Ford Truck Enthusiasts Forums - Truck won’t shut off

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Truck won’t shut off

So I get a call last night from a buddy with his E99 that he has the ignition turned off and key out and it won’t shut off. Batteries are disconnected and it is still running. I told him to pull the 30amp fuse for the fuel bowl heater & pcm. No go. Still running. I forget what his son did but eventually he got it to shut off.
But as soon as he connects a battery, everything turns on like KOEO.
I am thinking the rod along the top of the steering column or the switch it activates but someone told him to start the truck, disconnect the batteries then disconnect the alternator. If it dies it is the alternator. HUH? No batteries, no power from alternator... of course it will die... right?

Thoughts?

Thnaks all!

Shorted internal components inside the GPR, common on 94 - 97 OBS rigs so believe it's the same issue on the E99. When this happens the key ON small wire to the GPR and the large power ON always wire will back feed past the ignition switch to the PCM and fues 30 keeping the engine running. Of course disconnecting both batteries would kill the operation, which I guess was the solution? Just replace the GPR and the problem will go away. I have some pictures on a dissembled GPR and it becomes clear why this can occur, if interested.

Is there any type of monitor hooked up? Possibly a turbo cool down timer??

Though it is a Diesel, it does require certain electrical components to be operational to operate as designed. If it is deprived of 12v, it can't run for long - unless it's munching engine oil through the turbo bearings... NOT as designed. But that isn't usually described as a "won't shut off" condition.

Quote:

Originally Posted by Hussler (Post 18414192)

I totally missed that and it makes complete sense. (Engineer by trade.). Once you explained it the hamster 🐹 in my head turned on the light. Thank you! I called my buddy and he replaced his GPR about 4yrs ago but with a POS from Autozone. Over $100. So I just sent him the info on the stancor. I have had mine in for almost 9 yrs now with no issues.

Quote:

Originally Posted by schlepprock250 (Post 18414325)

Is there any type of monitor hooked up? Possibly a turbo cool down timer??

nope... nothing additional hooked up. Gonna replace the GPR and go from there.

Thnaks for the info!!!!!

OK Change up. He said he replaced the GPR awhile back...But it was the GPCM. He has a Cali truck. Build date 8/98

Any other thoughts or continue on the route of replacing the module? And it is an E99.
No remote starter or alarm.

Billy, how do the two differ in functionality? Any chance he has a spare to swap out?

Billy,
I found the following . It looks like the Cali GPCM, will set a code if it fails....

The engine uses a glow plug system that preheats air in the combustion chamber to improve cold engine starting.
The system consists of:
^ intake manifold glow plugs.
^ glow plug relay.
^ Powertrain Control Module (PCM).
^ Engine Oil Temperature (EOT) sensor.
^ Barometric pressure sensor (BARO sensor).
The glow plug system is electronically controlled by the powertrain control module. If the temperature is below 55°C (131°F) the powertrain control
module will energize the glow plugs immediately after the key is placed in the ON position. Then, depending on the readings from the engine oil
temperature (EOT) sensor and the barometric pressure (BARO) sensor, the powertrain control module determines how long the glow plugs will be on.
Glow Plugs - PCM-Controlled
The intake manifold glow plugs are located in the cylinder heads, under the valve covers.
The glow plugs are self-regulating. If the engine oil temperature is above 55°C (131 °F), the powertrain control module will bulb-check the WAIT
TO START lamp but not energize the glow plug relay.
The powertrain control module protects the glow plugs by energizing them for short durations if the battery voltage is abnormally high.
The glow plug ON time varies from 0-120 seconds depending on battery voltage, engine oil temperature and barometric pressure.
On California vehicles the glow plug monitor system is part of the On-Board Diagnostics II (OBD II) System.
The Glow Plug Monitor (GPM) system is designed to find failed glow plugs or failed wiring in the glow plug system.

The GPM system uses a low resistance shunt to conduct current to the left and right bank glow plugs.
Three sensing wires measure the voltage drops across the shunt when the glow plugs are operating. A failure in the glow plug system will set a
Diagnostic Trouble Code (DTC).

Glow Plug Relay Control - Federal
The Glow Plug (GP) Relay Control is used to energize the glow plugs for assisting cold engine start-up. Engine Oil Temperature, battery positive
voltage (B+), and Barometric Pressure (BARO) are used by the PCM to calculate glow plug on-time and the length of the duty cycle. On-time
normally varies between 1 and 120 seconds. With colder oil temperatures and lower barometric pressures, the plugs are on longer. If battery voltage
is abnormally high, the duty cycle is shortened to extend plug life. (The glow plug relay will only cycle on and off repeatedly when there is a system
high voltage condition greater than 16 volts.)
An open in the glow plug relay circuit will render the glow plugs inoperative. A short circuit will result in a glow plug's always ON condition.

Glow Plug Relay Control - California
The California glow plug system is composed of solid state Glow Plug Control Module (GPCM), glow plugs and the associated wiring harness. The
glow plug on-time is controlled by the Powertrain Control Module (PCM) and is a function of oil temperature, barometric pressure and battery
voltage. The PCM enables the GPCM which drives the individual glow plugs. Glow plug on-time normally varies between 1 to 120 seconds. In
addition to PCM control, the GPCM internally limits the glow plug operation to 180 seconds regardless of PCM commanded on-time. The power to
the glow plugs is provided through the GPCM solid state drivers directly from the vehicle battery. The GPCM monitors and detects individual glow
plug functionality, and the control and communication links to the PCM. The failures detected by the GPCM are passed to the PCM using a serial
communication signal on the diagnostic line.
NOTE: Wait to start lamp on-time is independent from GPCM on-time.

Quote:

Originally Posted by Colorado350 (Post 18415996)

Billy, how do the two differ in functionality? Any chance he has a spare to swap out?

GPR is old school mechanical. The GPCM uses PCB parts (Electronic) to give power to the glow plugs. At least that's how I see them.

I already asked if he still had his old one. Even if it didn't light the glow plugs themselves, it would at least let the truck run and shut off normally. But the old one made its way to the trash bin.

Quote:

Originally Posted by BillyBob69 (Post 18415804)

Hi Billy, sorry for the confusion. I didn't realize his E99 was a Cali truck. My build date is about the same but is a Federal truck and has the actual mechanical GPR. Looking through the wiring diagrams for the model 99 it seems as it would have the same issue as the OBS trucks. Unfortunately I don't have a wiring diagram for the E99 Cali version so no big help here. I did look at the 2001 - 2003 models with the GPCM and can't find any feedback circuit as described which would cause the engine to do as indicated.

Quote:

Originally Posted by Hussler (Post 18416211)

His next day off is Tuesday so gonna dig into it then. We are going to start with the ignition cylinder, rod and switch first. Hopefully we can find the issue.

Makes me more thankful mine isn’t a California E truck.

MY '00 GPCM completly failed and didn't set any codes.. Just didn't work. Swapped with one for a 6.4 and it was all fixed (GPs worked). So dont
trust it to set codes.

If the truck wasn't garaged I would have a tough time starting it if its wasn't plugged in for several hours even in moderate cold.

Is there a known way to test the module to see if it has failed or...???
Pin-out maybe to at least test for continuity?

Thanks!

Id stsrt with ignition as well. My buick (01) does the same thing. I just re insert the key to reset the tumbler or whatevers wonky inside. I can remove the key going down the road and she still runs

Quote:

Originally Posted by BillyBob69 (Post 18417106)

Is there a known way to test the module to see if it has failed or...???
Pin-out maybe to at least test for continuity?

Thanks!

Billy, really can't find any documentation regarding the GPCM installed on the E99 or 99.5 trucks, Federal or Cali. Of course I could be wrong, usually am. I know the 96, 97 OBS Cali versions used a different version on the GPR with big shunts on the relay for feedback to the PCM for emission control with more wires connected. A picture of his GPCM module would clear this up quickly.