I have an 84 S-10 Blazer, carburated 2.8 v6 all stock, motor starts and runs fine then dies after 5-10 minutes. Fuel is all good, but it looses spark. I had the ignition module tested six times in a row to heat it up good, it was fine. all plugs, wires, cap, and rotor. Any Ideas? Thanks

 

might want to look into EGR function there. It may be sticking open too far once you are warmed up.

 

I really do not believe it to be the EGR as the only thing it lacks to run is spark, which comes back after it sits half an hour or so, unless I'm missing somthing

 

Did you test the coil itself as well?

 

no, I am unsure how to test the pick up coil with distributor still in truck, any help would be appreciated. However I was under the impression that they were either run/no run do they act up like the modules?

or did you mean the ign. coil? If so no I have not, unsure of resistances for this truck.

 

I did mean the ignition coil. Is your distributor the typical HEI style with the coil mounted in the cap? or do you have the HEI-EST setup? When you mentioned the control module, I am unsure if you were talking about the one mounted in the base of the distributor or not.

Some people have had somewhat intermittent problems with the pickup coil as well that have been traced to a cracked pickup coil.

 

no it is the newer separate coil but still has small 4 pin module

 

Ok. That's the HEI-EST distributor. To test the coil, first test between the battery and tach terminals; the resistance should be zero or nearly zero. Then test between the batt terminal and the ground screw (one of the retaining screws) and the resistance should be infinite (open). Those are the two primary resistance checks. For the secondary resistance, test between the tach terminal and the secondary output (terminal where the coil wire to the distributor connects); the reading should be less than infinite (between 6000 & 30000 ohms). If any one of these readings is out of spec, replace the coil.

To test the pickup coil, disconnect the coil leads from the HEI-EST module N & P terminals (usually the green and white wires). From either pickup coil wire, test the resistance to the distributor base. It should be infinite (open). Next, test the resistance between the two pickup coil wires. The resistance should be a consistent reading somewhere between 500 and 1500 ohms. If either is out of spec, replace the pickup coil.

Both tests should be done both in the cooled down state and at full operating temperature if possible.