93 4.3 chevy truck no spark.

[Bob252]

changed cap,rotor,control mod,both ignition switches and coil nothing has worked. crank no start. please help.

[Palf70Step]

I wish I could remember which one, but I had a fuse blow and it killed everything, including the diagnostic port. It would crank and crank and never go.

[Kudzupatch]

I assume you mean you put in an ignition module?

Then next step as said, it make sure you have 12 volts to the module and if not work backwards.

[Richard2112]

crankshaft position sensor

[sntrym95]

Originally Posted by Richard2112

crankshaft position sensor

The 1993 4.3 used a TBI injection system which does not have a crank sensor. The distributor is used as the rotation sensor and gives a reference pulse to the computer which tells it to fuel and fire.

Check the distributor module per some other posts on here. I should also note that not all modules are created equal and the new one may not be good. Check it to make sure. Also check for voltage along the way.

You didn't mention if the injectors were firing. are they?

[Bob252]

Originally Posted by Palf70Step

I wish I could remember which one, but I had a fuse blow and it killed everything, including the diagnostic port. It would crank and crank and never go.

yes I checked the Crank fuse.. Its okay!

[ChevyTech]

Did you make sure you have power to the Ignition coil when the key is in the on position?

Test the pickup coil in the distributor.

Pickup coil testing:

500 to 1500 ohms between terminals.

Infinite from one terminal to ground.

When testing the pick-up coil resistance, the key should be off, and the pickup coil should be unplugged from the distributor module.


Another possibility is the magnetic material on the reluctor on the distributor shaft that spins in the pick-up coil has cracked making a less powerful magnetic field for the pick-up coil to make a good pulse signal.