1985 F250 6.9l diesel

200k

Injection pump and fuel lines replaced 5 or 6 years ago, maybe 10k miles ago

Driven 1-4 times per month locally for dump runs and gravel pick up etc.

Recently the truck would die at idle and was having a very hard time starting. I had to keep my foot on the accelerator to keep it running at stop signs. I picked up a fuel filter, filled it with diesel installed it and it fired right up, no problem. I let it idle for a while then I shut it off. Went out next day and it would not start.

I've since taken it to a diesel mechanic. He says it needs an injection pump(again?). That is a very profitable solution for him.

Any ideas?

 

check ur return lines

 

Sounds like a failed Lift Pump.

 

If it's a "dumper", it should be easy to inspect the fuel tank "tops" for leaky lines. Make sure there all solid, then get yourself an electric pump and bypass the mechanical one. You can always get the mechanical pump later and keep the electric for emergency's, testing etc.
If that doesn't do it, check your glow plugs.

 

Thats exactly what I had to do when I had two broken pick-up tubes and an air leak where the return line connected to the front tank

I think it's an air intrusion and probably very easy to fix and cheap compared to "just get a new pump"?!
I wouldn't take anything back to that mechanic!

I've only been learning about diesels for 3 months, though I am a shade-tree gasser mechanic and understand how each works (gas and diesel).

So, if this mechanic couldn't even take 5 minutes to check whether it was one of the big three (fuel, air, fire) then he's not a real mechanic.

All you have to do is check the glow plug circuit, including the glow plugs, with a multi-meter
Verify you are getting fuel by loosening the hard or soft lines and cranking it over to look for fuel.

If no fuel then you know it's either an obstruction in the line, air in the line, a broken pick-up tube, the lift pump or the IP.

The IP is ALWAYS the first thing most of us think of when something goes wrong and it's usually something simple..

So, first I would check for fuel at the filter head or the rubber line underneath...if getting fuel from the lift-pump then you know it's good.

then crack open a injector line, and crank it over and see if any comes out, should only be a couple spurts when cranking...


I'm going with air intrusion via the lines or a broken pick-up tube.

Is the tank full? If it has this issue at 1/2 tank or below it may be broken pick-up tube.

Being that it sits alot maybe the fuel is bad also?

I think it's something simple...

 

Did you finally get it started and drive it to the mechanic? If it still hasn't started pull the filter and see if it's full. Then we'll go from there.

 

Start with the fuel, With that amount of driving you've had some fuel in those tanks for some time. What additive are you running?

Look for fuel leaks from the tank to the filter.

Check fuel pressure at the Schroeder valve and volume.

IP and injectors can be affected by age and infrequent use. These engines like to be run daily and long. Run an additive through the fuel filter.

Return fuel system Caps and lines become brittle with age and seep as well as suck air. Good idea just to replace them.

Happy hunting.

 

glow plugs are not the issue here. don't waste your time checking them right now.

when you have the no start issue....will it eventually start with a lot of cranking? if so how does it start when it finally does? smoke? color?

do as fuzzy said, take the fuel filter off and see if it has fuel in it. if there is no fuel then you have either a leak around the filter or the lift pump is dying. would be worth it to hook up a fuel pressure gauge to the filter head and see what it is at idle. are you gaining oil level, does the oil smell like fuel? if the lift pump fails it will pump fuel straight into the crank case.

try filling up the fuel filter with some clean ATF start the truck, let idle for a few seconds then shut if off and let sit over night. restart next morning and see what it does. could also throw a heavy does of additive in the tanks.

 

Thanks for all of the tips. Here is what I did and what it's doing now-

Pulled fuel filter. It was full of fuel.
Emptied fuel out of filter and filled half way with Marvel's Mystery Oil and half fuel
Emptied rest of Marvel's Mystery into the tank, and added a jug of diesel cleaner/stabilizer as well
Turned the engine over with foot on pedal a little, nothing and then it fired and idled fine
Hopped in to drive away, pressed the throttle and RPM's would not come up, then it suddenly lunged and drove away
Drove on the freeway for about 20 minutes, it drove fine, seemed a little peppier
It has trouble going from throttle to idle, if I am driving and let off the pedal it dies, if I let the pedal back slowly it does not die, it starts right back up with some pressure on the pedal, if I don't give it throttle when I start it, it fires right up then dies, if started with some throttle or let down slowly while driving it will idle just fine
The exhaust had been pretty black for a long time, it is now not black unless I put the pedal to the floor, the exhaust is maybe a little blue if anything

So it drives great, just has trouble with the idle from speed or from first firing up

Any new suggestions with this information? Thanks for the help.

 

the filter being full kinda rules out an air leak from filter back...

maybe the throttle position sensor??

doesn't sound like an air intrusion if it has black smoke...

did you do all this with at least 3/4-full tank or how much was in tank when it was running as you described??


could the fuel filter be clogged?

does the filter have a drain??

also, I found through experience that too rich a mixture of fuel additives tends to foul and coat the glow plugs...

 

Could be your IP is gunked up, along with some old fuel. you might try something a little more potent, like seafoam, Ive used it and others have had good results with it. Fill your fuel filter with it run it for 30 or so seconds then shut it down let it set over night and the next morning fire her up drive it kike you stole it.

 

Don't know if you have done this or not but I would look over all of your fuel lines - focusing on the lift pump back to the tank - especially if your in an area where the salt the roads - The metal section of line under the frame crossmember where the motor mounts are could be the culprit. look for any wet looking spots. That line was rotted on one of my trucks when I first got it - it would be VERY hard to start - die if I got on the gas. I think the size of the metal tube was 3/8. I had to cut and bend my own which was no big deal. At the time I just got the truck so I was fixing other issues and ran it hard with diesel kleen in the fuel filter - that might have helped too - cleaning the gunk out of the ip.

good luck

 

The engine dieing when letting off the throttle is the metering rod in the pump sticking. Remove the fuel filter and drain it fill the filter with diesel clean, Howes or your favorite fuel additive.Tripple the amount that it says to add to the fuel tank. Start the engine and let run for 30 seconds, the shut it off and let it set overnite. Next morning take it for a hard run. More than likely your stalling issue wil be solved as the Diesel Clean will have freed up the metering rod withe the overnight soaking.

 

I'll try a concentrated dose of cleaner overnight. Is any brand better than the other? Seafoam was mentioned - I can get that locally for sure. I want to use the best I can get...

 

I've used Diesel Kleen in my filter

I've also used a quart of Dexron/Mercon ATF