me and my buddy put a 94 7.3 in his 87 f350 wich had the 6.9. we made it so the glow plugs come on when he pushes a button in the cab. so do we just leave the plug alone or do we need to change it to fit?
completely bypasss the glow plug controller and replaced it with a high amp solenoid. connect your glow plug harness to one terminal of the solenoid and thick wire from positive battery terminal to the other terminal. and activate the solenoid with a manual switch.
I think the only plug you would have would be for the wait to start light which should be the same. There is an ignition wire that needs to get to the solenoid as before.
You could do as the last post says, that's how mine is, but really you already have a high amp relay on the solid state controller that's the same thing as what you would buy, and it sounds like between both engines you should have two controllers with relays mounted on top.
Check this thread for a post I just wrote with the picture for more info on how to override your solid state controller.
If the button in the cab is going to ground then it should work.
If the button in the cab is powered then it won't.
If you want, take a battery charger and hook it with 12v and low amp with the red/pos lead to the small terminal on the solenoid on the controller with the red wire.
Then touch the black/negative side of the charger to the other small terminal with the white wire just long enough to see if it clicks. If the solenoid dosen't click then it is probably bad. You can replace just the solenoid on the controller.
I would suggest not hooking directly to 12v as these engines used 6v glow plugs and they burn up quickly if button is held too long. I use 2 6v batteries instead of the 12v You can feed a relay to operate glow plugs between the two 6v's. I have had mine this way for 10 years and have yet to replace a glow plug. You have to hold the power to them longer (1 min in very cold weather) but it ,so far, has never failed to start. If you have a glow plug to waste hook 6v to it and hold it. It will turn cherry red. Then try 12v and see how fast it's toast.
The relay operates on 12v, 6v may give a false negative result to testing if the relay is operating.
Got to hand it to you though, this is the first time I've heard of someone putting 6v batteries in there truck for fear of burning out their GPs. Are you saying you took out your 12v batteries and added the 6v batteries. If so did you hook your GPs up in parallel and your truck electronics in series so that everything else will have 12v.
I think if I wanted to have to wait a minute to get my GPs warm I would just use 12v GPs such as the AC Delco 60g that the Chevy guys use, they fit also.
If you have a 12v glow plug that fits then that's what I would use. The older Chevy's also used a 6v glow plug. I discovered this after cooking a few with 12v. My engine is not in a Ford truck. It's in a Dodge Power wagon. I have a lot of experience fooling with the Ford's though. That[s why I did away with the controller when I put in this engine. Tried of replacing glow plugs. The controller reads voltage drop. That's why they won't stay on long enough to start the engine when one is bad. This is designed that way so you don't cook another when one goes bad. The 6v's are connected in series to equal
12v. I feed the glow plugs off the pos. terminal of the second battery. I use a 12v starter relay with isolated control circuit(meaning the 2 small terminals are power in and out to control solenoid). The isolates the 6v to the glow plug. You'll have to explain the false negative to me when testing.
Interesting how you hooked that up. I have a manual control also, but just limit the burn time.
What I mean by the false negative test is that the GP solenoid is made to click on with 12v, so 6v may not make it click. I really don't know, in fact I think it still would click, I just didn't want him to hook 6v to it and not hear a click and think it was bad if it wasn't.
Just had a thought, maybe I'm not clear on your description, but if you are calling the second battery the one with the power lead, and the first the one that is hooked to actual ground, then your GPs will have 12v if fed from the second battery since they are grounded to the engine.
The batteries are in series. POS(starter lead) lead on truck to Positive of one of the batteries. The negative of that battery is connected to positive of second battery. The negative of that battery is the ground. This is a 12v battery comprised of two 6v batteries. If you connect across both batteries it's 12v, but if you connect across the second it's only the 6v of the second battery. Everything works normally on the truck.
The only thing receiving 6v is the glow plug solenoid large terminal. The solenoid is operated by 12v through a switch.