No Spark Troubleshooting Help

[Mmbackpacker]

I am working on getting my Cherokee up and running and have no spark...

Background, I have never seen this rig run, but it turned over and ran momentarily when I bought it- the gas tank was not installed, but with a little gas in the carb it would run.

I have the Sniper all T'd up, fuel supplied by a RobbMC surge tank. I am getting fuel to the Sniper, I flushed the system and the Sniper smells like gas. Further, it still doesn't start with starter fluid, so I am pretty sure it's a spark issue.

I have replaced the ignition module, coil (measures 0.00 ohms post to post and 8.66 ohms on the 20K scale post to tower), new spark plugs and spark plug wires. Stock Ford distributor but a new cap and rotor. I think I have all the wiring sorted out, with the excpetion of a white wire coming from the voltage regulator (?) box (silver box that for me is next to the ignition module).

Tried the method to check spark by taking the plug out and grounding the body and watching for a spark. No spark.

Any ideas on how to troubleshoot? What am I missing here? I do have an Ebay HEI distributor, but I think I came to the conclusion that I can't use it with the Sniper system.

[tgreese]

Which ignition system are you running? '75-77 Jeep used the Prestolite ignition, which is not Ford. In '78, they switched to the Motorcraft Duraspark ignition, which you could call Ford. It's the same design as a Ford ignition, but the distributor is made to fit the AMC block. Some parts interchange, some not.

You can see the coil spark by grounding and lifting the (-) primary wire and observing the spark from the secondary (coil wire) to the engine block.

A '77 360 uses the Motorcraft alternator with a mechanical regulator. It has no white wire that I can see. Look at figure 3-7 in the '77 TSM, free to read and download here - https://oljeep.com/edge_parts_man.html

Are you controlling the spark advance via the Sniper hardware? If not, the ignition should work on its own, with or without the EFI stuff.

Pictures of the components you are asking about will help.

[will e]

What voltage at the positive on the coil with the ignition in the on position?

[rocklaurence]

Id go back to a Carb to get this thing up and running. Once it runs then you can go to the EFI. Presently, you dont know if its EFI related or something else. I made this choice the other day when breaking in my crate motor. I did not what to ruin a new Rebuilt by trying to de-bug a Howell EFI. So, I rebuilt a 2150 carb, added HEI [already had one sitting in the shop], electric fuel pump connected to a 5 gal can and the motor fired on the first crank. I ran it for 35 minutes with good temperatures etc. Now I can go back and add the EFI.

[Renodemona]

So, is the sniper doing your ignition or just getting a signal from the stock ignition? If you are running stock ignition I would be suspicious of the module, the prestolite and motorcraft ones are kind of notorious for being dodgy even brand new (especially if chinesium). Have you checked timing, the cam gear, and the distributor gear? I would try getting it to run on a carb so you can sort those out before dropping on the Sniper. I'm not familiar enough with that system for any suggestions, beyond the generic checking proper phasing (if it uses it), 12v during run and start to the unit, relays actually closing the fuel pump circuit, fuel pump delivering appropriate pressure, etc. If you have wet (fuel) squish (timing) then you must not have bang (spark), or some combination of those. If you have the HEI distributor already, it is MUCH simpler for wiring, just needs 12V during run and start and you get rid of the 1970s ignition all together. Plus it throws 2-3 times more voltage which is nice. Good luck! Hopefully we were helpful!

[Mmbackpacker]

Thanks for the replies guys, I appreciate the time and thought. I’ll have some time to tinker tomorrow, I’ll let you know how it shakes out!