78 BJ40 won't run (1 Viewer)

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Hi folks,

This is my first post. I have been searching through the pages for several years but find myself in need of some help.

I have a 78BJ40 (24V) with B engine that I bought from Canada several years ago. Body and frame have quite a lot of cancer but it has always started and ran fine.

Last year she started cutting out on me. Would be driving along and then she would die or I would start it and she would die but in the end would run fine again. On our last trip, I had trouble getting it started after I stopped at a local store. On the way home she died.......and I haven't gotten it restarted.

I haven't done much trouble shooting but in searching the site I feel like it is related to the EDIC.

Here is what I know:
- It will run as long as it is in the start position
- When I release the key to the run position, it will die immediately
- I have observed the EDIC and it moves to the over injection position on start but when I release the key it goes to kill (I have video but don't know how to post it)

I'd like some advise on how to trouble shoot this and narrow it down.

Thanks,

Emilio
 
How is your oil pressure? I ask because the edic has a safety switch in the block beside your oil pressure sender. Without that signal the edic will shut the motor off. The oil pressure switch not to be confused with the oil pressure sender, wire is yellow/black.
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It can sometimes manifest as an anoying symptom of a much larger problem. Low oil pressure is not uncommon. In the past though I cleaned up all the contacts on the harness and it cleared up. Sometimes it's triggered with heavy electrical loads. I suspected bad grounds. Cleaning up ground straps connections is always a good idea. Redoing them is better. I'd do a lot of cleaning and testing before you switched out your control module or run it without the EDIC hooked up. This is a common problem that is widely covered. I do not like computers in old trucks. Did I mention that?
 
Thanks guys. I have suspected the switch. Is there a way to by-pass the switch to see if that may be the issue?
 
First you need to double check you have oil pressure. I can't stress that enough. Disregarding that can make an anoying problem into a gigantic one.

So pop this thing off of your EDIC motor by putting a flat screwdriver under each end and gently pry up. It's just a press fit. The fuel pump defaults to run when the arm is removed. To shut the engine off you need to push the lever the the pump side of the arm it's attached to. It's got a spring you need to over come and hold it for a few seconds till the engine dies from fuel starvation.
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That was a good test. I popped the arm off and she started and ran. The oil pressure on gauge barley climbed above the L mark. Was going to buy new sender and pressure switch as the next step? I didn't get a chance to clean up the grounds yet, ran out of day light.
 
it is common for the factory gauge to read low or just above low if you slowly rev the engine will the gauge climb to midway mark.
I would suspect your edic is your problem could be gummed up internally do a search there is a thread on cleaning.
 
The arm seems to travel fine between stop and over inject so has the full throw. It just doesn't stop on drive. I was going to chase the pressure switch unless you guys think this could be ground or gummed EDIC?
 
Following up on this. Turned out to be a stuck (welded) contact in the fuel controller. Contact was locked in the stop position so as soon as I let go of the key, would move the arm to the stop position.
 

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