I have changed all my Glow plugs and I'm still not getting full time from my wait to start light, and its not starting very quickly. Would I want to start by replacing my GP Controller? What will the GP relay do when it goes bad?

 

What year truck - you really need to put your truck info in your sig.

Generally the relay will either work or it won't. If your's is the old style (pre 87) system like mine, then if the relay doesn't work then the WTS light won't come on at all. Sounds like yours is coming on for at least a short time. If your's is like mine, then I'd say it is probably the controller.

I've seen the controller on eBay for as little as $60 + shipping. Or you can always do the pushbutton controller bypass mod.

 

Two different glow plug systems, completely different from each other.

What kind of glow plugs did you install?

 

I have added my truck info to my sig. Its a 1990 non turbo IDI 7.3L. The glow plugs I installed are the Ford's that are made in Germany. Autozone $9.99 a pop. I have looked on Ebay. That seems to be the best price.

 

How'd you know what year and system he has, Dave? I don't see it anywhere in his post or his sig line.

Don't tell me you're a clairvoyant IDI savant

 

Naaa he just cheated a little and looked on public profile..

Just click on the name and a menu will come down one of which is public profile.

 

If you have the older controller set-up. It is an aluminum controller that is about 3 inches tall. Goes into the motor on the back right corner. Don't buy one. I will give you one to try. All that stuff went by-by off of my engine. I have my own design now. Had the same glows plugs for 8 years. No problems. You are more then welcome to it. Happy Thanksgiving

 

AHAA!! I didn't realize that stuff could be in the profile without showing up in the sig line. Useful to know.

Per ALLBOY's profile, and Dave's post, his truck is a 1990 - and therefore a different system.

I have the style controller you're talking about, and just replaced it with a nearly new one I got from my buddy. Sounds like you've done something more than the plain-jane pushbutton to replace yours. Since mine will go out again eventually (I'm sure) I'd be interested in hearing more about what you've done.

I retained the stock controller instead of cutting it completely out of the loop. I just interrupted its signal to the relay with a NO pushbutton. That way it can't "lock on" and burn out my GPs, but I still retain the timer function, and temp-based cycle or no cycle functions. I just have to hold down the pushbutton when starting it.

 

Ummm, if you read my post again you will see that I was asking for the year since there were two different glow plug systems.


Actually I am psycho......I mean psychic.


Check the ground wire on the controller.
Black wire probably under one of the relay/controller mounting bolts.
Remove the bolt and clean everything so it is getting a good ground.

Also on the passenger side of the engine near the dip stick, there is a connector where the engine harness plugs into the chassis harness. Examine it for signs of overheating. If you do not see any, unplug it and check the condition of the connectors inside, the two large wires on one end will be power to the glow plug relay.



I forgot the picture.

If it does show signs of overheating, you should just cut the two big wires on each side of the connector as close to the connector as possible and splice the wires together. If you take it apart, you may not get it back together again.

You have the new style system which uses resistance feedback to time the glow plug cycle. Any variation on the ground or power supplied will affect the heat time cycle.

You should also inspect all the battery connections from the positive terminal to the relay and the glow plug harness connection to the relay. Anything that looks like it may not be making a good connection needs to be cleaned.

 

While your at the black wire Dave S. is speaking of . Run an additional wire from the black one under the bolt to the (-) post of the battery. I've found this helps later on when corrosion sets in again so you have a good ground to operate the controler. Be sure to use a larger wire than the black one.

 

I re-did mine by undoing it. I kept having troubles a few years back. I can't say for what year but GM was still selling 6.5's because I was going to use a GM controller cause I worked at a dealer that carried the GM 3500HD's and up so I could get them pretty cheap. We never really saw problems with the system they used at the end of the 6.5 days. I ended up putting on a regular ole Bosch relay, run the control circuit to a switch in the dash and let it ride. I heat them if I felt like I needed to. I can go in a store, during the summer, for a couple of hours and come out a start her up and go. I time them in my head and go with it. I put AC 8G's in the motor back then and they are still in there.I used a spring loaded switch that can't be accidently be tripped and the ignition has to be in the run position. Later.

 

I just redid mine with a switch. It's a toggle on the dash; momentary contact, off and maintained contact. I leave it in the middle and hold it on to start up cold, timing it out like catfish. The rest of the time it's off. The wife can put it down and let the relay run automatic if she wants [ discouraged behavior ]. As an extra it makes it harder to steal the truck unless it's warmed up.