Replaced distributor, no spark now.
 

Distributor failed. Pulling into a parking spot and a snap noise from under the hood.



Engine at zero rpm. No restart. Was below 0 deg F that day.



Bunch of monkey biz later discovered the dist cap loose, and the front screw snapped the base plate hole off and the rear screw popped its head off. (while shopping for a distributor I notice they make a repair part for this.... costs about as much as a new distributor – typical GM quality job none I guess)



No clue which was first, but the cap was unattached. Must have been the noise I heard.



Had it towed home and bought a new distributor.



Install went fine. Lined up perfect.



But no spark now.



No spark using a plug off the coil wire.



I swapped over to a spare known to be good coil and still no spark. Ditto with ICM.




What might have been fried when the distributor cap popped? The new distributor feels rock solid and spins with the engine cranking. Oil pressure jumps right up when cranking. Tach needle does not move ( I think) .



So which one of you recognizes what the problem is and can save me a ton more trouble shooting??



Also, plenty of fuel at the Schroeder valve while cranking, no help from putting anything down the throttle body.

ps nice to meet you all. - just joined up to get some help. thanks!

What year is it? On the newer ones, the crank sensor is what tells the PCM to fire the coil. You would get spark at the coil, even if the distributor wasn't plugged in.

With the cap off, does the rotor turn when you crank the engine?

Thanks Tom. 1998. I will remove, clean and inspect CPS today. I just can't figure why it would magically fail at this time.

I did check for the rotor spinning, and it does.

thank you

Sure doesn't make much sense. You checked the fuses, right?

So many times.

I read the Haynes manual and the sticky here and a bunch of threads. Heading out right not to check all the grounds and that sensor and some other things on my list

No luck. Pulled and cleaned the CPS , looked OK but who knows. Went thru a bunch of other stuff but no spark.

I ordered a manifold pressure sensor (because last year I got restarted by cleaning that) and a CPS .

I'll try them when they arrive.

Until then unless someone sells me a clue I am just going to wait.

Do you have a scanner? Can you check for a tach signal (RPM reading) while you're cranking it?

I have a cheapie OBDII scanner which shows no codes.

I doubt it can check the tach signal.

Is that generated by the CPS?

The tach needle does not move while cranking..

It seems like the tach needle should move a little while cranking. Maybe somebody who's near their Blazer can confirm? At least on my 2000, the ngine will run, even iff the distributor is unplugged. The crank position sensor is what "tells" the PCM to fire.

If you have a test light, maybe check for voltage at the positive coil terminal. It should have 12V. and if you put a test light on the negative coil terminal, it should flash on and off while cranking.

Thank again. My new CPS should be here soon. I'll swap that before I play any harder. <$10, if it not the answer the old one will be a spare. If it fixes things the old one goes in the trash. Ditto with the MPS.

I'll let you know next week :D