GPR and PCM

[89 Stroker]

lately my truck of course the GPR has been coming on even when the truck is warm, it will come on and throw a CEL at the same time, if i sit there turn the key on and off a few times it will go away and the CEL wont come on anymore nor will the GPR , any solutions? have tried it with two GPR's now.

 

[Bugman]

The GPR will come on anytime that the key is turned off and then on. It doesn't matter how hot the engine is. But on a warm or hot engine it will stay on a shorter duration than on a cold one.

If it is throwing a CEL what is the code?

 

[89 Stroker]

The GPR will come on anytime that the key is turned off and then on. It doesn't matter how hot the engine is. But on a warm or hot engine it will stay on a shorter duration than on a cold one.

If it is throwing a CEL what is the code?

im gonna go pull codes right now , just got back from driving it i shut it off then turn the key and it throws the CEL and i hear the gpr click on, if i try and start it , it barley starts, i wait a few minutes with the key off then turn it on and there is no CEL and the GPR does not come on and it fires right up.

here are the codes ist throwing now

p0197
p1391
p1393
p0113
p0380
p1280

 

[Bugman]

That is interesting in that 2 of those codes only show up on 99+ diagnostics list.

P0197 EOT sensor ckt low input Caused by grounded ckt, biased sensor or PCM
P0113 IAT sensor low input Caused by grounded ckt, biased sensor or PCM or sensor is disconnected
P0380 Glow plug ckt malfuction Caused by open/grounded ckt, solenoid open/shorted/ failed PCM
P1280 ICP ckt out of range Caused by open/grounded ckt, biased sensor, PCM

P1391 and P1393 should only be on a 99+ year truck. Together will set when the monitor indicates that all eight glow plugs are not being powered. An open in all glow plug circuits, the glow plug relay, glow plugs, fusible links or all three monitoring circuits could be the possible causes.

You do know that you can Google these codes to see what they mean and possible solutions?

 

[89 Stroker]

That is interesting in that 2 of those codes only show up on 99+ diagnostics list.

P0197 EOT sensor ckt low input Caused by grounded ckt, biased sensor or PCM
P0113 IAT sensor low input Caused by grounded ckt, biased sensor or PCM or sensor is disconnected
P0380 Glow plug ckt malfuction Caused by open/grounded ckt, solenoid open/shorted/ failed PCM
P1280 ICP ckt out of range Caused by open/grounded ckt, biased sensor, PCM

P1391 and P1393 should only be on a 99+ year truck. Together will set when the monitor indicates that all eight glow plugs are not being powered. An open in all glow plug circuits, the glow plug relay, glow plugs, fusible links or all three monitoring circuits could be the possible causes.

You do know that you can Google these codes to see what they mean and possible solutions?

yes i know, i have not got to that point yet to sit down and go through all of them but will tonight , just wanted some other input about them

 

[Lethalthreat7.3]

With all the codes indicating a possible ground fault, i would look there.
As a real quick test, run an additional ground from the motor to the chassis and retest for any codes.

 

[89 Stroker]

With all the codes indicating a possible ground fault, i would look there.
As a real quick test, run an additional ground from the motor to the chassis and retest for any codes.

so besides the existing ground to the motor run a new one to the frame and see what happens?

 

[Lethalthreat7.3]

Run it to the fender/chassis. There are several grounds but you should have one on the back top of the motor(been awhile since I looked for it) going to the fire wall. There is the one coming off the passenger side negative cable bolted around the starter relay. There is one over by the air cleaner, I believe. Can't remember but think there is one down by the frame/radiator.
Have you tried using your meter to see what kind of resistance you have between the engine and the cab?
Set your meter to ohms, perferably 0-200 scale as most meters that just have the 0-2k scale are not usually sensative enough. Take a reading. If it's good then it will read the same as touching your leads together.

 

[Lethalthreat7.3]

Running it to the frame is incorrect as the rubber in the mounts, springs and rust on bolts can cause an issue.

 

[89 Stroker]

i just checked the one on the back of the motor to the firewall is hooked up , the driver side battery has a ground going to the frame and the passenger has a ground going to the frame and going to the motor

 

[Patrick Feeley]

Just for info: If the OP's 97 conversion is from a California model truck, he could have the Glowplug Monitoring circuit(s) and have those codes show up. Cheers!

 

[89 Stroker]

the motor was pulled from a 97 Van, i am pretty sure it was from a CA van but cant remember, went out today and messed with the grounds, i took out the ford GPR and put my napa one in it and it has started 8 out of 10 times that i have tried, i changed a few fuses, switched the gpr and cleaned the connections and now the CEL does not come on like it used to, will try and see in the morning

 

[Patrick Feeley]

And just for more info, here is some stuff on the monitoring:

Glow Plug Monitor

Glow Plug Control, Comprehensive Component Monitors, and Wait to Start Indicator—California

The California glow plug system is composed of a glow plug relay, glow plug shunt strips, shunt strip monitor circuits, glow plugs, glow plug light, 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 Glow Plug Relay, which drives the shunt sense strips, which in turn drive the individual glow plugs. Glow plug on-time normally varies between 1 and 120 seconds. The power to the glow plugs is provided through the Glow Plug Relay directly from the vehicle battery. The PCM monitors through two shunt monitoring circuits, one per bank, and detects glow plug functionality.

Glow Plug Relay Control Circuit Check:
DTCs P0380 – Glow Plug Relay Circuit Check
Monitor execution: Continuous (Background 25ms – 50ms)
Monitor Sequence: None
Sensors OK: Not Applicable
Typical Monitoring Duration: Internal to Chip.

Typical Glow Plug Module Control Circuit Check Entry Conditions:
No Entry Conditions

Typical Glow Plug Module Control Circuit Check Malfunction Thresholds:
Internal to chip checks for open circuit, short to ground, and short to power.

Glow Plug Monitor Operation:
DTCs:
P1391 – Glow Plug Bank 1 Failure
P1393 – Glow Plug Bank 2 Failure
P1395 – Absolute Voltage Drop Across Bank # 1
P1396 – Absolute Voltage Drop Across Bank # 2

Monitor execution:
P1391 – Continuous
P1393 – Continuous
P1395 – During the absolute test
P1396 – During the absolute test
Monitor Sequence: None
Sensors OK: Not Applicable
Monitoring Duration:
P1395 – Greater than 30 seconds.
P1396 – Greater than 30 seconds.

Typical Glow Plug Monitor Entry Conditions:
P1391 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1393 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1395 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow Plug on time is greater than 30.5 seconds.
P1396 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow Plug on time is greater than 30.5 seconds.

Typical Glow Plug Monitor Malfunction Thresholds:
P1391 – When the Bank #1 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1393 – When the Bank #2 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1395 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts) on Bank #1.
P1396 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts) on Bank #2.

Glow Plug Wait to Start Light Operation:
DTCs:
P0381 – Glow Plug indicator circuit malfunction
Monitor execution: Continuous (Background 25ms-50ms)
Monitor Sequence: None
Sensors OK: Not applicable
Typical Monitoring Duration: Internal to Chip

Glow Plug Light Wait to Start Light Entry Conditions:
Glow Plugs Enabled

Glow Plug Light Wait to Start Light Malfunction Thresholds:
Status internal to chip

Cheers!