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Discussion Starter #1
Howdy, folks. I'm hoping some one might be able to enlighten me on some issues I am having with my '89 E350 (school bus) with an E4OD tranny...

I parked the rig for a few days and my batteries died, and I mean really died (3.9 volts). I jumped the rig, drove a bit, and charged the batts. Using a multimeter I traced a power drain from the batteries to a wire that comes off the hot side of the starter solenoid. It was pulling 1.4 amps (when the bus is off). When disconnecting and reconnecting the wire I heard a clicking noise that I traced back to the transmission solenoid. With a friend tapping the wire, I pulled the solenoid connector off the transmission and immediately the clicking stopped. So I know that the power is coming to the solenoid from that wiring harness.

When I looked a the connector it was moist (seemed like water, not tranny fluid). I've cleaned the connector and where it plugs in. Still it is drawing power.

Next, I tried to start the bus. Glow plugs cycled, but nothing happened when I turned the key. I had to go under the rig and jump it with as pair of pliers. It ran fine, and I let it for half an hour, but there was flashing of the OD light (which means tranny problem).

I've never been about to pull codes from this baby. I've tried with and OBD tool and a multimeter. Just never had any signal come through.

I had a new starter relay on hand because I thought it was going out six months ago (bus wouldn't start, so I jumped it with pliers, but then never had an issue again). So I put it in today. Still wouldn't start with the key, and now the glow plugs don't even cycle. I switched back to the old relay and the glow plugs wouldn't cycle with that one now either. So I put the new one back in.

I can jump the starter either at the starter, or at the relay (by putting 12v to the ignition signal).

I tested the ignition signal at the starter relay and there is no signal when I try to start.

So, to sum it up: Tranny solenoid stays on, which drains battery... Now glow plugs wont cycle, and it wont turn over. No signal to the starter relay from the ignition.

Possible problems: EEC is acting up and telling the tranny solenoid to stay on. Ignition switch is out. Fusible link burt out (where? what does this look like?). Moisture on the tranny solenoid is crossing signals. What do y'all think?
 

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I think the EEC power relay is stuck on.
 

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Discussion Starter #4
Y'all are pretty smart. I tested the relay and there was low resistance (continuity) between the 12v in and the 12v out pole on the relay. I bought a new one, installed it, and now there is no clicking from the tranny solenoid when I disconnect and reconnect the 12v lead to the started solenoid. Job well done, however...

The glow plugs still don't cycle, it wont turn over when the key is turned to START, and now I'm realizing that my headlights don't work. I'm thinking it is a fusible link that might have been fried as I was working on all this (from jump starting, possible grounding, etc). Any opinions on this?

Where might the fusible links that I'm looking for be located? They are just sections of wire, right, that look burned when they are fried?

Thanks for the help guys.
 

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Discussion Starter #5
UPDATE: I went in search of fusible links, but instead found a wire that I had forgotten to hook back up to the positive side of the starter solenoid (Yup, that was dumb!). Once this was hooked back up my headlights and glow plugs are now working again.... HOWEVER, it still wont crank. I still don't think there is a signal getting to my starter solenoid (on the front fender, not on the starter). Any ideas? Ignition switch?
 

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Discussion Starter #6
UPDATE: After looking at what the possibilities were for no signal to the starter relay (MLPS, ignition, etc), I remembered that I had pulled the wiring to the MLPS (NSS) to see if the clicking in the tranny would stop. I went back under the bus to check the connection. I took it off, wiped it off and pushed it on real hard.

After that the bus started! I think I just hadn't put the wiring connector on hard/far enough.

I am back up and running!

Next project: 3G alternator swap...

Thanks people!
 

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if your having moisture issuse in the trans plugs you can get a tube of die-electric grease and put that in to help keep moisture out or see if your local parts store has the rubber seals for the plugs.
 

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For what it's worth, I've fixed a number of gas trucks with similar EEC relay problems. IE: phantom current draw, running poorly or not at all. On the gas burners the relay also provides juice to the injectors. The truck either runs so lean it backfires (injectors pulse but don't stay open long enough) or it won't run at all. I've found the EEC relay stuck with no deformity, melted engaged, and also with the power distribution center melted.

The root of the problem was excessive current draw (or dead short) at the solenoid pack in the transmission.

I wish you could have seen the look on a couple of the customer's faces when I told them it needed a part in the transmission to make it run.
 

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Discussion Starter #9
Devdg - forgive my ignorance. Is dielectric grease conductive? If it is, would you just put it around the side of the plug? If it isn't conductive, do you just smear a bunch in there? But wouldn't that potentially disrupt connections in the plug...

Fireman - What are you suggesting? Are you suggesting that my tranny solenoids are bad, or there might be a short in the solenoids, or perhaps it's the moisture in the plug causing a short?

Thanks, guys!
 

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typically it is non conductive and you only put enough on the end of the plug so that when it is plugged in it will squish around the pins and seal them to help keep the water out. I wash it out and reapply it every two years just to keep the water out, It also keeps oil out if you have oily plugs under the hood.
 
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