did I smoke this gpc

[bj_idi]

ill start this off by saying engine is running great and this forum is awesome, I could not have done that build without the knowledge here. Also the parts and freeze plug tool you guys helped me out with, thanks everyone!

ok I live in south fl and I was not happy with how long my glow plugs were coming on for. had the bright idea to break ground, via switch on dash to turn off glow plug controller . long story short I used the switch a few times with great success, then it was spotty, and now no gpc function. Removed that switch entirely after having the issue (lug back at intake stud. good ground). have no WTS light.

key off - 12.2v @ main term from battery(@Glow plug relay)
key on - 11.6v @ term with small red wires(@Glow plug relay)
key on - 11.6v @ term with white wire (@Glow plug relay)

rung out harness/plugs-ok

all glow plugs are new motorcraft zd9 beru. was working before messing with it. any other tests I can do?

edit: also for 7.3 do you guys prefer momentary push button or to have a good working controller?


thanks

 

[pelky350]

IVe been using manual switch for years now, it's just natural at this point for me. My glowplugs only get cycled like two times a day now before and after work but when running around and trucks warm I never need them to start it and I do many start stop trips all day. So for me it probably is extending the life of the plugs quite a bit but everybody has their preferences

 

[franklin2]

Manual pushbutton for me also. Simpler is better.

 

[snicklas]

Ok, so if I am reading this right, you left everything connected per factory, except you are now providing the small white wire ground to the relay with a new wire/switch into the cab, and now the glow plugs don’t cycle at all, correct?

If this is how you have it connected, I would disconnect your new ground, and replace the factory wire, and see if glow plug function returns to normal. If so, the issue is in your new wiring. If the function doesn’t return, I would jump the white wire post to ground, for a few seconds and see if triggering the relay results in an easier start. If so, the controller isn’t triggering the relay,so it may be your controller, the wiring.

Once you figure out what’s happening, I would then decide how you want the system to work. Either full manual 100% of the time, or work like factory with a manual override to trigger them if the controller doesn’t. I’m not sure it’s a good idea to interrupt the controller during operation. With your setup, pulling just the ground, it’s the same as just yanking the plug on a piece of electronics....... eventually that’s going to kill something......

What I and others have done, as a backup, is leave the wiring and function 100% stock, but add an additional wire to the white ground wire post, with a momentary push button in the cab to ground. This way, if the controller just starts cycling and not heating due to a bad glow plug or 3, you can manually run the ones that are left and start the truck with 5 or 6 plugs. Or, I’m my case, occasionally, the controller doesn’t do anything, no cycle, no clicking, just sits there. I can push the button, slow count to 7 or 8 and hit the key. But I don’t think I would ever set it up in a manner too just pull the rug out from under it, so to speak.......

 

[DaveBen]

Scott is correct in that you don't want to interrupt the controller by pulling the ground. This could cause more problems just like yanking the plug in your computer at random.

 

[bj_idi]

IVe been using manual switch for years now, it's just natural at this point for me. My glowplugs only get cycled like two times a day now before and after work but when running around and trucks warm I never need them to start it and I do many start stop trips all day. So for me it probably is extending the life of the plugs quite a bit but everybody has their preferences

thats pretty much all I need them for, she fires right up warm. I think its headed in that direction.

Ok, so if I am reading this right, you left everything connected per factory, except you are now providing the small white wire ground to the relay with a new wire/switch into the cab, and now the glow plugs don’t cycle at all, correct?

If this is how you have it connected, I would disconnect your new ground, and replace the factory wire, and see if glow plug function returns to normal. If so, the issue is in your new wiring. If the function doesn’t return, I would jump the white wire post to ground, for a few seconds and see if triggering the relay results in an easier start. If so, the controller isn’t triggering the relay,so it may be your controller, the wiring.

Once you figure out what’s happening, I would then decide how you want the system to work. Either full manual 100% of the time, or work like factory with a manual override to trigger them if the controller doesn’t. I’m not sure it’s a good idea to interrupt the controller during operation. With your setup, pulling just the ground, it’s the same as just yanking the plug on a piece of electronics....... eventually that’s going to kill something......

What I and others have done, as a backup, is leave the wiring and function 100% stock, but add an additional wire to the white ground wire post, with a momentary push button in the cab to ground. This way, if the controller just starts cycling and not heating due to a bad glow plug or 3, you can manually run the ones that are left and start the truck with 5 or 6 plugs. Or, I’m my case, occasionally, the controller doesn’t do anything, no cycle, no clicking, just sits there. I can push the button, slow count to 7 or 8 and hit the key. But I don’t think I would ever set it up in a manner too just pull the rug out from under it, so to speak.......

You were reading that correctly, the only thing differently was that I literally just broke the black ground wire with a switch. 100% pulled the rug out from under it and I believe with consequences! Have since returned everything 100% back to factory and have no function. no click or clicking no voltage drop, nothing. have confirmed good ground, good plugs and good harness. seems like no output from control module. I jumped ground to the small white wire and the plugs did come on but did not cycle the relay when released, it stuck on until I cycled the ignition (about 10 seconds-73 degrees) started right up.

when you jump that small white wire to ground does it read resistance? was the controller keeping it on or did the relay stick. no WTS light during that process

edit: tomorrow will take the factory white wire off post then jump to ground and see if relay goes open after releasing. will put wts light there if all good and put momentary.. Thanks!!

 

[franklin2]

The brain in the controller grounds the glowplug relay with the white wire. Take the white wire off, the brain has no control anymore. Put a new wire where the white wire was, with a switch to ground, and now you have control over the relay. I would put tape on the original white wire when you take it off, just for insurance that it doesn't fall against anything with bad consequences.

 

[bj_idi]

The brain in the controller grounds the glowplug relay with the white wire. Take the white wire off, the brain has no control anymore. Put a new wire where the white wire was, with a switch to ground, and now you have control over the relay. I would put tape on the original white wire when you take it off, just for insurance that it doesn't fall against anything with bad consequences.

Did that first thing this morning, now have control of the relay! Believe I hurt the controller pulling the ground. Its going to stay like this for a while, the simplicity is nice and being able the cycle them when I want. Thanks for all the help!

 

[Macrobb]

Switch the /power/ wire into the controller, the one that's switched power from the key. That way you don't end up 'backfeeding' power through the controller with the lack of grounding.

 

[franklin2]

Switch the /power/ wire into the controller, the one that's switched power from the key. That way you don't end up 'backfeeding' power through the controller with the lack of grounding.

? The way he did it is the proper way for the newer style controller. I believe you do have to switch power on the older 6.9 setup with the relay over on the pass side fender.

 

[Macrobb]

? The way he did it is the proper way for the newer style controller. I believe you do have to switch power on the older 6.9 setup with the relay over on the pass side fender.

No, not power to the /relay/, power to the /controller/. He wants(I think) a switch where "on" is "controller works normally" and "off" is "controller is disabled, no power to GPs at all"
In which case you switch the power wire going to the controller, so it thinks the key is off and therefor doesn't cycle.

 

[bj_idi]

No, not power to the /relay/, power to the /controller/. He wants(I think) a switch where "on" is "controller works normally" and "off" is "controller is disabled, no power to GPs at all"
In which case you switch the power wire going to the controller, so it thinks the key is off and therefor doesn't cycle.

that was the original plan for it to come on automatically and have the ability to turn them off via switch, but I believe I hurt the controller pulling the ground wire while it was cycling plugs, then it was a dead controller. I'm now just running momentary switch to white wire terminal everything checks out ok

 

[franklin2]

No, not power to the /relay/, power to the /controller/. He wants(I think) a switch where "on" is "controller works normally" and "off" is "controller is disabled, no power to GPs at all"
In which case you switch the power wire going to the controller, so it thinks the key is off and therefor doesn't cycle.

Not sure that will work. If you switch power to the ignition power controller input, then the relay has no power on it's + side of the coil. I do not think the + battery power for the glowplugs which is bolted to the large lug on the glowplug relay, powers the + side of the coil. I believe it's the ignition switch power that powers that and the brain of the controller.

 

[Macrobb]

If you switch power to the ignition power controller input, then the relay has no power on it's + side of the coil. I do not think the + battery power for the glowplugs which is bolted to the large lug on the glowplug relay, powers the + side of the coil. I believe it's the ignition switch power that powers that and the brain of the controller.

Exactly. So if you want to force the controller /off/ (and relay off), this is what you do.

I'm not talking about a manual setup that would allow for a push button override. Just a switch for (controller on like normal) and (glow plug system completely off)

that was the original plan for it to come on automatically and have the ability to turn them off via switch, but I believe I hurt the controller pulling the ground wire while it was cycling plugs, then it was a dead controller. I'm now just running momentary switch to white wire terminal everything checks out ok

Yeah, controller is dead. You'll need a new one. But you need to wire the new one differently to not kill it too.

 

[Psolver]

ok ok how do i bypass the controller just want glow plugs when i want them , my wait to start light keeps coming on as i drive intermittently