external fuel pump for renix?

my new-to-me comanche just crapped it's fuel pump. i am on a tight budget at the moment-read unemployed, and i have a friend who's into racy car stuff. he has several different "universal" inline high pressure fuel pumps, he says i can have any of them to try and make work. there's an msd, a holley, and i believe a carter. i have looked up the specs on them and they all run basically about the same psi and gph as the stock pump. i don't see any reason why this wouldn't work, as there's a ton of room right around the tank to mount the pump. anyone done anything like this? any catches i'm not thinking of? the only issue i have to work out, is how to extend the old pump outlet line on the hanger down to a "pick up" thing. i've got plenty of fuel injection hose, strainers, filters, metal line, etc. i'm assuming the rail mounted regulator should be able to handle it's duties even if the pump is a slightly higher pressure than stock.

as long as crud in the tank did not cause your original pump to quit and you are close on presure it should be fine

If the old pump is not on the hanger, a piece of fuel line to the floor of the tank could do, or use a small piece to add a short section of steel line. Securing it at the bottom so it doesn't swing around might help.

Splicing in the new pump on the frame rail is a cut and paste kind of thing, just use fuel injection hose for the connections. I'd run power from the factory electric with short adapter leads to reduce the rewire confusion. That way it would start and run just the same. Amp draw would be the only concern - it can't be any higher than stock or it'll burn up the factory wiring.

Factory pumps run about 42 pounds, the fuel regulator should be able to handle others in that range. The only other concern is to check how much suction they can tolerate - too long a distance from the tank may keep one from siphoning fuel well or cause a lot of crank time.

My neighbor and wheelin buddy has a 90 XJ and he went external on it. Check his build thread on our local forum and see how he did his. Starts around post 25.

thanks guys. i'm going to give it a go. going to use a piece of steel line w/ a sort section of FI hose to make a pick up, i'll be using the lower part of the hanger where the pump used to sit to keep the "pick up" in one place. found a couple spots i can mount the pump that are both close to the tank, and lower than the sender outlet-but still out of harm's way. i'm going to check that link right now.

post up pics when you get this done....this is on my list.

My Comanche runs an Aeromotive A1000 pump externally mounted with no problems. It was noisy at first fire up until it primed, after that it's a siphon effect.

I cut everything off the pump/ sender plate except the level sender bracket, welded the holes solid, then redrilled for AN bulkhead fittings and sealing washers. On the backside there's a detachable pickup tube and a return tube. Then it's just a matter of connecting AN flex line to the rest of the system. Probably extreme overkill for most applications, though.

For a 4.0, I wonder if you could gut the stock pump body? Then you'd still have the stock pickup sock and outlet tube.

It was my understanding that the fuel system was supposed to run at 39psi untill 95, and after changed to 49psi. I'd have to check to see what it actually runs at. Flow rates do vary with pressure, and they vary backwards compared to what seems logical, so using a higher pressure should not deliver more fuel. So if one could rig a system that makes the pressure at the rail similar to what is should be stock, I see no reason why it would not work.

That's what the regulator's for. On a Renix, I've personally seen a guy use an older Ford 7.3 lift pump with the stock regulator and it ran perfect.. the pump deadheaded at 95 psi and the stock regulator took it in stride.

that's the way i see it working too. as long as i can provide AT LEAST 40 psi to the rail, everything else should work itself out. haven't put the pump in yet, figure while it's down, i'll fix a bunch of other minor issues. when i do get it together i'll put up some pics of my fix, and post how it's running.