1981 Wagoneer ignition problem. Help!

[Marwis]

I am new to the forum, but not to jeeps. I have a very nice CJ5 that I totally went through. I recently purchased a 1981 Wagoneer Limited for a new project. I have always wanted an FSJ. I felt she is worth saving despite the rust and condition. The Jeep SJ sat outside under trees for some time and was not running. I purchased the SJ for near nothing due to the condition and the fact that the owner lost all interest. I did all the normal things considering she had sat for a long time. Checked all fluids. Barred the engine over to make sure it was free. Put a little oil on top of the pistons. Drained old gasoline and put in fresh. Aired up what tires would hold air and luckily found a used replacement for the one that was totally rotted. Got a new fresh battery and installed. Cranked her over a few times and saw she was building oil pressure and the primed the carb and she started up!!!! Checked the transmission and she untracked and I drover her home which was about 6-miles.

The Wagoneer is a 1981 Limited. 83000 original miles. 360 cid 2-barrel. Automatic trans Quadratrac. The SJ is original except for larger tires and unmolested. I found that she has a battery drain so I installed a battery disconnect for the time being. Runs rough at present. Also has a brake issue and electrical issues such as windows not operating and a couple of gauges not working. All problems will be addressed in time and as time allows. I am a truck driver and on the road a lot.

Now for the problem. I drove the jeep a couple of times close to home. I put about 30 miles on her just to get a feel for issues. A couple of days ago I started her up, pulled down to my shop and left her at idle while I opened the hood and got some tools. She died. I figured she died due to rough idle and vacuum issues. She would not crank back up. I found she had no spark at the spark plugs. I checked and had correct voltage at the coil. Due to past experience I figured the ECM died and I went and got a new one at NAPA. Installed new ECM and nothing. Figured I got a bad one based, again on experience, so I went back to NAPA turned it in as bad and paid the difference and got the better Echlin ECM. Installed and nothing. Okay, time to check deeper. I found that the pickup coil in the distributor was dead; no resistance. New Echlin pickup coil installed and cranked her over and she started up. I let her run for a little while and turned her off in order to gather tools. within 10-minutes I went to start her up again and nothing! Cranks over but wont start (totally same problem). I again checked the pickup coil resistance and nothing. FSM calls for 400 to 800 Ohms. I did check the new one before I installed and it had 600 Ohms.

Okay, what killed the new pickup coil? I am at a loss. I plan when home again to check wiring between the ECM and pickup coil. Even that really doesn't seen very logical for the problem concerning she did run. The first pickup coil died when running, the second appears to have died when ignition was turned off. I now figure the ECM was never the problem and think maybe the original ECM was not bad, but that the original pickup coil merely died due to age. If that is the case, could the new Echlin ECM actually be bad and killed the second pickup coil? I am not aware of any other sort of issue that could the problem. I welcome all ideas and advise.

I am on the road right now, but appreciate any help.
Thanks, Mark

[Tatsadasayago]

The pickup coil is nothing more than a wire wrapped around an iron core, that when the reluctor passes by it induces a signal to the ECM to fire the coil.
I'd be looking at Previous Owner induced over/under voltages or a ground fault.

[Marwis]

Thanks Tatsadasayago,

I had wondered about a ground fault. I will check voltages also. I plan to also inspect wiring between ECM and the pickup coil. Will check voltage coming into ECM and ground as well as pickup coil ground. I appreciate your response.

Mark

[chevelleguy]

I had to replace my pickup coil several years ago and the new one crapped on me the next day, when it would get hot it would build up too much resistance. Once it died, I put my meter on it then blew compressed air on it and you could watch the reading come back into range. Warrantied it out and have never had another problem. Some times you just get a bad part. It was a BorgWarner Select, too.

[Marwis]

Thanks chevelleguy,
I got back home today. I checked and inspected the wiring. I checked voltage to ECM and was in spec. I decided I must have got new pickup coil that was defective. I returned it and replaced it. All is well now! Waggy starts and runs. Now to move on and take care of other issues. Thanks for the response!
Mark

[Tatsadasayago]

W00T!
Glad you got it sorted out mate!

[ShagWagon]

They should give you the part for free. Gotta hate that.

What a pain...

[Marwis]

NAPA did exchange the defective pickup coil. No charge.