GPCM
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Joined: Sep 2004
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From: Butler Pa.
GPCM
California vehicles operate identically to the 49-state systems. Instead of a 4-pole relay controlled by the PCM, the glow plug system contains an actual module. This module is in the same location but has more wires. The output terminal of the 49-state relay has one large wire for each bank that branches off to individual cylinders. The GPCM has one output wire for each cylinder. As with its 49-state cousin, it still contains the B+ wire, the vehicle power wire and the pink/orange to energize it. It also contains a communication line to the PCM. This module "monitors" individual glow plug draw and reports any errors to the PCM. It can flag a code P0670 if there is a control line fault, a P0683 if the diagnostic circuit is faulty and any combination of P0671 through P0678 for a glow plug fault in cylinders 1-8.
Since this module monitors actual current to each cylinder, the malfunction indicator light will illuminate and a code will be generated for any glow plug that draws less than 20 amps, even though no starting issues are present
As I read this if I have problems starting with the GPCM I will get a code if there is any problem with it. Never had any check engine light.
It will not start cold, it will fire and then quit. several times, if I stay on the starter it will run, but that can't be good for the starter.
Any suggestions ?
Thanks
armstrong
Since this module monitors actual current to each cylinder, the malfunction indicator light will illuminate and a code will be generated for any glow plug that draws less than 20 amps, even though no starting issues are present
As I read this if I have problems starting with the GPCM I will get a code if there is any problem with it. Never had any check engine light.
It will not start cold, it will fire and then quit. several times, if I stay on the starter it will run, but that can't be good for the starter.
Any suggestions ?
Thanks
armstrong
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Joined: Aug 2007
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From: Auburn, Wa
have you put a scanner on it? I know its suppose to bring up a light but if something odd has happened and it is not popping a check engine light you might not never know.
its the same set up on a 6.0 my buddies would not start either it turned out to be the GPCM.
its the same set up on a 6.0 my buddies would not start either it turned out to be the GPCM.
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Joined: Sep 2004
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From: Butler Pa.
I changed the GPCM, a new one from FORD, but when I start it the volt guage does not change, I realize it is op temp though. I have to leave it outside tonight to see if that CPCM will do the trick. I don't feel good about it. I may try to ohm the gp's tonight while it is in the garage. I am reading up on doing that right now, I just need to go down and find the valve cover plugs.
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From: Butler Pa.
I just remembered something I recently changed. I deleted the AIH to add my gauges. Could there be a wire I disconnected that also works with the GP's.
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From: Auburn, Wa
7.3L Wiring Schematic Printable, very handy. - Diesel Forum - TheDieselStop.com
here is a wiring Diagram I dont see the AIH going to anything other then the AIH from the relay. GPCM is on the third or so post.
I cant be sure on the gauges I dont know where you connected them.
here is a wiring Diagram I dont see the AIH going to anything other then the AIH from the relay. GPCM is on the third or so post.
I cant be sure on the gauges I dont know where you connected them.
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From: Auburn, Wa
following the path from the GPCM. It shows it getting its power from the starter relay through some Fuseable links it dont say where on the schematic. I would guess off hand it would be that box on the side next to the battery. Ill keep looking let me know if you get it going.
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From: Auburn, Wa
here is a TSB I also I found,
TSB 04-25-4
12/27/04
HARD START OR NO START - 7.3L
FORD:
2000-2003 E-Series, Excursion, F-Super Duty
ISSUE
Some 7.3L vehicles equipped with the glow plug control module (GPCM), may exhibit a hard start or no start condition. This may be due to the GPCM connector.
ACTION
A new GPCM connector service kit, available for the 6.0L engine, can now be adapted to the 7.3L engine. Refer to the following Service Procedure.
SERVICE PROCEDURE
1. Inspect the GPCM connector for pin conditions such as; pin fit, pull out, bent, corrosion, etc.
a. If a concern is found, replace the GPCM connector with the kit. The kit contains a replacement connector with pigtail to be spliced into the existing harness.DISREGARD THE INSTRUCTIONS INCLUDED IN THE KIT (WHICH ONLY APPLY TO 6.0L) (see this image)
b. If no concerns are present, proceed with normal diagnosis.
GPCM Connector Kit - Part number 4C3Z-12B568-AA
TSB 04-25-4
12/27/04
HARD START OR NO START - 7.3L
FORD:
2000-2003 E-Series, Excursion, F-Super Duty
ISSUE
Some 7.3L vehicles equipped with the glow plug control module (GPCM), may exhibit a hard start or no start condition. This may be due to the GPCM connector.
ACTION
A new GPCM connector service kit, available for the 6.0L engine, can now be adapted to the 7.3L engine. Refer to the following Service Procedure.
SERVICE PROCEDURE
1. Inspect the GPCM connector for pin conditions such as; pin fit, pull out, bent, corrosion, etc.
a. If a concern is found, replace the GPCM connector with the kit. The kit contains a replacement connector with pigtail to be spliced into the existing harness.DISREGARD THE INSTRUCTIONS INCLUDED IN THE KIT (WHICH ONLY APPLY TO 6.0L) (see this image)
b. If no concerns are present, proceed with normal diagnosis.
GPCM Connector Kit - Part number 4C3Z-12B568-AA
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Joined: Sep 2004
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From: Butler Pa.
I plugged it in and it started . I will check tonight by leaving it outside again . I always had dim headlights on my 97 for about 45seconds after it started so I knew they were working.
Thanks for your help.
Thanks for your help.
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Joined: Sep 2004
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From: Butler Pa.
We will see first thing tomorrow morning after it sits outside all night. I also found my steering problem with new tires. Had BFG AT's could not turn wheel sitting still, was having to straighten the wheel after turning at an intersection, new tires and problem gone.