Glow plug/pcm issues
Postmaster
Joined: Nov 2005
Posts: 3,168
Likes: 10
From: San Ramon Ca.
Just a cautionary statement. A new part doesn't mean it's a good part. The voltage drop across the relay / feed to the glow plugs has to be within the specs Jim posted or it throws a code. If the code is stored on the PCM and doesn't go away after you clear all codes that is not a bad thing. They are just stored on the PCM. Not a problem. It might be a good idea if your issue doesn't go away to replace the shunt. Not a big ticket item. Otherwise OHM out the glow plugs. Someone will come up with a proper reading as I don't remember of the top my head. If the truck starts OK with no white smoke I would say your good to go. If you get white smoke and the engine is slow to start there is a problem.
FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
Just a cautionary statement. A new part doesn't mean it's a good part. The voltage drop across the relay / feed to the glow plugs has to be within the specs Jim posted or it throws a code. If the code is stored on the PCM and doesn't go away after you clear all codes that is not a bad thing. They are just stored on the PCM. Not a problem. It might be a good idea if your issue doesn't go away to replace the shunt. Not a big ticket item. Otherwise OHM out the glow plugs. Someone will come up with a proper reading as I don't remember of the top my head. If the truck starts OK with no white smoke I would say your good to go. If you get white smoke and the engine is slow to start there is a problem.
each connector has 5 pins
1 2 3 4 5
- - - - -
1 and 5 are glow plugs. Assuming the glow plugs are good with an ohm meter, black lead on battery ground and red lead on either pin you should have 10 or less ohms. preferable 5 or so. if it reads OL (out of Limits) either you have bad wiring or a bad glow plug at which time you need to do the same test but at the top of the glow plug and not the connector.
Then to test the other three terminals with the black lead on 3 and the red lead on either 2 or 4 you should have 3.5 ohms plus or minus a few tenths. the pin 3 is common for those two injectors. If you have more resistance than that you have wiring or injector solenoid issues and the valve cover needs to come off.
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New User
Joined: Aug 2013
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ok, I tested the gpr and the shunt passed no problems. If I did this correctly and understood it correctly, I tested the ohms at the connector that goes under valve covers that go to the glow plugs; I put my black wire on the neg. at the battery, and the red to the 1'st pin and then the fifth pin, my digital meter went from 1-0 (1 when not touching anything and 0 when I touch both leads) when I touched them. Then I put the red on both pin 2 and 4, black on pin 3 meter went from 1-0.2. So my question is did I do this correctly? and if I did it sounds to me the glow plugs or injector solinoids are bad?
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New User
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GPR volts: in 11.8 out 11.6. Tested the ohms at pins 1 and 4 (setting at the 200, wont read at any other setting), got 0.7. Tested pins 3 and 4, got 3.3. Brand spanking knew batteries and cables and are fully charged. I do have one other thought, could by any chance the oil temp sensor throw a GP code even if it's not throwing a Oil Temp Sensor code? Thanks again for all your thoughts, suggestions and ideas.
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
At a loss for what?
No, EOT sensor won't throw a glow plug code. What resistances are are you measuring, valve cover connectors? If so ...
Pin 1 to battery ground = one glow plug
Pin 5 to battery ground = other glow plug
Pin 2 to pin 3 = one injector solenoid (pin 3 is injector ground)
Pin 4 to pin 3 = other injector solenoid (pin 3 is injector ground)
Re-measure and report back.
No, EOT sensor won't throw a glow plug code. What resistances are are you measuring, valve cover connectors? If so ...
Pin 1 to battery ground = one glow plug
Pin 5 to battery ground = other glow plug
Pin 2 to pin 3 = one injector solenoid (pin 3 is injector ground)
Pin 4 to pin 3 = other injector solenoid (pin 3 is injector ground)
Re-measure and report back.
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I am at a loss for what to do next....
I am measuring at the valve cover connectors, and I did a type err, I met 1 and 5 not one and 4, my apologies. I had it set at the 200 with a reading of .7, and pins 3 and 4 a reading of 3.3. thank you.
Just one side note, these batteries are brand knew, however the truck seems to turn over ok with the starter but when I did do these tests the first time I made sure the batteries were fully charged with a charger and they were slightly low. took about 40-60 mins. to charge up. It seems like I had read somewhere (have read so much stuff on this issue, I could be wrong) that a bad starter could cause a glow plug issue as well as drain down the batteries. Just trying to think outside the box.
I am measuring at the valve cover connectors, and I did a type err, I met 1 and 5 not one and 4, my apologies. I had it set at the 200 with a reading of .7, and pins 3 and 4 a reading of 3.3. thank you.
Just one side note, these batteries are brand knew, however the truck seems to turn over ok with the starter but when I did do these tests the first time I made sure the batteries were fully charged with a charger and they were slightly low. took about 40-60 mins. to charge up. It seems like I had read somewhere (have read so much stuff on this issue, I could be wrong) that a bad starter could cause a glow plug issue as well as drain down the batteries. Just trying to think outside the box.
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