Fuel line slippage at tank fittings

[whodat88]

I've been trying to figure why I have what feels like a fuel starvation problem about 10 minutes after startup. Talked to Eric at Vulcan and he suggested that maybe a line was sucking air. I felt around up at where the lines attach to the fuel tank module and both lines would slide around on the nipples. This seems like it could be the problem as if there were a slight leak, as the truck sat for a while the fuel pickup line leaking would allow the fuel to lose vacuum and cause an air pocket, that after startup would work it's way up to the engine. You guys that have some experience with this stuff...Is this normal? How do those lines clamp to the nipples? Since I can only feel up there I was hoping I could put additional hose clamps on them and tighten the connection.

[Zukifreek]

Maybe your tank is getting airlocked after you run a bit???

[whodat88]

I think I have found the problem to my "fuel starvation" problem, but wanted to get some opinions. These last couple of days my truck has been hesitating a lot, this after checking all the connections and finding some seemingly loose ones on the fuel supply and returns at the tank. I hadn't gotten any responses if this is normal or not, and have a call in to Eric at Vulcan. So today I fire the truck up and start into town, and it almost immediately starts to show the same symptoms, only worse. I am afraid it will die completely and pull over. Pull off the gas cap to see if maybe I am getting some vacuum issues that would restrict supply, but as soon as I start up again i get the starvation again, to the point of almost stopping completely! So I head home, and open the hood with the engine running and notice that the fuel heater that is mounted on the fuel filter housing is smoking! I feel it and it is hot to the touch, don't know how hot is hot, but it was smoking. So I pull the fuel heater relay in the PDC and it seems to cool down cause the smoking stops. I head out on the road and the hesitation is gone! So disabling the fuel heater seems to have cured my fuel problem. Question is why? Was the fuel getting to hot? I haven't pulled the codes to see, but I know Mike has mentioned that there is a code for too hot fuel. I will troubleshoot whether it's the relay or the temp sender that is faulty tomorrow, but why would a too hot heater cause this kind of problem? Also it's been very cold for here these last several days, but the heater works up to 70 deg or something I think I read, so too cold shouldn't have anything to do with this, right? Very puzzled:banghead:

[diesel4life]

It would have to be pretty darn cold to cause problems without a fuel heater. As far as the loose fittings, if your seeing wet fuel around anything, that definitely could be a problem. But any leak Ive ever had caused a hard start issue after it sat for a while. I would think if it takes that long to start acting up, you may be experiencing another problem. I would definitely pull your codes up just to see whats going on.

[whodat88]

Thanks, I am going to pull the codes shortly and check the relay. I'm thinking if the relay is stuck closed the heater would run continously, which may make the heater get hot. But the heater must run continously whenever it's cold. I'm flying blind here...for now all I know is I disabled the heater and the problem went away.

[Veridical1]

if you have stock lines they will move alittle, if its upgraded lines i would hose clamp them but make sure not to cut them, also make sure your tank vent is not clogged or it will have starving issues

[whodat88]

Thanks for the input on the lines. I thought maybe these would be a little sloppy as normal so good to get some positive reinforcement on that. Checked my fuel heater relay and it at first was open across both contacts, which is a non func, then I opened it up and moved the points and after that it tested as the manual says it should. Cycled it a bunch of times with 12 V supply and it worked everytime. Put it back in and drove the truck and within 5 minutes had the same problem. Pulled the relay and all was well. Pulled the codes and had three, the standard two: 0602 and 1693 and 0500 "no vehicle speed sensor signal", which I'll check out here in a few minutes. Just rechecked the relay and it works fine. Tomorrow I will disconnect power from the heater/temp sensor and see what happens. Don't have any idea why this is causing my truck to lose power

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As most on here know, that P0500 happens when you have wheel spin. Since it's been cold and icy here that makes sense. Just wanted to save anyone replying to the previous post mentioning it.

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Been reading on the fuel heater. I'm thinking I'll just unplug it and if everything works OK just leave it. I see a lot of guys don't use one at all on aftermarket pump/filter setups.