V6 Running Poor Suddenly. Loosing Spark When Accelerating

Jeep sat for the past week. I changed the water pump yesterday, Because of a very small leak. Im pretty sure that has nothing to do with the problem.

Test drive went very poorly. Backfired lots and stalled several times. (Pump didn’t leak). Barely made it home.

Back home
I checked all the wires and all looks fine. Cooled off just a little and Restarted and idle seems ok. Put the timing light on and confirm timing is correct. Tried to increase RPM and timing light goes dark and engine stalls or dark and comes back when I pump pedal or come back to idle.

It has a CRT brand HEI
Coil? Or ICU? Or ???

 

if spark is completely disappearing, it's either going somewhere else or not being created at all. the fact that it shows up at low rpm makes me think it's not going somewhere else, rather being cut off completely. seeing as it happens when you rev it up, I'd think it would be something advance related. I don't know how the distributor you're using is set up, but if it runs the stock HEI type advance, the entire pick up coil assembly moves when the vac advance moves - potentially causing interference between the wires for the coil and other parts in the distributor, especially if it's a distributor that's been made specifically to be smaller than a standard HEI. i'd say pop the cap at the very least, and check anything advance related.

 

I Sent the testing procedure for the thing inside the Whatchamacallit. I agree it's electronic or vacuum related. Does the pcm have any feedback? Any rpm blips?

 

If you have a points system, check they are cleaned and the gap is adjusted to spec. If incorrect the symptoms you describe may occur. If the points are 'burnt' you may find the condenser has failed.

 

Fixed it.
I was pulling apart the distributor to test the coil and found some water under the coil area. Quick blast of air and let it sit open while I tested the coil. Now everything is just exactly perfect.

Thanks all for the input.

 

Sooooo.......how'd the water get in there? You may need to seal up that distributor somewhere or maybe a poorly fitting cap. Glad it was a simple fix.

 

It might have been the pressure washer after the last wheeling trip.