artieb

Hi, I am having a fuel starving problem when it's really cold, 0-10 f. The truck starts fine then leans out. I replaced the fuel filter last time when the weather warmed up, and was doing fine for 2 weeks. Got a cold snap -7f. and done it again. I went through a lot of threads and understand the fuel sock in the pick-up. My line of thinking is to blow out the tank strainer, either with pressure on the lift pump's connection, or use a shop-vac on the tank's fill to loosen what may be a plugged sock. I don't know the history on the truck, IE veggie or some algae perhaps. I would drop the tank just after spring and do it right, I do not have the time at this point... The question is.... from the quick connect at the fuel pump and the sock in the tank's pick-up, is there a check valve Assembly (one way valve used to control fuel line drain back)? Warmer days are ahead, Thanks, Artie

wannadiesel

It's possible for the fuel to be waxing on the filter sock, or it may be waxing in the filter. Waxing is not the same as gelling. Fuel that's waxing will flow through the lines just fine but will form a layer of wax on a filter or screen, which then blocks the flow. Are you running white bottle Power Service or a similar product?

artieb

Wanna, Yep on hte white P/S and some 911 today... I have it in the garge, warming, overnite to help with the waxing, which was not at the filter, it's between the Q-connect at the lift pump and the tank? I thought 911 was suppose to dissolve the waxing / gelling without heating the fuel above freezing? I will see tomarrow how it acts, and then give the tank a BJ, if needed... Thanks, Artie, Again....

BC847

Your truck has a screen assmbly the encases the actual fuel pick-up. No check-valve in there that I know of. ~

wannadiesel

OK, just making sure you had your head screwed on straight and had taken the obvious steps. The 911 takes a little time to work but it should get you going.

It's also possible that you are getting an air leak only when things are really cold.

artieb

Wannadiesel, I have thought about the "cold air leak" as the temps get cold.
Would the manual primer pump lever on the FP change resistance if this was true? I was glad to see that I have a hard plastic fuel line, though. Has the ULSD caused any problems with this? Does this fuel cause problems with the line, the rubber seals at the Q-connect?
I have a 96 TDI, and the new fuel has caused my IP to leak so badly that I won't run, and need to re-gasket the IP.
I have read BC847's big line thread and didn't see any place a check valve would be. I hope the 911 & white PS works, It did run better after an hour or so, and put it in a heated garage overnight. Thanks for your support, and I'll be leaving for the BVIs on wed, and won't have a chance to check back for 2 weeks, Thanks again, Artic Artie

BearKiller

This may not have anything to do with your situation; but, I will state my theory on cold-weather air-invasion and leaks of fuel systems.

When everything is relatively new and still pliable, seals and gaskets will come and go with the temperature-related contractions and expansions of metal components, thus preventing fuel drips and air intrusion.

As time goes by and these gaskets/seals begin to become less pliable, they no longer will expand to fill the gaps created by joining metal surfaces contracting, and thus widening the gaps between them, in cold weather.

Once the weather warms back up, and the metal expands, all the various joints tighten themselves back up against the old tired seals, and the leaks disappear, until the next cold snap.

wannadiesel

I'd suspect the o-rings in the quick disconnect fittings. Probably due more to age than the new fuel.