Which ignition module works best on a 4.2?

defmornahan

New member
I've had a problem ever since I bought this heep last year: It will occasionally die for no reason at all...at a stop sign, going 30 down the street, whenever. It's an every several days type of intermittent problem. It has never done it when the engine has been running more than 15 min, and it will usually happen multiple times in one day, then nothing for a few to several days. I've replaced the carb, Nuttered it, replaced the fuel pump, Team Rushed the ignition including replacing the coil. Oh, and took the head off and had it remachined. It does run much better than it did!...but it still did this random senseless dying crap. It also had something of a flat spot where it would not accelerate as fast around 1800-2000 rpms.

I had suspected the ignition coil before I Team Rushed the thing. When that didn't fix it, I began to suspect the module. I finally, last week, replaced the ignition module (it said Wells on the old module) with the $21 job from O'Reillys. Master Pro I think the new one's called. Ha ha. I haven't seen the intermittent dying problem again since, but it is early yet. Meanwhile, now the sucker has a flat spot down at maybe 1300-1500 rpms. If I'm coasting at 40 mph and then give the pedal a workmanlike shove, it will pause for a moment and then accelerate. And I just don't think the power is what it was with the old module.

Now, the power and the flat spot were worse before last night, when my buddy and I advanced the timing a little (from 8 deg BTDC to 10 deg) and rolled the fuel pressure regulator from 3.5 psi to 5.5 psi. The fuel tank or fuel lines back by the tank are dirty and the new fuel filter in front of the pump (that just got changed last week too) is getting dirty impressively fast. I also took the hard top off and put the old soft top on.

So with all that...is it the cheap ignition module that is my problem? If it is, what is the best reasonable (<$100) choice for a good module?
 

Try pulling & plugging the vacuum line to the EGR valve.

Mine had a weird flat spot, that was driving me nuts only in fourth gear above 50mph. It works fine now, so I just left it plugged!

Also your better off looking for a true Duraspark box at the junkyard, then that Wells junk.IMHO!

MSD might make a decent replacement.

Check this out, I think there are some others listed. This guy is TeamRush, he invented the mod!
Genuine Junk Yard Genius.com Ignition Upgrade, Jeep 258 CID I-6
 
Dying problem

FWIW, I've been driving it for a month and the random dying has not recurred. So if you have that problem and you have an old, cheap, or God forbid old and cheap, ignition module, maybe that's your issue!

PS MSD does NOT sell a module for < $100...they're a little out of my price range. The jeep with the new module has been working okay since I changed the fuel filter again and dropped the fuel tank and replaced the rubber lines back there.

I did plug my EGR valve, maybe that helped a little too.
 
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