I have a 1984 Ford F350 with a 6.9L Diesel. I recently had the glow plugs, glow plug controller and sensor replaced. Now the glow plug light will only come on win the engine is cold. If the engine is warm, around 190-200 degrees, it fires up just fine. If it is colder than 190 degrees, the glow plug light does not come on and the truck is difficult to start. I was told that the sensor is working properly and that the problem is that the engine doesn't have enough compression. The truck has 100,000 miles on it.

Any help on what to do next would be greatly appreciated.

 

Thats strange, mine will fire even if its only luke warm. My understanding is that the GPs should stay off if the engine is warmer than 90 degrees.

Was anything else changed with the glowplugs (parts or settings)?

How did the glow plug system work before the new parts (during warm restart)?

 

can you do a glow plug controller bypass on an 84, or is the system not set up for this? I have read that later models the bypass works fine, but the older models have the after-start cycling (to reduce startup smoke) and you shouldn't bypass them.

 

What brand of GPs were installed.........Champion will burn up in a few days sometimes..... also if the controller stick on it will toast them too.

You can do a manual pushbutton for the GPs on the 84-86 trucks.

Ziggster's page

 

I don't care what brand of GP you use, as long as it is a dual coil temperature limiting version. UI personally like AC 12G or Autolite 1109 because I have personal experience with them. I recommend heating whatever GP you chose before you install them. That way you can prevent an infant mortality in your engine where it could be catastrophic. It also gives you an idea of how fast they heat up. They put GP controllers on for the wooseys that wanted to drive a 'Diesel'.

I've heard good things about BERU ZD9 GPs. I think they may be dual coil temperature limiting. Their website talks a lot about the dual coil design.