crappy road trip on the 4th

[rastiss]

Bucky was giving me fits. Last summer I had it act up 3 or 4 times when it was really hot outside. Edelbrock Carb 302. Previous owner put an inline electric fuel pump on it. Over the winter I replaced the rear tank with a 23 gal from BC. New tank was blown out really well with air before installation. New filter. Running down the road it randomly starts cutting out and slowing down and usually ends up dying. Fuel pump still runs but no fuel in the clear fuel filter. After sitting a couple of minutes, the filter fills, it starts right up, go a few miles and it does it again. Took 2 hrs to drive 50 miles to Lawton. I replaced the electric fuel pump, didn't change anything. I tried running a fuel hose outside the frame and routed it different way thinking it must be vapor lock. Tried running with the fuel cap loose. When it cools off its fine. My next thing to try I guess is a phenolic carb spacer. The only different from last year besides the fuel tank is the grille I made. Since it isn't overheating its hard to believe that would do it but maybe its changed airflow? Didn't seem to make any difference running with the wind or against it....

 

[BRONCROB]

Do you have a pickup screen in the tank? I had the same problem caused by my pickup being clogged with crap.I could blow back through my line and it would be good for a while,but finally replaced my tank.

 

[rastiss]

No screen in the tank. The inline pump does have a small pre filter that came with the new pump. Like say, new tank. I switched between both tanks and it seemed to be slightly running on the front.

 

[SHX669]

What type of inline pump and how far from the fuel tank and where is the pump mounted?
SHX

 

[bronconut73]

Are you still running your aux. tank and manual tank switch valve?

 

[rastiss]

Pump is mounted on Lt frame rail between the tanks.


Old pump

Replacement pump

 

[rastiss]

Are you still running your aux. tank and manual tank switch valve?

Yes on both. It seems to run "slightly" better on the front when it's acting up. I have NOT tried bypassing the the switching valve. I've never seen a manual valve give a problem other than leak....

 

[jw0747]

You certain it's a fuel delivery problem? Years back mine was doing the same thing and I changed the f.p. twice and it made no difference. Turns out it was an ignition problem caused by a bum pertronix pointless unit.

 

[El Kabong]

A leak at the valve that allows air into the lines would keep the pump from being able to draw fuel. like a straw with a hole in it. You could try running directly from the tank to pump & see if it helps. Since it happens with both tanks, it seems like the issue would not be in the tanks themselves, unless they had similar problems at the same time.

While the valve is disconnected it would be a good time to blow backwards thru it to dislodge any bugs that might be stuck in there (Old family story about a small plane having trouble due to a bug stuck in the switching valve, blocking supply from both tanks). Since the valve is the only thing common to both tanks that is before the new pump & line, it seems like a chunk in it or an air leak would be worth a check.

 

[rastiss]

Fuel pump is on its own circuit with its own switch. If the pump is running but no fuel in filter its either vapor locked or restricted I'd think.

 

[blubuckaroo]

I'm confused.?:?
How can the pump be back between the tanks with the manual selector valve still in service?

 

[tbratz]

Mine would do the same thing and it drove me nuts. After changing everything it still continued to have the same problem. I finally replace all of the fuel line including the solid line running along the frame and the problem stopped. I figured somewhere in one of those lines was sucking air.

 

[rastiss]

I'm confused.?:?
How can the pump be back between the tanks with the manual selector valve still in service?

2 tank hose to selector, one to pump, pump to carb. Electric pump can be mounted about anywhere...

Its always worked. Temperature is definitely a factor on this. No problem when cool. Sucking air on valve could be s possibility. It would take more draw to get it from rear tank which could explain why it runs better on front?

 

[BRONCROB]

I would try eliminating the valve and connect straight to either tank.The heat may be causing some of your issues or a valve leak.When the float closes on your carb it could let the fuel heat in the line and push it back through your pump into the tank causing it to loose prime.Those elec. pumps like to push more than pull so placement may also be a factor.I would also disconnect from the carb and run fuel into a can to check flow and to see if your pump has a check valve that holds fuel when it's not running.Hope this may help,I know how much of a pain in the ass it is first hand.:banghead:

 

[SHX669]

On a Bronco I like the inline pumps like that way better than the rotary style pumps. I see Holley has one now that is supposed to have capability of 12" lift .
I have better luck with my rear fuel tank than my Aux. I always figured it was because it has a more gentle rise/incline before it ties into the fuel selector valve. My Aux rises up pretty quickly from the tank outlet to go over the frame.
like the others ; by pass the selector valve - use one tank - see what happens.
SHX

 

[blubuckaroo]

2 tank hose to selector, one to pump, pump to carb. Electric pump can be mounted about anywhere...


No, an electric pump should be back by the tank. As stated, they push better than suck. I know you can see them everywhere but back by the tanks is best. A good option, if you have dual tanks, is to also put both the pump and an electric selector valve back there. The space on the frame on the drivers side frame between the two tanks makes the shortest possible suction lines. Also vapor lock will be practically impossible.

 

[rastiss]

As long as it is mounted within its "lift" specs, mount area is universal. I do know that closer to tank is better. Having said that, what has changed?

 

[rastiss]

I just bypassed the valve. There's less than 18" of hose on suction side. I'll give it a try like that. Since I now have an extra pump I may run separate pumps for each tank assuming this works.

 

[rastiss]

We put a little over 50 miles on it this evening with a mix of city and country driving. It is a little cooler tonight but no issues so far. Fingers crossed...

 

[blubuckaroo]

And now??:?