6.9 quit

[quickster]

Check your filter. Like I said in my other post, my truck would run for 10 minutes then start coughing and die. Change out the filter and it would do it again. When you start going up and down hills you mix all the chit in the tank. If you don't want to take a chanc driving it, but want to see if the fuel is contaminated, bring along a 5 gal plastic bucket, preferably white. Spackle bucket. Bring some clear hose to siphon some fuel. Get the hose in far enough to get to thebottom and get a couple gal out . Bring it home and let it sit overnight. If the bottom of thebucket has a layer of silt then you know the answer.
If you could rig something up to the lift pump where you disconnect the fuelline from the tanks and run it off a gallon container. Just to get home, but I can just see it on the internet.....

 

[gnathv]

Try to start it, if it doesn’t start check fuel pressure at schrader valve on filter head. If you have fuel pressure check for fuel out of injector pump. If you have no or low fuel pressure, (should get 1/3 of pint in about 10 seconds cranking) connect fuel line to inlet of fuel pump and stick the other end in a can of fuel. If it’s tanks or clogged lines it should start and you can get it home.

 

[Brian VT]

Mechanic says he filtered some fuel and no crap in it so, knock on wood, the tank(s) and pickup(s) are clean. He says it runs fine for more than 1/2 hour there (at idle). So now I'm thinking maybe plugged fuel tank vent? Do these vent through the filler cap? Wouldn't that be a nice easy fix.

 

[gandalf]

I'm not sure whether our tanks vent through the filler cap. If all else fails, call your parts store. They'll know which cap you should use, and whether it vents.

What I do know is that there is a vent built into the top of the tank. It's not much of a vent, but it is a vent. It's given some members lots of trouble. Look in the Tech Article section (top of this part of the forum) for vent articles.

Just for S&Gs I'll attach a picture of my rear tank. The white thing in the middle of the tank, with a single hose attached, is a vent. There is a similar vent on the front tank.

 

[Brian VT]

Thanks. Would you happen to know where the vent hoses end up so I can check that they're functioning?
Edit: Sorry. I should check the Tech Article before bothering you. Will do.

 

[gandalf]

The hose I showed, for the rear tank, goes toward the driver's side. You can see it clipped to the crossmember at the very bottom of the picture. It doesn't go far, so once you find a part of it, just follow it a couple of feet. At least that's the way it is on my truck.

 

[Farmer Rock]

Did you check your lift pump? Make sure you are getting 4-6 psi at the Schrader valve. Just because it idled don't mean malarkey.
It could just be stalling under load.
Been there plenty of times .

Rock

 

[Brian VT]

It's at the mechanic's now so I can't check. He did say that the lift pump looks new.
It drove mostly fine, even under acceleration, until it quit.
There were a few moments where it seemed to "clean up" and accelerate while I was at steady throttle. Kinda like when a 2-stroke hits the power band.
I've never had a diesel but I'm thinking maybe it was slightly lean/starved for fuel during those moments? And later it just quit like it ran out of fuel. I had it towed and it started and ran fine for the mechanic. That's what got me thinking that the tank vent might be holding fuel back. I wish I had thought to loosen the filler cap and see if it started. That would have given me a clue.

 

[Farmer Rock]

It's definitely gonna be process of elimination either way, but I will suggest that you make sure the mechanic actually tests the lift pump even though it may look new.
The IP will usually pump "some" fuel on it's own, but it's just not consistent, hence the reason for a separate lift pump.
It's very unlikely that both tanks have clogged vents, but weirder things have happened.



Rock

 

[Brian VT]

I had him bypass the tank switch valve and just run from one tank because I suspected the switch valve was the source of the air leak. That did seem to solve the air leak. So it could be the one tank with a clogged vent. Maybe I should have him switch which tank it's drawing from.

 

[Big Bart]

It's at the mechanic's now so I can't check. He did say that the lift pump looks new.
It drove mostly fine, even under acceleration, until it quit.
There were a few moments where it seemed to "clean up" and accelerate while I was at steady throttle. Kinda like when a 2-stroke hits the power band.
I've never had a diesel but I'm thinking maybe it was slightly lean/starved for fuel during those moments? And later it just quit like it ran out of fuel. I had it towed and it started and ran fine for the mechanic. That's what got me thinking that the tank vent might be holding fuel back. I wish I had thought to loosen the filler cap and see if it started. That would have given me a clue.

Some thoughts -

1) When these trucks surge or as some say buck, it is usually fuel starvation.
2) Rule #1 on this site, don’t assume any part new or reman is working or will stay working. Story after story after story on this site. It’s sad but it is true. So as Rock said don’t assume the lift pump is good because it is new. Test it and confirm It works. Also the PO may have been trying to fix this issue and put a lift pump in to see if that would fix it.
3) When you get it to run make some mental notes.
a) Which tank it is now working on?
b) Does it happen below a 1/3 of a tank or less. (Your shower head may have fallen off and you can no longer run say at 1/4-1/8 of a tank without sucking in air.)
c) Add 3 gallons of diesel, does it go away, perhaps your fuel sending unit or gauge is not working.
d) As you mentioned try the other tank.
e) But looking in the tank will answer a lot of questions.
f) Many take a 5 gallon gas can, hook to the lift pump, put the gas can in the bed and test drive. Confirms it the fuel lines, selector valve, or something in the tanks is the cause.
4) Did he bypass both the inlet and return lines or just one. Take a look and confirm both. If just one line is bypassed it could be your issue.

You also could have a fuel line letting in air. If you do have a new lift pump make sure the rubber hose from the fuel line to the lift pump is new (PO did not use the old hose.) and clamped properly on each end.

It can also be at the IP. if your IP solenoid looses power or goes bad it will cut off your fuel and shut off the engine. So a bad ignition switch (And a key chain full of keys swinging), broken wire, or failing solenoid could also cause a shut off. But it would have likely been more it died than surging/bucking and slowly dying.

Let us know what you find out.

 

[Brian VT]

I filled both tanks when I got the truck because the fuel gauge seems whacked out.
The ignition switch/IP solenoid is something that caught my attention. While trying to get it restarted I did notice what seemed like a sparking sound from the key area when I turned the key from the off position and back. Hmmm...
No heavy key chain. Just the 2 keys. Both times it died suddenly. No surging or slowly dying.

 

[Big Bart]

Some thoughts -

1) The ignition switch is down by the brake pedal on the steering column. But maybe it is sparking so loud the sound traveled up the steering column. But many on this site are facing worn cylinder locks, push rods, and ignition switches. Some have suffered from the ignition switch staying in start mode after letting loose of the key. If the ign switch (Or the lock or rod) is not working, its easy to determine, leave the key in the on position when it won’t start. Use a meter or test light to test for +12v at the IP solenoid connector. (The cold advance is next to it so test the right one.). FYI you can generally hear and feel the IP solenoid move to on when the key is moved to on. Also make sure the solenoid continues to get power when you turn to start.

2) Since you are a new owner two things about filling the tanks. This style of Ford truck has issues with filling up the fuel tanks. (I think you might have started a thread on this. Sorry if that was you.) For me I have to hold the pump up during the fill or it just clicks off each half or whole gallon. So did you get at least 5 gallons in each tank? (Or did it just keep clicking off and you figured they were full.) Often the shower head comes off so you cannot run the tank to empty. My original sending units like most other members have died. So I set my trip odometer and fill each tank every 120 miles. So just make sure you were not fooled by this issue and your tank is at least half full.

3) But you could have junk in the fuel tanks and now perhaps in the lines. This could also foul up your tank selector valve. So taking out the tanks and cleaning or replacing them would fix that. But you can also put in new sending units and actually see when to fill your tanks. Then blow out the lines from the rubber hose going to the lift pump. Not suggesting 150psi, rather more like 10-15psi.

This is the hardest part of buying a old IDI, the prior owner does not give you all the history. Often sell these due to issues they may not have disclosed. So don’t get too worked up or bummed out. You will get your fuel delivery issues resolved and that is 30% of your potential challenges fixed for some time.

 

[Brian VT]

Well I picked it up and made it all the way home. ;-) I didn't take the long way like last time, though.

Mechanic said he removed the injectors (I believe they're new. Not sure what brand.) and said they weren't in tight and there were old crush washers in there. He listed that he replaced the copper crush washers and O-rings and "plastic cup" and fuel line for fuel return. I don't know if the "plastic cup" has to do with the injectors or the fuel return.
And I don't know if any of that has anything to do with it quitting on me and having to get towed twice.

 

[Big Bart]

Likely he did a new return line kit. Plastic cup goes on top of the injector and collects the extra fuel and sends it down the rubber lines.

Also good he caught the injectors we’re not installed properly.

So now you can focus on the IP to the fuel tanks for lack of fuel problems.