Glow Plug Controller

[Vindicator]

Hi all,
Havent been here in quite some time now...Beast broke down a few weeks ago. Goin up a main street and I lose all power. Whattya know it, she breaks down right in front of the local Autozone. I go in and my friend there gets me a Motorcraft CPS. I change it and go on my merry way. Not bad for an original CPS goin 116k. Anyways, truck has been running great as of yesterday. I'm having a starting issue and I believe the glow plug controller is the culprit. Here's what happens: I place the truck in the ON position and the dash lights all flicker erradically and then I can see that the batt. indicator slowly drops to the 8 volt mark. I then thought I could isolate the GPC by unhooking the 2 plugs that plug into the GPC. Again, I turn the truck in the ON position, but this time the lights do not flicker and the batt. indicator stays around the fully charged mark. Does anyone know how to test one of these boxes? I can see that there is a thick gauge wire that stems out of one of the plugs that plug into the GPC. Should there be voltage at that terminal at all times or? Any info is greatly appreciated all.

 

[Vindicator]

ttt Anyone?

 

[CHPMustang]

I don't have the experience to diagnose the GPC but I bet FordMasterTech,Ford_forgotton or one of the other gurus might be able to help.

 

[Vindicator]

Hey CHP!!! Hopefully, they'll chime in...Wouldnt this thing throw a code if its malfunctioning?! Weird!!!

 

[Doggy Daddy]

There are some codes that indicate Glow Plug system problems but I haven't experienced them. I'd suspect that if it did not work at all it might throw a code. That controller has one half and connector per bank and the gp wires are run to the controller individually (unlike Fed spec pickups that have a large wire per bank that splits inside the harness).

I think I'd Amp clamp the large power wires (blk/red, I think) one at a time and cycle the key. The gp's draw about 25 Amps each, so if either side draws significantly more (or less) than 100 Amps then trace the problem on that side. Give it a few minutes between testing each side for the gp's to return to cool temp for the most accurate reading. Could be as simple as a shorted gp or UVC harness.

 

[Vindicator]

Ahhh, I see DD!!! Well, the UVC harnesses are original, but I did replace the GPs around 65k. Would replacing the UVCs be a good preventative measure??? I know, I know..if it aint broke, why fix..but if I'm on a long road trip I dont wanna ruin it and be stranded just because...Where can I get my hands on an "amp clamp"? I have one of those analog load testers, but I'm unsure if it would work in this diagnostic application...

 

[Doggy Daddy]

The UVC harnesses are usually fairly durable on the '99 and up but there is a posibility that if a gp wire was in the wrong position that it could be rubbed by a pushrod or chafe itself against something.

The tool dealers have Amp clamps but usually not the best price. Seems to me that I have seen them in tool fliers from NAPA for about $130 (sorry) for a self-contained unit that also has multimeter functions (the Fluke I have is a separate unit that has to plug into a multimeter). If you do go in to ask about one it is probably called "Inductive Ammeter", clips around the wire being tested; in case the counterman does not recognise the term Amp clamp. It does turn out to be a handy tool but is a large bite to swallow if you won't be using it all the time. I'm not sure how your analog load tester is configured, possibly could be made to work with some experimentation

 

[Vindicator]

NEW INFO!!!

Thanks for the info DD. This morn, I load tested my batts and it seems that yet another Red Top Optima has bit the dust!!! I thought this problem was fixed, but yet again- it has resurfaced...This is horrible news for me lol It shows full charge, but when a load is placed on it, it shorts out. The batt. that has bit it was the pass. side one...What would cause a truck to eat batts? Faulty alt? I'm thinkin of switchin to some OEM Motorcrafts unless anyone else has a better suggestion???

 

[Doggy Daddy]

You know, I almost asked about your batteries; but you didn't mention any cranking problems.

It is my understanding that Optimas do not like charging voltage over 14 and I don;t think that the voltage is held at 14. I've known of a few Dodges that had this issue and their charging voltage is slightly higher than the Fords.

Motorcrafts are probably OK, Interstates have held up well. I hope that is all it is!

 

[Vindicator]

How good are the dealer Motorcraft warranties? Interstates? What is everyone running in their rigs??? I shoulda just replaced my oems with oems (sigh) We'll see how this goes!!!