Really need your help.
Thread Starter
|
New User
Joined: Sep 2018
Posts: 2
Likes: 0
Really need your help.
Hi there. I hope some of you gurus can help me. I have a 92 F250 with the 7.3 diesel and sidewinder turbo on it. I’ve started to have problem with my glow plugs....yes, the infamous GL relay just clicking on and off instead of running through the heat cycle before starting. So I’ve replaced the glow plugs with 2 sets of motor craft plugs. I have replaced the harness and glow plug connectors. And I even put in a new controller and relay module. All my plugs test out at 0.5 ohms or so. All my connectors are solid. All wires in the new harness have continuity (I built the harness myself with 10 guage auto wire). All connections in harness are soldered. All the grounds on the engine and chassis are good. Batteries are at full charge. And it’s still just clicking. Truck has not been started in two weeks or so.
So, for the life of me, I can’t figure out what’s going on. I also might add I’ve been an electrician for 27 years with extensive motor control experience. So I’m pretty good with this stuff.....usually. Any ideas???
So, for the life of me, I can’t figure out what’s going on. I also might add I’ve been an electrician for 27 years with extensive motor control experience. So I’m pretty good with this stuff.....usually. Any ideas???
Lead Driver
Joined: Apr 2008
Posts: 6,945
Likes: 13
Seems unlikely, but bad electrical components right out of the box isnt unheard of... Would say its about got to be a ground issue. Have you tried bypassing the controller and verifying that the glowplugs will heat? Rules out bad ground / connections within the harness and plugs. If you get heat bypassing, has to be controller, controller wiring, or power into controller.
Side note, had the same issue on mine, found out that apparently a shop had bypassed the engine connector for the GP wires, known to corrode / short out. When they did so, they buried a couple 50 amp breakers in electrical tape under the fuse box. They couldnt handle the load and would open, causing my relay to click also. Ford specs the GP circuit to draw 207 amps if memory serves. Secondly, the power wires from the fender solenoid to the controller are fusible link near the solenoid.
Side note, had the same issue on mine, found out that apparently a shop had bypassed the engine connector for the GP wires, known to corrode / short out. When they did so, they buried a couple 50 amp breakers in electrical tape under the fuse box. They couldnt handle the load and would open, causing my relay to click also. Ford specs the GP circuit to draw 207 amps if memory serves. Secondly, the power wires from the fender solenoid to the controller are fusible link near the solenoid.
Thread Starter
|
New User
Joined: Sep 2018
Posts: 2
Likes: 0
Thanks for your great answer. I actually just came in the house after finally fixing it.
I was thinking about bypassing the controller when I realized I hadn’t checked the relay voltage under load. So I shunted the relay coil ground and the voltage on the line side of the relay contact disappeared. Aha!!!! Either a corroded connection or half-burnt fuse. So I opened the fuse box and started wiggling stuff. Then I heard the relay engage and some smoke came from the main harness connector. So I shut the ignition off and hidden underneath the connector was a melted spot. Finally....found the problem. At that time the heavens opened and I heard the angels sing. Anyway, I cut the GP feeder wires and soldered on hefty connectors. And the system started working normally again. Put it all back together and the truck started faster than it ever has.
This is something that I hadn’t found while researching the problem on the internet: If the supply voltage going to the relay contacts is bad, it will cause the relay to short cycle just as if there are bad plugs. Good to know.
Also, always check voltages under load too.
I was thinking about bypassing the controller when I realized I hadn’t checked the relay voltage under load. So I shunted the relay coil ground and the voltage on the line side of the relay contact disappeared. Aha!!!! Either a corroded connection or half-burnt fuse. So I opened the fuse box and started wiggling stuff. Then I heard the relay engage and some smoke came from the main harness connector. So I shut the ignition off and hidden underneath the connector was a melted spot. Finally....found the problem. At that time the heavens opened and I heard the angels sing. Anyway, I cut the GP feeder wires and soldered on hefty connectors. And the system started working normally again. Put it all back together and the truck started faster than it ever has.
This is something that I hadn’t found while researching the problem on the internet: If the supply voltage going to the relay contacts is bad, it will cause the relay to short cycle just as if there are bad plugs. Good to know.
Also, always check voltages under load too.
Thread
Thread Starter
Forum
Replies
Last Post
snowcrash47
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
22
May 2, 2012 01:26 PM
Scout
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
4
Jan 2, 2006 05:23 PM
