1985 f250 6.9idi
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1985 f250 6.9idi
I just purchased a 1985 F250 6.9idi 4 speed 4x4, it's got 55000 miles. I was wondering what all I should watch out for since this is my first idi. Any wise words would be greatly appreciated
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From: Angier, NC
Welcome to FTE
Is that 155K and not 55K? Not that 155 is a bad think on a diesel.
I had 230K on a GM 6.2 and at 100K I added a Gail Banks turbo kit.
I will let the diesel guys answer but I dont see anything you really need to look out for other than do service when it is due.
Dave -----
Is that 155K and not 55K? Not that 155 is a bad think on a diesel.
I had 230K on a GM 6.2 and at 100K I added a Gail Banks turbo kit.
I will let the diesel guys answer but I dont see anything you really need to look out for other than do service when it is due.
Dave -----
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From: Virginia
The early diesels like yours had a fuel/water separator on the firewall that always gave problems, letting air into the fuel. Even with only 55,000 miles, yours has probably already been deleted but if it hasn't, bypass it.
You most likely have the early glow plug controller. But maybe they also upgraded it. If you have the old controller system, it will be screwed into the back of the engine. The newer version mounts on the top rear of the engine. The original units are prone to sticking on and burning out the glowplugs. Do some research, maybe the replacement screw controllers are ok, I do not know. Or you could convert to a manual pushbutton switch for the glowplugs, making it pretty much bullet proof as far as failures.
You most likely have the early glow plug controller. But maybe they also upgraded it. If you have the old controller system, it will be screwed into the back of the engine. The newer version mounts on the top rear of the engine. The original units are prone to sticking on and burning out the glowplugs. Do some research, maybe the replacement screw controllers are ok, I do not know. Or you could convert to a manual pushbutton switch for the glowplugs, making it pretty much bullet proof as far as failures.
Logistics Pro
Joined: Jun 2017
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From: Edmond, OK
An 85 should have the older style glow plugs. The controller is in the back of the driver's side head. If you turn the key to RUN the Wait to Start light on the dash will cycle and you'll hear the glow plugs click ON/OFF a few times (about 12-20 seconds). Then it should start.
If your glow plugs don't work properly don't bother replacing the controller. I tried that and the new controller only lasted a few months. You'd want to follow one of our threads to install a pushbutton for the glow plugs. Also, make sure you only use Motorcraft glow plugs if they need replaced. Others are known to swell and the tips break off in the head.
x2 on bypassing the OE water separator on the firewall. I made the mistake of pulling the ring to drain the water and caused killer air intrusion when I first bought the truck.
If your glow plugs don't work properly don't bother replacing the controller. I tried that and the new controller only lasted a few months. You'd want to follow one of our threads to install a pushbutton for the glow plugs. Also, make sure you only use Motorcraft glow plugs if they need replaced. Others are known to swell and the tips break off in the head.
x2 on bypassing the OE water separator on the firewall. I made the mistake of pulling the ring to drain the water and caused killer air intrusion when I first bought the truck.
Last edited by Olds64; Today at 06:48 AM.
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An 85 should have the older style glow plugs. The controller is in the back of the driver's side head. If you turn the key to RUN the Wait to Start light on the dash will cycle and you'll hear the glow plugs click ON/OFF a few times (about 12-20 seconds). Then it should start.
If your glow plugs don't work properly don't bother replacing the controller. I tried that and the new controller only lasted a few months. You'd want to follow one of our threads to install a pushbutton for the glow plugs. Also, make sure you only use Motorcrafts glow plugs if they need replaced. Others are known to swell and the tips break off in the head.
x2 on bypassing the OE water separator on the firewall. I made the mistake of pulling the ring to drain the water and caused killer air intrusion when I first bought the truck.
If your glow plugs don't work properly don't bother replacing the controller. I tried that and the new controller only lasted a few months. You'd want to follow one of our threads to install a pushbutton for the glow plugs. Also, make sure you only use Motorcrafts glow plugs if they need replaced. Others are known to swell and the tips break off in the head.
x2 on bypassing the OE water separator on the firewall. I made the mistake of pulling the ring to drain the water and caused killer air intrusion when I first bought the truck.
I also use a manual momentary button to operate the glow plug relay. And the water separator has been bypassed as well.
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I've heard the same thing about the glow plug tips and just leaving them alone once they start swelling definitely sounds like the safer move compared to forcing them out. The manual glow plug button setup seems to be pretty popular on these older IDIs too.
Have you been running that setup long term without any issues?
Have you been running that setup long term without any issues?
Logistics Pro
Joined: Jun 2017
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From: Edmond, OK
I've been running the manual pushbutton for years with hardly a hiccup. I recently had to replace my glow plugs. 15 out of 16 Motorcrafts that I had tested bad.
Here's a hi speed glow plug push button kit. Of course, you can do it cheaper yourself (just run switched 12V to your glow plug relay). I actually have to think about getting this kit. I like the heavy duty harness. 🤔 I've ordered from CDD before. A+ on customer service and parts.
https://classicdieseldesigns.com/pro...conversion-kit
I suggest reading this thread on counterfeit glow plugs. It has some good videos too.
https://www.ford-trucks.com/forums/1...zd-28-a-3.html
Here's a hi speed glow plug push button kit. Of course, you can do it cheaper yourself (just run switched 12V to your glow plug relay). I actually have to think about getting this kit. I like the heavy duty harness. 🤔 I've ordered from CDD before. A+ on customer service and parts.
https://classicdieseldesigns.com/pro...conversion-kit
I suggest reading this thread on counterfeit glow plugs. It has some good videos too.
https://www.ford-trucks.com/forums/1...zd-28-a-3.html
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Lead Driver
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I've been on the manual button for decades. In fact I wore out my first momentary button. It was cheap junk. I replaced it with a better one that looks more robust. Been installed for 4 or 5 years now. The first one came apart and wouldn't make contact. Not like the contacts wore out. It was the mechanism that failed. Look for a well made momentary button and you are good. I also have a splice in the wire that I can undo a wire nut and touch the positive battery terminal with it. That came in handy the day that the momentary button failed.
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From: Virginia
One way to get a swollen glowplug out is to loosen it all the way, of course it won't come out but just leave it. Then crank the engine. I have never tried it, I have all good ones in it now, but I have heard it works, just a little hard on the hood insulation.
One thing I never liked about the controller, 1 bad plug or a couple corroded connections on a few glowplugs, it will not glow enough to start the engine. You are dead in the water. I have run the manual button for years, had 3 glowplugs bad during one winter, and I was still able to start the engine with the manual button. It wasn't too happy about it, but it did start. I did not have time to fix it right away, we had a big snow storm that year.
One thing I never liked about the controller, 1 bad plug or a couple corroded connections on a few glowplugs, it will not glow enough to start the engine. You are dead in the water. I have run the manual button for years, had 3 glowplugs bad during one winter, and I was still able to start the engine with the manual button. It wasn't too happy about it, but it did start. I did not have time to fix it right away, we had a big snow storm that year.
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