Strange issue - starting and GPR related

maxtrax · Jul 30, 2013

So I am trying to help a friend fix his truck (early 99 7.3 PSD). It wouldn't start when the temps are 40 or less without the block heater. I checked the GPR and it turned up bad... it would click as if working properly but pass no current through it (constant 12V across the big lugs). Glow plugs themselves checked ok.

I picked up a new GPR from the International store and put it in. Seemed to work ok and the truck started right up. Couple days later the truck was moved around and hooked up to a trailer. Total run time was a couple minutes with the new GPR. He told me it quit, and would only run for about 5 seconds when trying to restart it. I took my truck and we jump started it and no matter what it would only run for 5 seconds.

I disconnected one of the small wires from the GPR and it will start/run just fine. It was clicking like normal when i installed the GPR but now does not click when you turn the key. It will click and pass current with the small wires disconnected and manually jumping power to the small pins.

Hooked my auto-enginuity up to it and pulled these powertrain codes:
P0380 Glow plug/heater circuit A
P1316 Injector Driver Module Codes Detected
P0344 Camshaft Position Sensor A circuit intermittent (bank 1 or single sensor)
P0470 Exhaust Backpressure Sensor

KOEO (key on engine off) with the GPR hooked up resulted in:
P0380 Glow plug/heater circuit A
P0470 Exhaust Backpressure Sensor
P1219 CID Low

KOER (key on engine running) with GPR hooked up resulted in:
P1219 CID Low

Buzz test would not complete with GPR hooked up.
Cylinder contribution without GPR checked out with just the normal cylinder 8 failure.

Small wires are red and orange (or light red). Both wires were returned to their respective places that they were on the original GPR.

Arisley · Jul 31, 2013

Sounds like you have another bad GPR. That's where I would start anyway. Then clear the codes and start over. See if you can get those IDM codes first.

maxtrax · Jul 31, 2013

You cannot hook the two small wires up wrong on the GPR if one goes to each post correct? There were no instructions in the package and I figured they would both be isolated from ground.

Other codes that came up were in the "GEM/Central Timer" section:
B1352 Ignition Key-In Circuit Failure
B1318 Battery Voltage Low - Most likely from draining it from him cranking too long
P0500 Vehicle Speed Sensor A

I don't know how long it has been since any codes have been pulled from this truck previously.

When doing the KOER Glow Plug test it came up P1219 CID Low

POWER-STRUCK · Jul 31, 2013

of the small wires one is an exciter and the other is feedback to the pcm. it is possible to get them switched, but more likely a bad relay if it worked a few times. most of these components are now made in mexico or china and the quality control has suffered.
don't rule out the possibility of bad injectors also causing a harder than normal cold start. and remember that if the relay was dead for a while the glow plugs can now fail after a new relay since they can now pull a load!

pretty simple to test, apply power to the large stud and gound to the base. then apply power to each of the small posts and when you get the correct one the other large stud will then have power

neverkickn · Jul 31, 2013

The truck is firing and running for a few seconds before shutting off. Is it possible for a bad gpr to kill the motor. Is this a GPM (cali truck) or a gpr? Does it run smooth when it starts up, or does it sound like an old tractor? I would run a buzz test and go from there. If you have a bank down due to an idm failure it can start up and run for a few then drop out like that.

maxtrax · Jul 31, 2013

It is a gpr not a module. The truck runs fine when the gpr is not wired in so I know it's not the injectors. When it starts up with or without the gpr plugged in it works fine. However, when the gpr is hooked up it acts like the fuel pump isn't working and just won't fire. When it does hire it runs fine but dies after 5 seconds. When it does it just shuts off like the ignition was turned off... No romp or stutter.

Buzz test would not finish even after about 10 minutes with the gpr plugged in. It will buzz all the cylinders and the do about three individual and seems to get lost.

maxtrax · Jul 31, 2013

POWER-STRUCK said:
of the small wires one is an exciter and the other is feedback to the pcm. it is possible to get them switched, but more likely a bad relay if it worked a few times. most of these components are now made in mexico or china and the quality control has suffered.
don't rule out the possibility of bad injectors also causing a harder than normal cold start. and remember that if the relay was dead for a while the glow plugs can now fail after a new relay since they can now pull a load!

pretty simple to test, apply power to the large stud and gound to the base. then apply power to each of the small posts and when you get the correct one the other large stud will then have power

Because the truck starts fine with the gpr unhooked (it's still warm out) I don't think the gpr or glow plugs are the issue. I also disconnected the two smell wired and jumped power to the gpr and it does click on.