84 grand wagoneer (wife's wagon)

I did this, I got a spark. Are you saying the pick up inside of the distributor is bad?

 

If I unplug the coil wire from the distributor and put a spark plug into it, then turn the key on for ~2 seconds then back off, when i turn the key off, i get a spark. to me, this means the coil is functioning as it should. Am I correct with that assumption?

With the 3 wire distributor plug unplugged, all 3 pins on that plug are grounded on the distributor side. on the wiring harness side, the top 2 pins give me 10.2v and 9.2v. I'm not sure what those are supposed to read, I will do some reading on that unless someone feels like chiming in here.

 

I used this method to test the pickup. It tested good. I decreased the air gap to .08 t make sure it was picking up good. I don't know what the spec is on it though. No dice there. I did notice that when the engine was in a certain position after attempting to start it, my dummy plug that was plugged into #8 on the distributor would spark with the 2 second key on test. I tried to pull the pick up off of the old distributor to test that on the new one, but its riveted and they aren't coming out without damaging the unit.

So, I hate firing up the parts cannon but i'm at a loss here. should I try a new pickup, or a new module?

 

well, I found a new in the box ignition module and threw it at it. no spark. I guess I'll be getting a pick up coil to throw at it. I'm not sure what else it would be after that. The only other clue I have to go on is the low voltage to the solenoid and + terminal.

 

It seems, two devices are hooked up in series. Otherwise, there's nothing running on six volts, in a vehicle using electronic ignition, except for a step-down resistor hooked up to the heater blower motor. I'd trace that wiring back and first look for visual signs of tampering. Often times, what seems to be a complex problem ends up linked to an elementary cause

 

So, Spec for coil + is 6v +/- .5v so I guess I'm in spec there. That would be that same as for the ignition terminal for the coil wire because they split off of the same wire at the ignition switch.

I finally cracked open the FSM I downloaded. I know, stupid me should have started with that, but it's not searchable and in a terrible format. Oh well. Stay tuned.

 

FSM says in step 1 if I'm getting 6v to the coil +, I need to replace the condenser mounted to the coil. The wiring diagram calls it a radio suppression capacitor. I didn't think those were necessary for the ignition system to function, and I am pretty sure it wasn't on there during disassembly.

For quick diagnosis, I'm going to attempt to use the capacitor out of my 70 country squire, unless someone suggests that that is a foolish idea.

 

No spark with the capacitor.

 

Maybe you need a wagoneer specific capacitor? The garage I worked at had two wagoneers come in. I didn’t work on either one but I remember a lot of profanity coming from that corner of the shop. Good luck

 

Those are only for ridding radio static. Therefore, even without it, the engine should run. The only reason it could stop your vehicle from running is if it's shorted out

A weak spark will look like a normal one, until having to spark under compression, because of the resistance caused by compressed air

 

Well, NAPA is going to give new a new pick up to try in exchange for the one that's in the distributor now. If that doesn't do it I will really be at a loss. I've passed all diagnostic tests and still nothing.

 

Well this is weird. I couldn't find my 1990 Chilton truck manual, until I realized, it's at the garage. I'm supposed to head up there in a while, so I'll grab it when I'm there, see if there's any Duraspark info on it for Jeeps.

 

That sounds like the case here, since all that's different is the distributor. Those electronic units will work for a long time. But, once they quit, you end up spending all that money you saved from not having to buy points and condensers. The last time that happened to me was on my Renault 5 (LeCar), as I was driving through northern France to get to the ferry sailing to Britain. As I got into the car, after having spent the night at a youth hostel, it wouldn't fire up. So, I went out and found a wreck that had a points distributor and then left it at that

 

I got spark! I switched the pick up coil with another and she's sparking. Now, It's still not starting. I can get it to fire up with my foot held to the floor, but it doesn't want to stay running. I'm going to double check that i'm not 180 out double check my plug wires, and then go from there.

 

Well, you're making progress, so that's good.