Fuel problem has everyone around here stumped.. Please Help!

[idiabuse]

Wow such a simple fix and nobody is brave enough to do it. Delivery is all the engine wants, Yea you have to take things apart to find the source of blockage.
Having the OEM fuel system, yea makes you have to jump a lot of hoops to get it right. I ditched my entire fuel lines and fittings for A/N fittings and 5/8 to 1/2 to 3/8 fuel lines all flow.
Never have delivery issues like I used to, reading this thread is like a bad nightmare.
Good note though, My trucks runs better on WMO than clean diesel, I must say! Less leaks, No air in the lines, starts faster when hot, Much Much CHEAPER to operate my truck!

My fuel system was made back when I has having these same issues the OP has posted.
I finally had it one day and used as much left over parts from my drag cars to make my
truck drive me around instead of turning me into a union slave.

Javier

 

[mr_smith]

Well, I listened to ocelotl's advice and started following what he advised me to do.

When I unhooked the inlet to the lift pump and rigged up a hose to draw fuel out of a container, the truck ran fine. Hot, cold, high rpm, idle... everything. Put about 4 gallons of fuel through it and it never acted the slightest bit off. Ran it for about 20 mins to 1/2 hour like that.

So, if I understand correctly, that means my problem is somewhere before the lift pump. Is this correct?

I am waiting to hear from you guys about what you suggest for my next course of action.

My thought is to remove the sending unit, blow it out with air and replace with the same unit. Then run all rubber fuel line from the tank to the lift pump. I plan to bypass the tank selection valve/switch. The water separator is already bypassed.

Is this what I should do? I could use any help available here.. I also need to know what size hose I need (or you recommend) also just any general tips you may have for me.

Thank you guys very much, I am finally seeing the light at the end of this tunnel from hell..

 

[gandalf]

Well, I listened to ocelotl's advice and started following what he advised me to do.

When I unhooked the inlet to the lift pump and rigged up a hose to draw fuel out of a container, the truck ran fine. Hot, cold, high rpm, idle... everything. Put about 4 gallons of fuel through it and it never acted the slightest bit off. Ran it for about 20 mins to 1/2 hour like that.

So, if I understand correctly, that means my problem is somewhere before the lift pump. Is this correct?

I am waiting to hear from you guys about what you suggest for my next course of action.

My thought is to remove the sending unit, blow it out with air and replace with the same unit. Then run all rubber fuel line from the tank to the lift pump. I plan to bypass the tank selection valve/switch. The water separator is already bypassed.

Is this what I should do? I could use any help available here.. I also need to know what size hose I need (or you recommend) also just any general tips you may have for me.

Thank you guys very much, I am finally seeing the light at the end of this tunnel from hell..

Sounds like you're making real good progress. Hooking a fuel can to the life pump was a very good idea. As you said, that means that the problem exists ahead of the life pump, from the life pump back toward the fuel tank. Were you able to actually drive the truck set up that way? That would be the true test, driving on an "extra" tank as you go about your business.

Are you running only one factory fuel tank rather than two? Which tank are you NOT running? If you are indeed running only a single tank, then you can eliminate the FSV, the fuel selector valve. That FSV may have crap plugging it, causing fuel starvation. If that is the case, I'd perhaps want to look at the fuel pickup in the tank. It may have no strainer on the end, and is allowing crap into the line.

Of course, there is still the possibility/probability that you have an air intrusion somewhere along the way. That could be anywhere, in the metal line, the plastic line, the rubber line, at a connection. If it is running well with the "extra" tank, then starts giving problems with the single factory tank after you eliminate the FSV, that would be something to look for.

If you run all rubber line from the tank to the lift pump be sure to secure it very well. You'll want 3/8 inch line for the engine feed line. The return line is 5/16.

 

[icanfixall]

My short answer is yes. Your fuel supply problem is between the tanks and the lift. The easy fix is run 3/8 fuel hose from the fuel tank switchover valve to the lift pump. For now just tye wrap the new line to the old like. If the problem goes away you know for sure the pluggage was in that run of line. You can then blow it out and catch the crap in a can. Actually see what the crap was. then you will rest better to have seen the crap. If the problem continues to hang around with the new line from the fuel tank swith valves then the problem is in the switch or back to the tanks. Still an easy fix. Just don't blow the crap back into the tanks again. It comes back when you suck the tanks down. You already proved something came back to plug up the fuel suction. Mel has about the best advice too. Install a fuel pressure gauge and watch it when the engine begins running bad. Then you know its a feed issue like most of us feel. A fuel tank vent plugged up can also create a vacuum in the fuel tanks making the engine run like ****..

 

[dgr]

Did you remove your fuel cap and drive around? That was mentioned earlier.

Regarding the suggestion of using a faucet supply line for a fuel line. There's a reason they don't last and the particles that are being released when it breaks down are going directly into your fuel delivery system. Hmmmm, $50 in parts to do it right or a damaged IP or clogged injectors.... Mel, aka Agnem makes a fuel supply line kit for not much coin.