EFI fuel starvation issue.

[chuzie]

I am having a fuel starvation issue on the trails.

Here is my system

Vented fuel cap
Wild Horses EFI 23 gal tank
LP pump mounted to frame rail right next to tank with pre-filter
HP pump mounted on driver fender will
BC accumulator
Fuel press gauge tapped at fuel rail
Return line back to accumulator
Return line back to tank
Vented fuel cap
No aux tank

On 3 separate occasions I have been starved of fuel on the trail which has initially appeared as though my tank being empty. Each time I am off camber either nose up, passenger side down, or a combination of both.

The most recent occurrence I added 2.5 gal on level ground and finally got it primed and started after multiple priming attempts. When I filled up at the station I calculated I had 12 gallons of fuel in the tank at the time of the starvation. My fuel gauge is not operational. My fuel pressure gauge indicates 20 PSI during these incidents but my HP pump is new and confirmed operating during these incidents. Also, the most recent incident occurred within an hour of installing a new LP pump and filter.

I am thinking about installing a LP gauge after the LP pump to aid in troubleshooting but I also am considering removing the tank for inspection. of the pickup.

Looking for thoughts on this issue to aid in troubleshooting tomorrow.

Thx.

 

[garberz]

I don't think there's anyone left in the Socal Bronco group that still runs an accumulator. There's just been too many issues. Ditch the LP pump and accumulator and run the HP pump next to the tank. Seems to work just fine. I'm sure others will agree. No aux. tank keeps it simple.

 

[chuzie]

The accumulator was installed in an attempt to rectify this starvation issue after the second incident.

I am reluctant to remove the LP until I have isolated the starvation issue and eliminated the tank as a player for fear of losing HP pump prime. I am all for removing the LP pump, don't get me wrong, but identifying the issue is my first order of business.

My luck would have this reoccur after moving the HP to the back of the system.

 

[Viperwolf1]

Very similar to my setup. In my experience the LP pump can't always keep up with the HP pump. I replaced mine with a carter P4070 and haven't had a problem since.

 

[NYLES]

Im going with VW advice he gave me which was high pressure at the tank dump the accumulator and return to the tank

 

[chuzie]

i do run the P4070. That is why I am looking at the tank rather than the rest of the system. I just don't understand.

 

[NYLES]

it pointed straight up when this happens?

 

[NYLES]

here a mod i havent tried but the source is a wheelin fool......he said go to a bobcat dealer and get a wiegthed pickup kit and $17 it will follow the fuel in the tank...like i said i aint done it but it supposed to follow the fuel in the tank at whatever angle and you never lose fuel pickup

 

[Viperwolf1]

i do run the P4070. That is why I am looking at the tank rather than the rest of the system. I just don't understand.

In that case, drop the tank and checkout the pickup. If it looks ok move the HP pump to the rear and ditch the LP pump and accumulator.

 

[chuzie]

Nyles, No more than 30 degrees nose up at the most and that pickup idea is cool!

The pickup is supposed to be just a tube with no strainer, according to wild horses. I plan to drop it tomorrow and take a look. Guess I will be buying some EFI line too. $$$

So much for my expensive accumulator.

One thing that alarmed me when I was changing the LP pump the other day was the fuel that I took a bath in because I was on an incline like a moron, turned my clothes brown. It was all new fuel so I am not sure if it was rust or a chemical reaction of the fuel with the clothes, but I had never seen that before.

 

[NYLES]

changed ya filters lately? jus a thought

 

[chuzie]

Brand new filter behind brand new LP pump.

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[airbur]

There is no pickup per se in these tanks. The fuel pump is the pickup. At least that's how mine is with a HP Aeromotive pump in the tank. There is, however, a mesh filter on the pump.

I'm betting the short run of hose from the pump to the tube is broken, loose, or falling apart. It's been known to happen as the hose that comes with the tank is not high quality.

 

[Viperwolf1]

I'm thinking tank to engine compartment is a long way to send low pressure fuel. And since the HP pump is sucking on it it's even lower pressure than would normally come from an LP pump. Add in heat from the exhaust system and you have a recipe for vapor lock. Now if the HP pump was at the rear the pressure would be about 35 psi for that long run and vapor lock wouldn't happen.

 

[spap]

I have heard that if the return line goes back into the accumulator it can cause bubbles .
Maybe when it stilted it crating bubbles in the accumulator and that would explain low fuel pressure when tut happens I now you have two returns. Try it with out the return to the accumulator. At least it s cheap test

 

[chuzie]

This is an old WH efi tank about 12 years old. So no in tank pump and no strainer.

This occurred before and after accumulator.

Since I am only running 19# injectors, I guess 35 psi won't matter. Worth a try.

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[chuzie]

Pulled the tank. The pickup comes straight down the wall from where is exits to the pump on the driver side. Heads to bottom of tank and bends 90 degrees pointing to passenger side. Terminates about 2".

So the pickup is on driver side and all the way to the front which may explain why I starve nose up or driver side high.

Gonna add some fuel to the tank and see how what quantity will uncover the pickup.

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[chuzie]

With 5 gal the pickup is uncovered at:
17 degrees nose up
26 degrees pass side down
5 degrees when combined with both axis

With 10 gal the pickup is uncovered at:
26 degrees nose up
43 degrees pass side down
15 degrees when combined with both axis

So solution one is modify my trail habits and never have less than 1/2 tank and be aware of my angular limitations and how long I can exceed them with my accumulator

Or

Cut open my tank and install a different pickup system.

Crap!

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[KyleQ]

It looks like all your fancy parts are letting you down when simple redneck ingenuity seems to work flawlessly for me...



Stock tank, fuel filter, HP pump - worked flawlessly with my 302 and 351, I can drain the tank bone dry with this setup... Never a hiccup on the trail-

My return line dumps into the filler neck as well - no bubbles in the fuel flow either.

 

[chuzie]

Running efi with a stock tank? Good on ya. Fortunately the only fancy part letting me down is the pickup in my tank. Good to know all my other fancy items are working as designed.

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