GP Operation Issue (1988 7.3)

[HammerDown]

Owned my 1988 F250 7.3 since new.
Over the decades I've diagnosed and repaired the usual 'rapid clicking' issue from a bad GP or a few.
Last year I diagnosed and replaced the faulty GP Controller with another GP Controller unit from Ford.
Now what's happening...
#1 sometimes getting the rapid short GP clicking/cycling.
#2 sometimes no WTS light or GP burn at all.
#3 sometimes it works as should.
I just went through all steps on the GP diagnoses and everything checked to be ok.
#4 can the GP Controller intermediary act up before it fully fails?
* the current installed Ford GP Controller has another two year warranty... I can get another free. But again, every test in the book was a 'pass'.

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[HammerDown]

So no one has had a GP Controller act-up to maybe what I'm experiencing?
BTW... my local Ford stealer where I purchased the prior GP Controller (1.5 years ago) is trying to screw me out of the three year warranty.

 

[Cubey]

Perhaps the solenoid is bad?

 

[franklin2]

I had the same intermittent problem. I found after I messed with the wiring plugs on the glowplugs themselves, it would start working again for about 2-3 weeks, then it would mess up again. I would go out and unplug and plug back in all the plugs on top of each glowplug, and again it would straighten out for a couple weeks. My problem ended up being bad connections at the glowplug tips. I replaced the connectors on the glowplugs and the problem did go away.

 

[Nero]

I also had a similar issue, but found it was where the main hot wires came in to the engine harness, had melted the connector. As soon as I bypassed it, worked fine.
Check for battery voltage at the yellow wire at your GPC.

 

[HammerDown]

Perhaps the solenoid is bad?

On the passenger side fender well???

 

[HammerDown]

I also had a similar issue, but found it was where the main hot wires came in to the engine harness, had melted the connector. As soon as I bypassed it, worked fine.
Check for battery voltage at the yellow wire at your GPC.

I did have corrosion at that connection (multi pin plug) with the two heavy yellow wires. Cleaned all that up and made a better connection and all was good for over a year and a half.
But again, just the other day I performed all the steps to test the GP and Controller and everything passed.

 

[HammerDown]

I had the same intermittent problem. I found after I messed with the wiring plugs on the glowplugs themselves, it would start working again for about 2-3 weeks, then it would mess up again. I would go out and unplug and plug back in all the plugs on top of each glowplug, and again it would straighten out for a couple weeks. My problem ended up being bad connections at the glowplug tips. I replaced the connectors on the glowplugs and the problem did go away.

Just curious 'if' you performed the test for the GP female ends as I did?
I can absolutely agree that resistance can build up in those little push-on plugs. I've always put a little dielectric grease in them to help make a better connection.
Question... what plug-ends did you put on the wire ends?
A few of those wires especially on the passenger side are very short and under the hard injection lines.

 

[Cubey]

On the passenger side fender well???

The one bolted on top of the controller

 

[franklin2]

I used the female part of this type of connector and crimped it on the glowplug wire.

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Full disclosure: After awhile I went to manual glowplugs. I then did not care if one or two wiring connections were iffy, the engine always starts with the manual button.

 

[MtnHaul]

The factory setup is great when everything is perfect and it will let you know when something is wrong by giving you a short glow and lotsa' clicking. But with a manual GP even if 2 or 3 plugs are burnt out or wiring is bad you can still get a good glow on whatever plugs do work and at least still start your engine. 35 year old wiring can be a source of unneeded headaches and it's not that hard to make a new harness and go manual. When I convert my 1990 to manual I plan to just mount a solenoid and switch the ground on/off to activate the plugs.

 

[franklin2]

The factory setup is great when everything is perfect and it will let you know when something is wrong by giving you a short glow and lotsa' clicking. But with a manual GP even if 2 or 3 plugs are burnt out or wiring is bad you can still get a good glow on whatever plugs do work and at least still start your engine. 35 year old wiring can be a source of unneeded headaches and it's not that hard to make a new harness and go manual. When I convert my 1990 to manual I plan to just mount a solenoid and switch the ground on/off to activate the plugs.

It's too easy to just use the solenoid already mounted on the factory controller. Cut the white wire and ground it with a momentary switch inside the cab, done. The white wire is what the "brain" uses to ground the solenoid to activate it. By disconnecting the white wire and hooking it to the switch, you are taking control away from the controller brain.