• Hello Guest, we are proud to now have our Wiki online that is completely compiled and written by our members. Feel free to browse our Jeep-CJ Wiki or click on any orange keyword when looking at posts in the forum.

Fuel pickup question

Highlights Only
Fuel pickup question
GatorBate

GatorBate

Senior Jeeper
Posts
746
Media
57
Thanks
2
Location
Utah
Vehicle(s)
81 CJ5 Renegade, 304,TBI, PaceSetter Headers, T-177, D-300-4:1, AMC-20, D-30,(OX Lockers W/Electric Shifters),3.54, XRC8 winch. OME 2" lift
I'm looking for a way to solve the problem of running out of gas when my tank is half empty and I'm going up a steep hill. All the gas flows to the back of the tank leaving the pickup tube high and dry. Well maybe not dry, but it can't reach the fuel.
 
Make sure the pickup is close to the bottom of the tank, and near the center.
LG
 
Stock tank ?
Pick-up filter on end of tube ?
Filter adds about 4"length to the pickup.
 
Your biggest problem with this is TBI. With a carb you have enough fuel in the bowl to get past the pickup being uncovered periodically. With FI, it dies about 3 secs after the pickup is uncovered, as soon as the pump loses pressure you are done. Factory FI setups have baffles around the in tank pump to prevent this. Some folks run an accumulator tank between the main tank and the throttle body. Holley Hydramat is another option you might look at since you could retrofit that into your existing tank. I solved this problem on my TBI setup by building a custom tank with a built in accumulator. There are several ways around this so hang in there.

Dave
 
oops....didn't see he was FI.
As mentioned above, the accumulator tank will most likely solve the problem.
Lots of folks have done this.
 
Back in the mid eighties I rented a jeep in Ouray. Even going up small inclines the motor would die.

When I returned it, I told them. The guy said "oh that's the one". He had replaced all the other rental fleet but missed this one. My point is they were weak fuel pumps. Check your pressure.

With half a tank you should have almost 4 ounces of gas in a 1/4" x 12' line. (231 cubic inches per gal)
 
He is fuel injected, once pump loses prime and pressure falls off, engine quits right there, game over.
 
I know what an accumulator tank is, but what are people using for one?
 
The accumulator sounds like the way to go. Do you have any pictures Dave?

I'm trying to think how that would work. Do you put a accumulator tank between the fuel pump and the main tank. That way the pump draws from the accumulator tank while the main tank pick-up is uncovered and then the accumulator would refill as soon as the pick-up was back in the fuel again? How big would this accumulator need to be?
 
I would like to see this setup also. I installed a tbi around 10 years ago and have had no stalling issues related to low fuel in the oem tank. And yes, I have been up and down numerous steep grades.
 
Torx are you running a OEM fuel pump on the engine block also ? I thought you pretty much had to go fuel pump in tank.
 
https://www.speedwaymotors.com/FiTe...MIiYbh1-br1wIVxbrACh2fVQkkEAQYCyABEgIUn_D_BwE

FItech makes this system which mounts under hood and uses the original mechanical pump to keep the sump full. The injection pump is mounted in the sump.

Holley 12-130: In-Tank RetroFit Fuel Module 255 LPH Pump w/ Hydramat | JEGS

Holley (and others) also make these tank retrofit setups as well.

The theory behind the accumulator is you use a pump drawing from the tank pumping into the accumulator and returning back to the tank which keeps accumulator always full. Then a pump either in the accumulator or drawing from it supplies your fuel injection system. Accumulator capacity can be from a quart to as big as you have space for. The accumulator is not necessarily the best option, just one of several.

Torx, on the street, even on fairly steep mountain roads you may never see a problem, it's when you are off-road in terrain that pitches your vehicle up or down well past the 20% grade you might encounter on a road that issues pop up. This behavior is a frequent topic of discussion on off-roading forums.
 
Last edited:
Belizean said:
Torx are you running a OEM fuel pump on the engine block also ? I thought you pretty much had to go fuel pump in tank.
Click to expand...

The only pump is electric and is mounted mid way on the frame. Actually, the fuel pretty much siphons itself to the pump, per Howell tbi instructions. The tbi does fine with around 10 psi.
 
Thanks for that info Dave, That will give me something to think about since I have always been curious about running out of gas on a hill. So far I have taken many rides up a long steep hill where looking thru the windshield is useless. I try not to go below a 1/4 tank and carry spare gas, just in case. Sometimes checking if the pump is hot or not and changing fuel pumps is pretty easy due to its location.
 
Electric fuel pumps are 'pushers', and need to be as close as possible to the fuel supply.
Mechanical fuel pumps are 'suckers' and have no issue pulling from the tank.
Have you checked to be sure all fuel line connections are tight and you are not suc'n some air.
Have you ck'd FP pressure at the engine?
When did you last change the fuel filter?
LG
 
This is a problem that the jeep has had for a few years. I just keep the tank full and its ok. Last year the wife and I wheeled into a lake up in the high country to do a little fishing. That evening as we were driving up the last climb to the lake it started to cut out and die. I put in some gas even though I still had half a tank and it ran fine the rest of the weekend.
Right now, it just started giving me other problems that act like plugged filters or leaks. So I am going to be tearing into it and I thought while I was there I would try to fix this the pick-up problem too.
 
I believe the Holley 'HydraMat' works on the same principle as those Walbro units, its just one large piece instead several smaller ones.

Dave
 
GatorBate, another thing that can stall your engine is vacuum in the fuel tank caused by improper venting on the tank. This can be easily checked by removing the gas cap after a good drive and listening for air rushing into the tank which would indicate vacuum. The later CJs have two check valves and the charcoal canister plus a lot of tubing in the vent system.
 
You must log in or register to reply here.

Jeep-CJ Donation Drive

Help support Jeep-CJ.com by making a contribution.

Help support Jeep-CJ.com by making a contribution.
Goal
$200.00
Earned
$0.00
This donation drive ends in
0 hours, 0 minutes, 0 seconds
  0.0%
Contribute
Back
Top Bottom