals? Security light staying on? The Opti send 2 different signals to PCM. Supposedly PCM sets code if it gets one and not the other. If it recievers neither it wouldn't know engine is turning over; no codes spark. or pulse. There is a test or jumper harness to Opti if terminals are spread, corroded, or not fully seated could cause condition. Ground wires loose or corroded can cause all kinds of fun. I believe PCM grounds are on bell housing. Also make sure ground cable is clean and tight to block. There was a thread a while back about testing Opti with Ocyliscope. If wave form is correct to PCM it would eliminate opti and wiring from it.
