Hi guys,
I have an '04 F250 with the 6.0 and I'm having a problem where the glow plugs are staying on until the ECT reaches somewhere north of 180 degrees. The truck starts and runs fine but on short trips this is really running my batteries down. I can see the voltage jump back up once the glow plugs finally shut off, the question is what is causing them to stay on so long. I'm thinking perhaps a defective EOT sensor but that's just a guess. Living in Florida it never really gets cold here where the glow plugs should be on for any length of time. Any suggestions would be appreciated.

 

Have you checked you ficm. I think that's a place i would start and check the relay under you hood as well

 

Yes, I have had the ficm rebuilt fairly recently and have also replaced the glow plug control module. Not sure where to turn next.

 

When you turn the key on how long does the glow plug light (on the dash) stay on for how long can you hear the relay clicking for?

 

The dash light only stays on for 10-15 seconds. I don't hear the relay click over the engine noise. But watching the voltmeter while driving it's a good 10 minutes or so until the relay opens and the voltage jumps back up over 12. At that point the ECT is over 180 degrees.

 

Witch relay are you talking about? Have you tried to replace just that relay before you start the truck key on not turning it over you should hear a clicking noise no noise glow plugs go off so does the light on dash go off glow plugs should be off then as how it is on my truck are you sure it's the glow plugs staying on

 

How old are your batteries? If they are going bad it could give the long time to recharge symptom.and are you sure your alternator is functioning properly?

 

He rite bout that and tell them to disconnect the battires when they test them i had a bad battery test them twice good third time tested alone one battery was bad

 

The relay I am talking about is the glow plug control module. The batteries are new, this issue is what killed the last set, which were 2 years old. The alternator is new as well. Had the same issue today, the ECT was 188 degrees and EOT 194 degrees when the glow plugs finally shut off and the voltage jumped up to 13.5 while running. I guess I need to take it to the shop to get it fixed unless someone has an idea of what the culprit could be.