Baxter
Registered User
Hey everyone, I know there is a lot of glow plug discussion on here but I'd like to explain my situation and see if any solutions come up besides bypassing it to a manual switch ... sorry for the long winded explanation.
1985 stock 6.9, truck became hard to cold start after about a year of normal operating and glow plug light wouldn't come on, just cranking and cranking forever so I replaced the gp relay unit ... fixed, so I thought, everything was back to normal... then couple weeks later same no cold start issue so I replaced all the glow plugs with motorcraft brand and still nothing on cold ... I should mention truck has always started right up and ran fine when warm. So now I replace the controller about a month ago, the solid state unit in the back of engine bay screwed into engine block. Fixed so I thought, everything back to normal, gp dash lights up and cycles thru normal, on for about -5 sec. off and back on for 5 sec. etc. there is also an audible clicking noise each time it lights up which has been normal since I've owned the truck, crank it and it fires right up quick, cold.
Now all of a sudden on a warm start the other day the gp dash light stays on indefinitely and there is no clicking sound. Truck starts easy because it's warm.. I then disconnect the relay so as to keep the plugs form burning up if they were permanently hot for some reason. Get home and sit over night to a cold start situation in morning...and nothing just cranks and cranks and light stays on indefinitely. Replaced the relay again because I had a new unopened one. Same, nothing. Tested a couple of the glow plugs and they appear to be dead. Was now going to replace the controller and plugs again but that feels stupid.
Questions:
1. What would the difference be between light not coming on at all and light staying on and not going off? both are accompanied with no start situation.
2. Is the standard clicking noise that is no longer there, coming from the relay unit or the controller?
3. All new components, relays, controller (Standard brand lifetime warranty) and glow plugs (Motorcraft) why would they fail so quickly?
4. Haven't installed an all new wiring harness yet, didn't think that would be the culprit ... looks in good condition wires, clips etc. would that cause any of this ****?
5. Is there an easy away to test the relay, controller and the harness in place on the engine before I throw more at it?
Thanks for your help!
1985 stock 6.9, truck became hard to cold start after about a year of normal operating and glow plug light wouldn't come on, just cranking and cranking forever so I replaced the gp relay unit ... fixed, so I thought, everything was back to normal... then couple weeks later same no cold start issue so I replaced all the glow plugs with motorcraft brand and still nothing on cold ... I should mention truck has always started right up and ran fine when warm. So now I replace the controller about a month ago, the solid state unit in the back of engine bay screwed into engine block. Fixed so I thought, everything back to normal, gp dash lights up and cycles thru normal, on for about -5 sec. off and back on for 5 sec. etc. there is also an audible clicking noise each time it lights up which has been normal since I've owned the truck, crank it and it fires right up quick, cold.
Now all of a sudden on a warm start the other day the gp dash light stays on indefinitely and there is no clicking sound. Truck starts easy because it's warm.. I then disconnect the relay so as to keep the plugs form burning up if they were permanently hot for some reason. Get home and sit over night to a cold start situation in morning...and nothing just cranks and cranks and light stays on indefinitely. Replaced the relay again because I had a new unopened one. Same, nothing. Tested a couple of the glow plugs and they appear to be dead. Was now going to replace the controller and plugs again but that feels stupid.
Questions:
1. What would the difference be between light not coming on at all and light staying on and not going off? both are accompanied with no start situation.
2. Is the standard clicking noise that is no longer there, coming from the relay unit or the controller?
3. All new components, relays, controller (Standard brand lifetime warranty) and glow plugs (Motorcraft) why would they fail so quickly?
4. Haven't installed an all new wiring harness yet, didn't think that would be the culprit ... looks in good condition wires, clips etc. would that cause any of this ****?
5. Is there an easy away to test the relay, controller and the harness in place on the engine before I throw more at it?
Thanks for your help!