frankrizz

Hey Guys,
Was out with my rod the other day and encountered a weird
scenario. When my 4l60e tranny shifted from first to second gear I was taching at about 4500 rpm. My car started to stumble a bit then backfired.
I coasted to a stop and tried to re-start. I have yet to be able to start the car since. It will just crank. I have replaced my opti-spark and ignition control module about six months ago. Any suggestions where to begin?

Injuneer

Do you have spark on the coil wire, and at the plugs? Did you loc-tite the rotor screws when you installed the Opti? What brand is the Opti?

Scan it for codes. Check the fuel pressure.

Fatdog2

Isn't there a way to spray starting fluid into the motor and if it starts then shuts off,then it's the fuel pump.If it still doesn't start then it's electrical.Sorry,old school here.Hope this helps.

Injuneer

Got your e-mail response. Would prefer you reply in the thread, so others can participate in helping you.

We don't know if the Opti is the problem. Do the diagnostics first. And answer ALL the questions:

-did you loc-tite the rotor screws?

-do you have spark at the coil wire = Opti optical sensor working?

-do you have spark at the plugs = cap/rotor working (although not ruling out a loose rotor).

-did you scan it for codes? There are two codes for the optical sensor.

-what are results of fuel pressure check?

Here's another way to check the Opti:

4th Gen LT1 F-body Tech Articles

GaryDoug

Watch this video. The tachometer needle should rise to about 100-200 rpm while cranking. If it does not, it probably means the Optispark distributor or it's cable is not working.

frankrizz

Thanks, good info. Just discovered that my rotor screw came off and was
dancing around inside the opti-spark unit. Don't know if it did any other damage but just to be safe I ordered an AC delco unit from Summit and
I will definitely lock-tite the screw.