Newbie needs help with his first diesel (Please)

[Mad Maxine]

Just started my first foray into the wonderful world of diesel motoring. Many thanks to Rudolf Diesel's mother for having such a bright and inquisitive son to develop an internal combustion engine which requires no repetitive electrical ignition. But, I digress--

Just got an '86 F-250 w/ a 6.9 Navistar. My daughter has named her Mad Maxine. She's ugly. Here is her picture:

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She's my first diesel, but I am pretty handy with a wrench, and have worked on many a gasser.

Here's what's happening:
Truck has been running fine. Changed the fuel filter and valve cover gaskets over the past weekend. Started her up, and she idled fine. Took her around the block, no problems. Decided to drive her to work yesterday, and all was well for the first 15 miles or so, then she lost power and died. I coasted into a parking lot, and tried to re-start, but no luck. Being a (new-to-me) truck, I wondered if maybe the fuel gauge was wrong, and I had run out of diesel. I switched to the rear tank, and hit the starter, and after a few cranks, she came back to life. YAY! Clearly, I had just run out of fuel. I drove directly to the filling station, and filled up. Cranked her back up, and drove the last 5 miles to work. Fast-forward to 5:00. Jump in and crank her over; she starts up, but seems to idle a little rough. I back out and drive out of the lot, and the engine seems to smooth out. Drive 1/4 mile to the first stop light, and she slowly drops idle speed and dies. After a few cranks, she starts back up. Drive on down the highway @ 55/60 mph, and again, in about a mile or so, she loses power and dies. Coast to the side. After waiting for several minutes, she cranks up again. Get back on the road. Another 1/2 mile, same thing. She drops power and quits. Now she wont start at all. 20-mile tow home. ouch.
I've looked around, and I've seen some troubleshooting advice on this engine, but it doesn't seem to fit my profile. She (did) crank and start, and would run more than a couple of seconds.
What would cause the engine to run for a little while, lose power, and then quit? I suspect I did something wrong when I changed the filter, because it ran fine before that. I drove it 2 hours home from where I bought it last week. I filled the filter with diesel and a little Diesel Kleen, and it cranked right over. I'm not really sure where to start.
Sorry to be so long-winded.
Any advice would be appreciated.
Thanks much.
Craig

 

[laserjock]

Welcome! Put your truck's info in your signature. It will save a lot of questions when you ask for advice.

If your tanks are full, check your lift pump. Is it mechanical or electric? If it's not been converted, its mechanical and may be the culprit. Sounds like a supply problem to me. How many miles on the injection pump and injectors?

 

[BDCarrillo]

Without any other info, I would strongly suspect the lift pump and/or showerheads. If it acts up on a full tank (ie, temporarily ruling out the shower head), consider swapping the lift pump. If it doesn't have an original IH or Ford stamp, change it ASAP! Delphi, spectre, and airtex are dubious pumps... Carter is the way to go.

Check the water separator on the firewall, they can be a very bad source of air intrusion.

If you didn't pre-fill the fuel filter, it's likely full of air and starving the IP.


Laserjock beat me to the punch... Stupid slow phone keyboard lol

 

[Mad Maxine]

Thanks much. I'll go figure out how to add info on my signature.
Injectors were replaced last year, I don't know about the lift pump and IP.
The engine has 240k miles on it.

 

[Mad Maxine]

Without any other info, I would strongly suspect the lift pump and/or showerheads. If it acts up on a full tank (ie, temporarily ruling out the shower head), consider swapping the lift pump. If it doesn't have an original IH or Ford stamp, change it ASAP! Delphi, spectre, and airtex are dubious pumps... Carter is the way to go.

Check the water separator on the firewall, they can be a very bad source of air intrusion.

If you didn't pre-fill the fuel filter, it's likely full of air and starving the IP.


Laserjock beat me to the punch... Stupid slow phone keyboard lol

Thanks much. I did fill the filter with diesel and some Diesel Kleen, and it cranked right up.
Forgive my ignorance, but what's the "showerhead"? Screen pick-up in the tank?

 

[BDCarrillo]

Thanks much. I did fill the filter with diesel and some Diesel Kleen, and it cranked right up.
Forgive my ignorance, but what's the "showerhead"? Screen pick-up in the tank?

Correct, the showerhead is the in-tank pickup & screen assembly. They're notorious for falling off and not picking up the last 1/4 tank of fuel.

 

[Waystro]

Awesome another Texas Member.

I was thinking man I've seen that truck. Some where.
If you need any parts I might have some stuff of use just ask and I'll see if I have it.

 

[Waystro]

To fill out a Sig go to settings and there will be a drop down on the left that that says edit Sig click there and your good to go

 

[Mad Maxine]

I was thinking man I've seen that truck. Some where.

I bought it from a guy in Oakalla, Texas. Truck spent its entire life in Oakalla.
Thanks much!

 

[Waystro]

If it had been a ex cab I would have probably picked it up.
I have anough of a project has it is Tho

 

[junk]

What do you guys think about IP heat soak? or is that more of a won't start warm issue?

Definitely sounds like supply.

 

[gandalf]

Hi Craig. Welcome to the best IDI site on your computer. There is more collective knowledge here about these wonderful old trucks than you will find at most dealers.

You asked about the shower head. It is indeed located in the fuel tank, one in each tank. It is the screened pickup on the fuel line. It is also one of the problem points with the fuel system. The shower heads eventually fall off the tubes they are mounted on. When that happens the bottom quarter of the tank is not usable. The tube is not long enough to reach that fuel. You gage will read 1/4 tank, but you are effectively out of fuel.

There is a fix. The shower head can be replaced with a short length of diesel rated rubber hose, extending to the bottom of the tank. For a visual of this, take a look at my thread, started on 30 May I believe. There are some pictures, which helps most of us. We are pretty much all visually oriented people.

See the thread: Fuel tank pickup

 

[Mad Maxine]

Check the water separator on the firewall, they can be a very bad source of air intrusion.

What do I need to look for?
I pulled on the ring and nothing came out.
I've read that these water separators can be problematic. Is there a fix/replacement for them?

 

[Mad Maxine]

You know, when I was thinking about buying this old truck, and knowing nothing about diesels except that they don't have an ignition system to deal with, I thought---man, they've got to be a lot simpler to troubleshoot when you take an ignition system out of the equation. What I failed to realize is that what it lacks in ignition system it makes up for in fuel system!!
Oh well. Part of the reason I got it was to learn about diesels.
I'm learning, alright.

 

[gandalf]

What do I need to look for?
I pulled on the ring and nothing came out.
I've read that these water separators can be problematic. Is there a fix/replacement for them?

Yes, the water seperator on those older IDI truck can be problematic. You seem to have found it---on the driver's side fender near the firewall, with a pull ring on top. The problem is that when you pull the ring to drain any water, the thing does not properly re-seat itself, and allows air into the fuel system. That is not a good thing.

A temporary fix is to simply eliminate it from the system. Don't pull it out, just re-route a line around it. Take it out of the equation.