Help - Clogged fuel line

[bullstanky]

My transit diesel powered SIII was hard to start the other day-sputtering and coughing. I got it going, but then it stalled and wouldn't restart. The fuel filter was only 1/2 full of fuel, so I figure it's a fuel delivery issue.

I cut the supply and return lines near the tank and blew compressed air through them. Air blew through the return line both toward the engine and toward the tank. I could blow air through the supply line toward the engine, but not back toward the tank. Is there any type of valve that would prevent me from being able to blow air through the supply line back into the tank, or is that where my clog is?

To drop the tank-just unbolt the 4 bolts and drop it?

[Jeff Aronson]

Boy, I can't be of much help with diesels. However, on a gas engine, the fuel pump has a check valve that would prevent fuel from running back to the tank.

As for removing the tank, yes, it's held up by bolts. You do need to remove the sending unit that you can access from underneath the right hand seat. The cover will simply unscrew and you can then unscrew the sending unit. You'll also have to release the fuel filler hose clamp from the tank.

Good luck,

Jeff

[leafsprung]

Pull your pickup tube and check it before dropping the tank. You do not need to remve the sender to drop the tank, just unhook the electrical connector . . . You will need to disconnect the filler neck and breather tube behind the seat if its a conventional civilian tank arrangement.

[SafeAirOne]

Hmm...maybe I'm missing something here or my 109 is different than everyone elses. Unless you're in it for the experience, dropping the tank won't do you any good, as far as I can tell. I've got a SIII 109SW. If yours is like mine, you'll be able to access the fuel pickup tube/sender unit from inside the Rover by unscrewing the 2 screws and removing the access panel in the rear tub floor. Disconnect the 2 wires on top of the sender (note which one goes where). Slip the fuel hose off the elbow and knock the cam locking ring anti-clockwise until it is loose and remove the sender. Clean the VERY fine mesh screen on the end of the fuel uplift tube. Reassembly is reverse of disassembly. Wash your hands 5 or 6 times and enjoy the smell of diesel for the next few days!

PS--If yours used to be a 2.6, 6-cylinder, then there's also an electric fuel pump mounted on the right-hand chassis rail below the door t-post that may or may not have an internal filter that might or might not be clogged. (I don't know much about the pump--I electrically disconnected my pump after installing the 2.5 diesel and fuel still flows through mine without issue).

[bullstanky]

Hmm...maybe I'm missing something here or my 109 is different than everyone elses. Unless you're in it for the experience, dropping the tank won't do you any good, as far as I can tell. I've got a SIII 109SW. If yours is like mine, you'll be able to access the fuel pickup tube/sender unit from inside the Rover by unscrewing the 2 screws and removing the access panel in the rear tub.

Wow-thanks for the info. I think you just saved me a ton of time and effort!!

[leafsprung]

Wow-thanks for the info. I think you just saved me a ton of time and effort!!

I wouldn't get so excited . . .yet

Hmm...maybe I'm missing something here or my 109 is different than everyone elses. Unless you're in it for the experience, dropping the tank won't do you any good, as far as I can tell. I've got a SIII 109SW. If yours is like mine, you'll be able to access the fuel pickup tube/sender unit from inside the Rover by unscrewing the 2 screws and removing the access panel in the rear tub floor.

Drpping the tank wont help too much with the diagnosis as I mentioned. However, if the pickup tube is clogged, the junk its clogged with is coming out of the tank. If its fuel residue, gel, algae, or other deposit, its probably a good idea to boil it. If its rust, debris or sediment, its probably a good idea to boil it and recoat it. It either case, clearing the pickup tube is likely a temporary measure. Inspect the inside of the tank and the obstruction closely before simply blowing out the pickup tube and re-installing.

[SafeAirOne]

Drpping the tank wont help too much with the diagnosis as I mentioned. However, if the pickup tube is clogged, the junk its clogged with is coming out of the tank. If its fuel residue, gel, algae, or other deposit, its probably a good idea to boil it...

Good point. Mine was just fine sediment from some sandstorms that worked its way into the fuel tank. I ended up just putting 5 gallons of diesel in the tank, sloshed it around, then jacked up the front end. After 2 hours, once the junk settled to the bottom rear of the tank, I just stuck a tube through the sender hole and started a siphon, vacuuming all the crap from the bottom of the tank.

[bullstanky]

I wouldn't get so excited . . .yet

So, it turns out I have a sump style fuel pump in the tank at then end of the pickup tube, and my stalling was caused by a loose electrical connection to the pump. I took off the access plate, took out the sender and pump, and did my best to clear out the mesh screen on the end of the sump. When I put it all back together, the pump worked, repressurized the fuel system, and it started right up. There was little or no sediment in the tank or the filters, so I figured I was good to go.

I ran the engine for a good 20 minutes at idle with no issues. I then loaded up the wife and the dog and off we went. But then, a mile or so down the road, she started to slowly die and then stopped. I was able to start back up and get going again, but then the same thing. When I got her back in the driveway, I found that idling was not a problem, but as I increased rpm slowly, after a while, she'd slowly start to die of fuel starvation. Is it time for a new pump - how does one pressure test an electrical fuel pump to ensure proper operating pressure? Could there be a clog in the tank vent that is causing a vacuum build up?

[SafeAirOne]

What year is your 109 & what engine? Unusual to see an in-tank pump. Is it one of these pumps?



As you know, your fuel pump is pumping, but as it pumps, it begins to build a vaccuum. When the vaccuum is greater than whet the pump can deliver to meet engine demand, the engine dies. The faster the engine revs, the more demand for fuel.

If you are certain that all filters are clean and the sediment screen on the pickup is clean and there are no dented/crushed/pinched fuel lines, then you should probably move on to the vent system.

If your 109 has emission control stuff, make sure the lines to the charcoal canister and canister are free of obstructions. If you don't have emissions crap, make sure your fuel cap vent is open. There was a fuel cap thread lately that probably has more detail. (I don't have emissions junk on my 73).

Either way, I'd remove (if practical) the fuel cap and drive around a bit and see if it still shuts down on you. If it doesn't, the vent or emissions stuff is suspect. If it still shuts down on you, the fuel supply lines/system is suspect.

[SafeAirOne]

Previous thread about fuel caps and charcoal canisters:

http://www.roversnorth.com/forums/showthread.php?t=5598

[bullstanky]

What year is your 109 & what engine? Unusual to see an in-tank pump. Is it one of these pumps?





If you are certain that all filters are clean and the sediment screen on the pickup is clean and there are no dented/crushed/pinched fuel lines, then you should probably move on to the vent system.

Yep, that's the pump exactly. I don't know the year (it's an SIII) and the engine is a ford transit diesel transplant.

I pulled the pump the other day and the pickup screen looked fairly clean. Is there a way to remove the mesh screen from the body of the pump for further cleaning?

I think I remember a fairly solid vacuum buildup (i.e. I hear the air get sucked in when I remove the gas cap), so running without the cap is my first move.

If that doesn't solve the problem, I think I'll pressure test the fuel pump, but when I bled the injection pump after re-installing the fuel pump, it seemed like there was plenty of pressure. My other thought is that clogged injectors could be limiting fuel flow from the other end, or this could be happening in combination to vacuum issues.

[SafeAirOne]

I think I remember a fairly solid vacuum buildup (i.e. I hear the air get sucked in when I remove the gas cap), so running without the cap is my first move.

If this is the case, you've got a clogged tank vent. Check for emissions stuff obstruction/obstructed fuel cap vent, depending on your particular setup.