I have a 93 firebird formula lt1. I changed the optispark, icm, and coil and still, no spark. Does anyone know what else i should check?
I just founf the issue my icm was a dudwhen you crank the engine, does the tachometer needle raise to a few hundred RPM? Have you tried flashing the codes? Are you sure the new ICM and Opti are actually good?
to check codes, open a paperclip and bend it into a U. locate the ALDL port under the knee pad to the right of the steering wheel. insert the paper clip into the two top right connections. turn key to RUN. Fans will come on, and the service engine/check engine light will blink. First code will always be 12. one flash, pause, two flashes. this means diagnostics are running. Note any codes. If you miss one, they will loop around untill key off. When done, key off, remove paperclip.
Load the main forum page (5 bars next to NEW at top right), locate the 4th generation topic and open it. Near the top you will find a pinned post for Factory Service Manuals. Follow the link in post #1 and get the FSM. You will need Adobe Reader to search through it. ...then when you're ready, buy an ALDL TO USB cable for OBD1 and grab Scan9495 from the ECU/PCM topic. That Windows program will scan for and clear codes, datalog, graph up to 4 sensor parameters in real-time, show ALL live sensor data, and actuate things like EGR, etc. ...or, buy a Chinese made Tech II clone which is the tool the dealer used.
sorry to say, but, of all the OptiSparks on the market, only reman-OEM and the custom built units from Petris Enterprises are reliable. Everything else regardless of brand or price is made of 100% Chineseium and are DOA or fail within 10,000 miles. Damn near everything on Amazon and eBay like the ICM is counterfeit Chinese garbage and also arrive DOA or fail very prematurely. ...so depending what you got, there's a good chance the new parts are bad.
when you replaced the coil and ICM, did you get all the ground straps back on and in the right location?