I like it hot but not that hot! (GPR Issue)

[jakescars]

I know that there is alot of talk of gpr issues and hard starts on here, however I can't seem to find mine. My 01 f350 has had a bad current draw to the point of dropping down to around 9 volts while driving at 1800 rpms (dvm wired direct to charging post of alternator so I can monitor while driving). The gpr has 12 volts constant to input side and zero to the output with key off. Once key on output also has 12 volts as well does the s terminal(closest to front of truck). After about 15 -20 minutes of warm up and even a short drive the gpr still has 12 volts on both main big lugs and they are hotter than #^#*. I did read that after warm up that you should have 12 v on the input and 12 v on both small posts, I have 12 v on input, output, and the frnt small terminal and only 6.85 v on the other small terminal(" I "terminal I believe). What is telling this relay to stay open constantly. BTW this is the second relay I have tried in 2 weeks so I am pretty certain it has nothing to do with the problem.

[megawatt00]

The GPR get it's signal from the PCM. FOr some reason the PCM is telling it to stay on. I'm not to sure if an AE will scan for issues like that though. A quick and simple fix is to put a switch in line and manually control the GPR. The added "run time" I would imagine is decreasing the life expectancy of the GP's as well.

[jakescars]

Thanks Jim I just used my Hypertech tuner to check for Dtc's and came up with P0380 which tells me nothing other than a gp ciruit fault.

[megawatt00]

Originally Posted by jakescars

Thanks Jim I just used my Hypertech tuner to check for Dtc's and came up with P0380 which tells me nothing other than a gp ciruit fault.

The Ford Code says fault on Ckt A
P0380 Glow Plug Circuit Error Circuit A

That may be GPM specific though. Maybe someone with an AE will chime in. I just got one and haven't started to "play" with it yet.

[Izzy351]

I would disconnect the GPR (small control lines) and tape up the wiring until you can figure it out. You don't want them running all the time. That's very strange and I'm curious what the issue will end up being. It could be as simple as the PCM not sensing that it's on. Check the wiring really well to make sure it's where it's supposed to be and not broken or shorting out.

[jakescars]

Izzy351 are you talking the two small terminal wires on the gpr? This is my everyday driver and I live where the snow flies, this will make it difficult to start the truck correct? Would I still be able to jump the relay with a screwdriver with these disconnected?

Thanks for you all's help
Don

[tdpower]

Are you sure that you have a glow plug relay and not a gpcm? There is also a AIH relay in front of the glow plug relay. Just making sure you are not measuring the AIH relay. That would make more sense for that one to stay on longer when cold. You might consider a switch like Jim mentioned. I would use a push button one so it would not stay activated accidentally. The pcm sends a ground to the GPR to activate it. So if you did that you would want to disconnect the wire from the pcm to gpr and wire from ground to the switch and then to the gpr. I'm not sure which little post it is but here is a wiring diagram: http://www.thedieselstop.com/faq/949...Econoline1.pdf

A lot of people do an AIH delete: http://www.dieselsite.com/index.asp?...PROD&ProdID=48

[parkland]

I wonder if its an Air intake heater problem?

[hucka1a]

I would do like Jim suggested and run it through a switch until you can track down the culprit.

[danskool]

I wonder if the relay just sticks. From all the arching and the spring isn't enough force to unstuck it.. They get pretty burnt on the inside of the factory relay and the contacts could fuse. I put in three Napa relays (Them relays are junk)in one summer before i found out about the stancor. . You also might want to ohmm out your GP's encase one or a couple are shorted.

[jakescars]

It is a gpr and not a gpcm. I thought about disconnecting the gpr and using the AIH relay in its place just to check.

Just a bit more info: when the original OEM relay bit the dust a year ago I grabbed one from Checkers ($60) and it worked fine all this time then about 2 weeks ago I had a hard start and decided to try jumping the relay and the truck fired right up, I went and got checkers to warranty the relay so I put in the new one and all this began. Last nite I took that
relay and went and warrantied it also and the same problem, this is why I don't believe it to be the relay or could it.

The guys at checkers told me that they just started getting these from a different company and they are suppose to be better but I am begining to wonder.

Thanks guys!

[jakescars]

One more question. If the pcm is controlling when the relay should work or not what determines that. Hope that makes sense

[PaysonPSD]

Originally Posted by jakescars

One more question. If the pcm is controlling when the relay should work or not what determines that. Hope that makes sense

Engine oil temp will determine how long the GPR stays operated. You may just have a bad EOT sensor. The proper scanner, like AE, can monitor oil temp.

[jakescars]

just an update! Well we got the whole system scanned and tested and found nothing other than code P0380 again. The problem seems to have changed a bit in that sometimes now we cannot get the circuit to complete to fire the glowplugs but if we ground the pcm post on the gpr then they will fire and stay constant untill we shut the truck off. I am going to test to make sure that I have no issues between the pcm post of the relay and the 101 pin on the pcm harness.

In the event that the harness is good to go I seems that I am looking at a new pcm, whats everyone think?

Thanks
Don

[megawatt00]

That what it seems like to me Don. The output on the PCM is erratic.