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Discussion Starter #1
Buddy of mine says his GPR is not coming on at all. Replaced it with a NAPA GPR and still the same thing.

Any suggestions?

I did look in the archives and found what the wires on the GPR were supposed to be doing with the key off, key on and running.
I have not been under his hood so can not answer any questions as of now.

Just need some ideas to give him.
TIA
 

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Pcm controls it.
Need more info.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

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Discussion Starter #3
what kind of info?

Is there a timer on the pcm or is there a sensor to tell it when to turn off?
 

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Like: is power getting to the GP relay?
Ambient temperature?

Pcm relies on EOT and BARO sensor for glowplug operation.

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This is one of those interesting things I came across in the service manual:

Ford said:
Glow Plug Relay

The glow plug relay (12A343) has a plastic base and two mounting bolts. It is operated by the powertrain control module (PCM) (12A650) which senses engine oil temperature, PCM voltage and barometric pressure.

When the engine oil temperature or the barometric pressure is low, the PCM activates the glow plug relay and the glow plugs.

If the PCM voltage is too high, the powertrain control module deactivates the glow plug relay and the glow plugs immediately energize for a shorter duration, decreasing the modulation of the duty cycle.
Ford said:
10. Glow Plug System Operation


Recommended Procedure:
Relay Operation
Install a DVOM on the glow plug feed side of the glow plug relay (large stud with two wires connected). Turn the ignition key to the ON position but do not attempt to start. Note the time in seconds from when the key is turned on and the glow plug relay energizes until the glow plug relay de-energizes. The glow plug relay makes a loud click noise which is easily heard when it energizes and de-energizes. The dome light will dim and the dash voltmeter will dip when the glow plugs are drawing current from the battery. Compare the times measured to the table (time will be affected by engine temperature, battery condition and vehicle altitude). The voltage at the glow plug feed terminal may vary from 9 to 12 volts depending upon battery condition.


If battery voltage is not present, check for B+ at the power supply terminal (terminal with single large wire). Power for glow plug power supply is supplied from the starter relay through two fusible links at solenoid.

Glow Plug Operation
Disconnect all of the glow plug/injector harness connectors from the valve cover gaskets. With the Rotunda Glow Plug Injector Adapter 014-00935 or equivalent installed, measure glow plug resistance to ground (preferably B-). A resistance measurement of 0.1 to 2 ohms indicates a good glow plug.


Glow Plug Harness Continuity
Measure for continuity from the connector harness to the glow plug feed terminal on the glow plug relay. Resistance should be less than 0.1 to 1 ohm.

Incorrect measurements will result if all glow plug/injector connectors to valve cover are not disconnected.


Possible Causes:
Insufficient glow plug ON time will not allow enough heat to accumulate in the combustion chamber to easily facilitate starting. If the glow plug system ON time does not meet any of the specifications in the accompanying chart the problem is most likely a faulty wire harness connection, ground connections or glow plug relay.

If the glow plug resistance to ground is high, the most likely causes are an open under valve cover (UVC) harness or an open glow plug.

Tools Required:
Rotunda Digital Volt-Ohm Multimeter (DVOM) 105-00050 or equivalent
Rotunda Glow Plug Injection Adapter 014-00935 or equivalent
Stop watch or equivalent
 
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Discussion Starter #6
Thanks, for all the suggestions will get back to you with problem as soon as I can.
 
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