Expert: Kevin Pilotte - 12/11/2009

Question
QUESTION: hi, I just bought a 76 cj5 with 304 and a howell tbi kit installed by previous owner.
my question is, runs rough, passenger side exhaust sounds strange to me, like an erratic "pop" and the distributor Cap shows wear on the very edge of the electrodes, seems like the distributor timing is off to me, but need your opinion, should I replace the timing set, or just try pulling and reinstalling the distributor ? Also do I need the ballast resistor on the motorcraft ignition setup? Because its there but not hooked to anything. Thank you for your time.  p.s  called howell but they aren't any use for anything at all I also have the service manual

ANSWER: Check the firing order. It should be 1-8-4-3-6-5-7-2
Also, the engine can pop like you describe if a rocker arm support is broken, which is not uncommon on this engine.
Make sure all cylinders are firing.
The Motorcraft ignition came with a resistant wire from the factory, the wire running to the (+) side of the ignition coil.
I don't know what you mean by replacing the timing set. What parts are you referring to?

---------- FOLLOW-UP ----------

QUESTION: Thanks for your reply, I checked under valvecover, I see nothing broken. I reset distributor to no avail. By timing set I meant chain and sprockets under timing chain cover to make sure cam hasn't jumped. Plugged egr port. Plugged intake vacuum ports. And no resistor on coil. Thanks  

Answer
You can inspect the timing gear & chain, but it would require a bit of work to access it. The original timing gear had nylon teeth and over time, the teeth on the gear could break.
Something you can do that might be easier:
Remove the valve cover so you can see #1 cylinder valve train. Using a dial indicator, rotate #1 cylinder until both valves are closed and the #1 cylinder camshaft lobes are at their lowest point;
the timing mark on the timing cover should be at TDC or 0. If its not, your valve timing is off.
You also might want to do a compression test or cylinder leakage test.