Indeed. I have a propane tube heater we may have to put into service....

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Rob M
Norwich, VT USA
1980 240D Euro delivery 4 speed manual silver/blue
~160K miles

Is there a lift pump in that tank had a car one time where the rubber tube that holds the fuel pump on had a split in it that drove me nuts

Added this thread to ShopForum > Do It Yourself Links & Resources > DIY Links by Parts Category
Fuel Delivery:
Diesel Fuel Delivery:




This may save another owner from massive frustration.

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This car doesn't have a pump at the tank, but he found the problem, it was a small crack in a hose.

I have posted this elsewhere on a thread I started months ago. I have an 84 TD and have the same air in the fuel problem but I have replaced everything between the tank and the fuel pump. I have replace the rubber lines at least twice and checked for interior condition etc. I even used the expensive nitril stuff. I replaced the metallic line even though I could not find a leak in the original one. My fuel tank is dented right at the fuel outlet and I am wondering if any internal damage could cause a leak? What about the vent lines to the expansion tank? My car can run all day as long as I stop for periods of at least 5 minutes but continuous driving results is sever power starving and usually stalling. When the car stops the fuel filter is dry and some times, even vigorous pumping with the new primer pump draws nothing. Waiting for 5 to 10 minutes allows fuel to be drawn again. I have put a hole in the fuel cap to make sure it is not vacuum lock. The problem can happen with a full tank or an almost empty one. I have checked the vent valve and it opens at just the factory spec values. The strainer has been checked several times. The tank was steam cleaned. All lines blown out. Cracks in overflow tank fixed and lines to it replaced but I did not replace the rubber between the tank and the hard lines to the expansion tank thinking that air could not get in there and it will require removing the tank a third time.

Could internal damage in the tank allow air to get into the " false bottom" that feeds the supply to the fuel pump? The car runs fine with a tank on the roof. I have replaced the rubber lines from the tank to the fuel pump 3 times. Is it possible that 1/4" line will just not seal and that I need to get the right metric size? I am using worm clamps and they seem to make a good physical connection that can not be twisted.

I have spent something like 40 hours trying to fix this and had to buy a new car because I could not depend on the good old TD. I love that car and want to fix her. What else can I try?

Test fuel volume from the return hose, use a gallon jug.
Ten seconds engine cranking.
Post the results for further diagnosis.

I measured the output from the return line both with the FIP control pulled to stop to prevent enging from starting so I could measure the output at cranking speed. Also measured it with the engine sort of running with the FIP not in stop mode. Output in ten seconds was a paltry 70 ml at cranking speed and twice that with the engine sort of running 140 ml.

I also replaced the two lines at the primary filter with 1/4" instead of 5/16". Although these lines have been replaced a few times, they did show some cracks at the ends after the hose clamps. Is it possible that 5/16" rubber doesn't compress properly and provide a tight seal? I have to drive 2 hours to get to a place that might have metric sized hose.

I also removed the new primer pump and tested it for leaks. It does not leak at all. I them made a stubby wrench to make sure it was tightened very well.

I want to repeat that when the car failed the last couple of times, there was no fuel in the primary filter at all and the priming pump did not seem to pull any in until I waited for at least 5 minutes. I had removed the tank cap so it was not vacuum lock. The tank has a rather large dent in the bottom near the output line. Is there any possibility that internal damage might allow air from the expansion tank to get into the the supply instead of fuel through the strainer? The strainer was removed quite recently and was not fouled. I am goint to drain it again and look for a clogged strainer but I really want to avoid removing the tank. It is a ***** on the TD. The rubber lines at the fuel tank tha connect to the hard lines going to the expansion tank have not been replaced. The ones at the expansion tank have been. Can air be getting into the system there? I have no idea what the lines do once they enter the tank. The tank needs to be removed to replace these so I hope that is not needed.

I had a primary filter that had a crack in it along the injection mold line. I did not leak, and the car idled fine. It was running down the road that the issue of fuel starvation made itself known. It was a Purolator filter bought at Pep Boys, and it lasted about a week.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

I thought of that too and tested it with about 30 psi and it did not leak. Maybe it only leaks once it warms up and leaks vacuum but that is a little hard to believe. I think I have a spare to try. I definitely have some generic clear plastic filters. Any reason one of those won't work?

Need to restate that I could not draw any fuel with the primer pump making me think that the problem is more likely at the tank end. If it were in the filter I would expect to hear a hissing as I tried priming.

I had also replaced the primary pump with one from a parts car. No idea if it was any better than the one I replaced but that would be quite a coincidence if both were bad. The parts car was a sedan, however and I think that the lower tank of the TD might require a perfect pump and totally leak free system whereas the sedan provides a little gravity pressure to make it less critical?

Does my output level sound really low? Should I replace the primary pump?

Maybe the filter was leaking at the mold line. Maybe the tighter fuel line would fix it. It is a part bought from an auto parts store as that was all that was available when I was having biodiesel loosend crud filling up the filters. I think I have an old Merz original that is not clogged and I can try. Will look at the mold line more carefully.

Is there any point in putting a pusher pump at the tank? That might make the whole system a lot less critical?

What happens when you remove the filler cap?

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Maybe one of the rubber fuel lines is collapsing internally?

I've also heard of a case (in a non MB gasser) where debris in the metal line under the car would shift and cause a blockage. Stop the flow by shutting off the engine and the debris would settle and allow fuel flow once again. Perhaps you have somethinhg similar.. or some big chunks of fungus that float around and get sucked up against the filter screen.

Perhaps temporarily eliminate the hard line under the car by running a parallel rubber line all the way to the back? If that doesn't fix it, maybe run temp rubber lines further into a separate tank in the back? If that doesn't fix it, then the problem is somewhere under the hood.

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Where is or are the DIY Links by Parts Category .....
I tried the "DIY Links" Tab for the site but did not find this thread relocated.
:EDIT whunter: Corrected post# 18 and added a link to it.
Fast navigation Do It Yourself Links
Fast navigation Do It Yourself Links

I did not get notification of new posts so I had no idea there were additional suggestions.

Removing the cap does nothing. I have run without it and had the same problem. I have drilled a small hole in the cap to prevent vacuum lock although the vent valve works fine. Might be some problems with mush ylines between the tank and the expansion tank so I drilled the hole in the cap.

I checked the strainer at the same time that I installed a completely new hard fuel line. The old one looked fine when Icut it in half and ran a fish tape through it. No crud came out. Strainer was quite clean. No fungus.

Running with a tank on the roof it runs great. Ihad posted the results of a crank speed fuel output test at the request of one reader but never heard back whether it suggests that the fuel pump is bad. I had replaced it with one from my parts car early on. At cranking speed with the FIP shut off, it puts out 70 ml in 10 seconds, 140 if the car is allowed to sort of run for 10 seconds while cranking.

I doubt that rubber lines are collapsing because they are all new. I thought of the idea of crud building up at a high spot and falling down in the 5 minute rest period that restores operation but there was no crud in the thank, the lines or the filter.

I also put a suction pump on the line right after the primary filter with a 1 quart trap bottle to watch the flow while I pulled real hard on the pump. I could produce a fast flow without bubbles or any problems so nothing is preventing flow or letting in air until whatever happens when the problem occurs. I had replaced the two lines at the primary filter before doing this so maybe the fact that they were 5/16" instead of 1/4" was the problem all along and it may be solved. Will not know until I drive it 100 miles or so but I still have no confidence that this was the problem.

Again, does anyone think that the expansion tank and the rubber lines to it could be the problem? I don't understand how the expansion tank works. The pcitures in the shop manual do not show where the lines go in the fuel tank or the expansion tank. Can air get into the fuel from the fuel tank to the pump via the expansion tank?