Fuel pressure issues...any suggestions?

[snorth88]

Hello,

I've got a Bigfoot that I've recently converted to an electric fuel pump because of fuel starvation issues on hills.

The pump is a 3-6psi unit ( I'm not sure what 3-6 psi means, does it vary from 3-6psi? based on what?) Anyways I also put in a 1-4 psi holley regulator with a pressure gauge, and then tried to regulate it down to a dealer recommended 2 psi carb input.
The trouble is I can't seem to get a steady fuel pressure. I thought a regulator was supposed to "regulate" to a steady output pressure that it's set to regardless of input pressure? I've checked the gauge accuracy with another gauge and they are both reading the same.

The higher the RPM's, the higher my fuel pressure rises. It will drop down to 1psi at idle, and upto 4 when I rev it up. It seems to be running okay...but I'm not sure if this is acceptable or not. See attached pic for setup I am running.

Thanks for your replies.

[rodp]

I would think it's due to voltage rising when the engine is revved, I'm surprised it makes that much difference to be honest. You may want to check out charging circuit and make sure all terminals are clean, see if it smooths out the voltage at all. Other than that, perhaps a voltage stabiliser or regulator, someone with a little more electrical experience may have more input on this matter ?

[Tomo]

hi
First check the voltage at the battery posts idle to fast idle approx. 14 volts
If it is low at battery check at regulator on the engine
If it is ok u have voltage drop in the wires/connections
If it is not reading as per specs the windings need there out put checked if they r ok the fault is the regulator

U may need to run a good /large earth cable engine to the battery also

It will help with the manual to find the winding voltage and other specs

The assumption is that the fuel pump is wired from an ignition source [engine on ]. Next u need to relay this wire so u can get direct fused supply from the battery . Finally run an earth wire from the connection on the pump or its metallic body back to the battery . This wiring removes all possibilities of voltage drop.

Using up to 6psi pump should not make to much difference EXCEPT seeing u have issues and most small engines r rated at 2-4 psi ,I would stick the correct ump on it

tomo

[snorth88]

Ok thanks for your help you guys.
Um by correct pump, what do you recommend to use? Would I need to use a fuel regulator?

Thanks again!

[Tomo]

HI
I would make sure the electrical is spot on first before blaming the pump .
Although many manuals will tell you that a higher pressure may push open the float needle on occasion but u have installed a regulator so in theory should be fine .

tomo

[snorth88]

Hi you were right on, I used a relay and everything was working great...could adjust fuel pressure to steady 1.5 to 2 psi. But....ran my battery very low doing a bunch of successive winching on her maiden electric fuel pump voyage, ended up stalling and wouldn't start. Switched back to my old pulse pump on the trail and then used my recoil to get fired back up. I then went and bought a new plastic pulse pump that replaces the older style metal Mikuni( I now carry it as a spare). The Argo is running beter than ever now. I'm going to stick with the pulse pump.

Thanks for your help!

[ARGOJIM]

Hi you were right on, I used a relay and everything was working great...could adjust fuel pressure to steady 1.5 to 2 psi. But....ran my battery very low doing a bunch of successive winching on her maiden electric fuel pump voyage, ended up stalling and wouldn't start. Switched back to my old pulse pump on the trail and then used my recoil to get fired back up. I then went and bought a new plastic pulse pump that replaces the older style metal Mikuni( I now carry it as a spare). The Argo is running beter than ever now. I'm going to stick with the pulse pump.

Thanks for your help!

Simple is good. They are cheap enough to carry a spare.
All that fancy crap makes it nice when it's all new and nice, but....