Ignition Riddle

[mhubbard]

The short version:
GW ran great most of last Saturday.... then later in the day seemed a bit tired and stumbly, so I drove it home for the night. By the next morning, I went to start it up and all she did was crank and crank but would never even come close to firing up.

Now for the backstory:
This car had been sitting for 8 months at a body shop. Earlier this month, I was able to drive the 15 miles or so from the body shop... got it home, but then she died on me on the way to dinner about an hour later. It turned out that the reason was the ignition coil (to distributor) wire was not making a good contact on the IC. Once I realized this simple fix, I snapped it on tight but also noticed that the top of the IC was leaking oil. Nonetheless, it ran just fine for much of the day after the wire was properly snapped onto the IC. As previously stated, it started to stumble later Sat afternoon and by Sunday wouldn't even fire up - not even pretend to. I went out and bought a new and correct IC, yet the problem persists. I tested the wire and it works fine (swapped it out to another similarly equipped car and it fired right up).

My friend thinks it is either the distributor (which was with the car when I bought it) or the Ignition module (which is maybe about a year old now). I know the modules are troublesome - and yes, I tried the hammer-method. If it is the dizzy, wouldn't it have given me some warnings of eminent failure? Or do they just conk out that fast?

Any suggestions would be greatly appreciated

Thanks,
Mike

[mhubbard]

Oh, and my truck is an 89 model.

[tedlovesjeeps71]

The module is a common issue but they usually just work or don't. Not usually a lot of warnings when they go. You could try a new one and see if it helps. They aren't expensive and good to keep a spare anyway.
You may want to get a multimeter out and check to verify that you're getting V to the coil and dizzy. And check that there is spark at the plug.

[REDONE]

I strongly suspect the ignition module. Have you checked for spark at all? Hooked up a timing light just to see if it flashes or pulled a plug wire while cranking to see if it'll shock the pee out of you?

Every duraspark module I've had go bad, did so intermittently. Absolutely drives me nuts. You fiddle with something else and it works again for a while, leading you to believe it's something else. After two or three bouts of the same symptoms and different things making it work again, it has always wound up being the Duraspark module.

[mhubbard]

Before I threw in the towel the other day, I did confirm that there is NO spark

[mhubbard]

My buddy (w/ electrical knowledge) who was with me that morning did some testing and tells me that I am getting current to the primary coil circuit... it turns on but does not turn off. but then the battery died after repeated cranking and we ceased further testing.

[tedlovesjeeps71]

New module time.
I know you said it wasn't that old but my experience is that is almost irrelevant. They are all hit or miss. Some last decades, some only days.

[fulsizjeep]

I strongly suspect the ignition module. Have you checked for spark at all? Hooked up a timing light just to see if it flashes or pulled a plug wire while cranking to see if it'll shock the pee out of you?

Every duraspark module I've had go bad, did so intermittently. Absolutely drives me nuts. You fiddle with something else and it works again for a while, leading you to believe it's something else. After two or three bouts of the same symptoms and different things making it work again, it has always wound up being the Duraspark module.

I have had them bite me hard enough to pee myself! Old School style. My experience with duraspark FSJs has been good. One failure where the goo started running out from under the module. It also gave me intermittent grief for a few weeks before it melted. My Duraspark experience is definitely better than my Prestolite experience. One time I saw Krista mad enough to burn it all to the ground after 4 module failures within a year.

[REDONE]

If you want to make sure the module is getting power in order to rule out a burnt wire or some secret unlabeled fuse, it's the connector that doesn't go to the dizzy. Red should be 12v in run, white or light blue should be hot in start, but may be 6 or 12 volts, don't remember 100%.

What your buddy was probably trying to say, is that the coil's circuit isn't getting interrupted (by the module). When the module breaks the coil's ground, the magnetic field collapses, which is what shoots all them volts out the big wire.

EDIT>> You darn skippy, Flint! I like Duraspark when it works. Most of the original modules lasted 30+ years to boot! I've found the Chinese replacements are just trash, after multiple tries I went MSD (and now TBI) and never looked back. There's a new(er) replacement that's made in Korea, but don't know how to verify it's the one in the rebrand box and can't say for certain it's better, only that it's supposedly a whole new design. This has lead me to believe it's really just stealth HEI off-the-shelf.

[tgreese]

... good to keep a spare anyway.

Indeed. Every Jeeper should carry a spare coil too. BTDT.

[tedlovesjeeps71]

... good to keep a spare anyway.

Indeed. Every Jeeper should carry a spare coil too. BTDT.

Or just delete it.

[mhubbard]

I just ordered the replacement ignition module from TGW... should be a few days before I can tell you more.

Thanks for the guidance!

[tedlovesjeeps71]

I just ordered the replacement ignition module from TGW... should be a few days before I can tell you more.

Thanks for the guidance!

Was it cheaper than rock Auto?

[mhubbard]

I just ordered the replacement ignition module from TGW... should be a few days before I can tell you more.

Thanks for the guidance!

Was it cheaper than rock Auto?

You know - I didn't even look. Probably not, but I prefer supporting a company that is dedicated to our crazy FSJ hobby. Besides, my boys had gotten me a TGW gift certificate for Fathers Day - so I basically paid for shipping only

[tedlovesjeeps71]

I just ordered the replacement ignition module from TGW... should be a few days before I can tell you more.

Thanks for the guidance!

Was it cheaper than rock Auto?

You know - I didn't even look. Probably not, but I prefer supporting a company that is dedicated to our crazy FSJ hobby. Besides, my boys had gotten me a TGW gift certificate for Fathers Day - so I basically paid for shipping only

That's good of you!

[ShagWagon]

You should order two of them and keep one on hand u till you pony up for a digital MSD 6al box.

[mhubbard]

Hey guys — yep, it was the ignition module. That last one ran for 4 months.

[REDONE]

I'm not surprised, it's a common theme here. Out of curiosity, did you see if the new replacement was made in China or Korea before you installed it?

[mhubbard]

I didn't see anything stamped or stuck to the module itself. It was boxed in crown automotive packaging... but I still have the box and will look closer when I get home.