Start problem New engine, no wait light new GPC

[lowstature]

1990 6.2 diesel was replaced with a "new" Military 6.2. diesel. Before we switched out the engine, it started fine (glow plugs cycled and wait light worked). New engine is in and the wait light does not turn on. The engine and truck have new glowplug controller, new glow plugs, new injector pump, new injectors etc. I replaced the fuel filter (This is the rectangle one with the preheat looking stuff) and we cycled fuel thru all the lines so there isn't air in the fuel system.

I can spray carb cleaner in the intake to get it started, once started, she runs fine. She performs well and operates normal. I can let her run for 30 minutes and take her up to full speed no problems. If I shut her off, she won't start again without carb cleaner. We originally had the injector pump advanced, but have tried top dead center and everything in between up to about a 36 degree advance with no change in the results.

We thought it must be an electrical issue and I was told this is the breakdown of the pins at the glow plug controller: 1- ground (one end of the five) 2- ignition switch, 3- glow plug inhibit switch, 4- engine starter input, 5- not used.

I should have 12 volts at the center pin when energizing or cranking if I understand that breakdown correctly. I do not have 12 volts at the pin, so I checked all fuses... They are all good.

Any ideas on why she won't start on her own power?

[john8662]

Is the glow light coming on at all?

If no, then it's very possible that you're missing a ground wire in the circuit. I've had this happen before.

But, when the engine is warm, it should start without glow anyways...

J

[Peter J. Bierman]

What about the inhibitswitch? If it "thinks" the engine is hot it will break the circuit and the controler willnot cycle.
You can try a jumper to the glow relay to check ifthe relay and plugs are good.

The glow system is from the truck right? otherwise the millitairy system is might be the problem, it works a bit different.

I have to agree with John that when warm the engine should start anyway.

Peter

[ccatlett1984]

just ditch the factory controller and put in a manaul push button for the gp's.

on the glow plug relay under the hood there is two small terminals, one will have 12v hot with the igntion on, the other is the ground. The ground wire is switched to activate the glow plugs. Just run one side of your push button switch to the ground terminal on the relay and the other side to a good ground on the truck.