Macrobb
Full Access Member
OK, so I've got an interesting one here:
In my 93, the glow plugs stay on for a very very long time before cycling. Like, I can turn the key on, hear GPC click on. Wait for 10 seconds, WTS light goes out. GPC still on. Wait for another 30 or so seconds... GPC finally clicks off and that's it. No cycling.
Key off and back on. Does the exact same thing. On the third key cycle(with the GPs finally hot), it'll start cycling off and on.
Now... After a single key-on cycle(~30s), it won't instantly start. If I wait for two key-on cycles, it'll fire right up within 5 revolutions.
I've replaced the actual GPC relay with a new one; with the GPC actuating it, there's about a 0.5V drop across the relay. I think 1.2V from battery to GPC output terminal(including drop across the resistor).
Now, I know all 8 glow plugs are Motorcraft ZD9s, all of them recent. It's done this for a while now, but because it's always worked and fired right up, I haven't worried about it.
I'm trying to figure out what's wrong. It's like... something past the GPC is preventing current from flowing and the GPs aren't getting hot quickly.
Oh, I also checked voltage from block to B- and GP controller ground to B- - less than 0.1V when GPs are on.
Any ideas on what to try?
In my 93, the glow plugs stay on for a very very long time before cycling. Like, I can turn the key on, hear GPC click on. Wait for 10 seconds, WTS light goes out. GPC still on. Wait for another 30 or so seconds... GPC finally clicks off and that's it. No cycling.
Key off and back on. Does the exact same thing. On the third key cycle(with the GPs finally hot), it'll start cycling off and on.
Now... After a single key-on cycle(~30s), it won't instantly start. If I wait for two key-on cycles, it'll fire right up within 5 revolutions.
I've replaced the actual GPC relay with a new one; with the GPC actuating it, there's about a 0.5V drop across the relay. I think 1.2V from battery to GPC output terminal(including drop across the resistor).
Now, I know all 8 glow plugs are Motorcraft ZD9s, all of them recent. It's done this for a while now, but because it's always worked and fired right up, I haven't worried about it.
I'm trying to figure out what's wrong. It's like... something past the GPC is preventing current from flowing and the GPs aren't getting hot quickly.
Oh, I also checked voltage from block to B- and GP controller ground to B- - less than 0.1V when GPs are on.
Any ideas on what to try?
https://www.oilburners.net/threads/glow-plug-solutions-from-classic-diesel-designs.84824/
