Fuel pump placement.

[RangRayy]

On an '87 R10 with dual tanks can I put an external power fuel pump in front of the selector valve? I was thinking of installing the pump in the engine bay but probably not a good idea due to hear and the distance from the tanks to pump. Ditched the tbi setup and all the wires with it. No way now to kick on the fuel pumps inside the tanks unless I can hotwire them to a switch but as far as I knew the pumps needed signal from oil pressure to kick on. Can that just be bypassed? I have a mr gasket 12s pump just to get me running till I get the rear tank installed.

Will the external pump still flow enough through the selector and the pumps in the tank? I'm really trying to avoid pulling the tanks down just yet until I get the rear setup done. I also want to use the factory return line with a regulator that has a return spot on it.

I've already got the pump and trying to avoid extra work and $$$ if at all possible. Any help or advice much appreciated.

 

[foamypirate]

On an '87 R10 with dual tanks can I put an external power fuel pump in front of the selector valve? I was thinking of installing the pump in the engine bay but probably not a good idea due to hear and the distance from the tanks to pump. Ditched the tbi setup and all the wires with it. No way now to kick on the fuel pumps inside the tanks unless I can hotwire them to a switch but as far as I knew the pumps needed signal from oil pressure to kick on. Can that just be bypassed? I have a mr gasket 12s pump just to get me running till I get the rear tank installed.

Will the external pump still flow enough through the selector and the pumps in the tank? I'm really trying to avoid pulling the tanks down just yet until I get the rear setup done. I also want to use the factory return line with a regulator that has a return spot on it.

I've already got the pump and trying to avoid extra work and $$$ if at all possible. Any help or advice much appreciated.

You are pretty much guaranteed to kill that external pump if you try pulling through the top of the sender AND through the existing pumps.

Also, why not just use the current pumps? You obviously have to have a way you are powering your external. Just tie whatever that is (most likely an ignition hot, you could even run this through the oil pressure switch to maintain crash safety), into the tan/white wire that goes in the left side of the bulkhead in the engine bay. That was the original trigger wire from the ECM, it goes into the bulkhead, through a fuse, then back out of the bulkhead on the right hand side, to a small harness that goes into the firewall (tan/white, gray, and tan wires present here). The tan/white into the firewall is 12V+ to the switch on the dash, and the tan and gray wires are the 12v+ feed from the switch for the pumps (can't remember which side is which, sorry).

 

[RangRayy]

You are pretty much guaranteed to kill that external pump if you try pulling through the top of the sender AND through the existing pumps.

Also, why not just use the current pumps? You obviously have to have a way you are powering your external. Just tie whatever that is (most likely an ignition hot, you could even run this through the oil pressure switch to maintain crash safety), into the tan/white wire that goes in the left side of the bulkhead in the engine bay. That was the original trigger wire from the ECM, it goes into the bulkhead, through a fuse, then back out of the bulkhead on the right hand side, to a small harness that goes into the firewall (tan/white, gray, and tan wires present here). The tan/white into the firewall is 12V+ to the switch on the dash, and the tan and gray wires are the 12v+ feed from the switch for the pumps (can't remember which side is which, sorry).

i was thinking that would kill it. well i cut all the wires right at the firewall going to the ECM. i only saved 4 wires, pink ignition wire, alt wire, some wire that went to the coil on the tbi dizzy and the last i cannot remember. as i did that i meant to save the orange wires for the fuel relay and such but it was too late... i pulled the oil pres switch out and put my oil pres gauge fitting there.

i had wondered if i could just add 12v power source, say the ignition wire that is running to the starter, but wasnt sure if that would work or not. now it has me thinking that since i cut all the wires that the switch on the dash isnt going to work anymore...

 

[foamypirate]

i was thinking that would kill it. well i cut all the wires right at the firewall going to the ECM. i only saved 4 wires, pink ignition wire, alt wire, some wire that went to the coil on the tbi dizzy and the last i cannot remember. as i did that i meant to save the orange wires for the fuel relay and such but it was too late... i pulled the oil pres switch out and put my oil pres gauge fitting there.

i had wondered if i could just add 12v power source, say the ignition wire that is running to the starter, but wasnt sure if that would work or not. now it has me thinking that since i cut all the wires that the switch on the dash isnt going to work anymore...

If you still have the dash switch sub harness uncut, you could just put a fuse inline and feed directly to that from a switched ignition 12v+, instead of to the old ECM 12v+ into the left side of the bulkhead. The dash switch sub harness is near the throttle cable in the firewall. With any luck, you may not have cut it, since it doesn't tie into the ECM or TBI harness, just the bulkhead and then it's own dedicated hole on the driver's side firewall, behind the engine.

The downside to not having an oil pressure switch in series with the circuit is crash protection. If you still have ignition power after a wreck, the pumps would stay on. Tying into the oil pressure switch would kill the pumps if the engine quits. The downside to the oil pressure switch is a delay in fuel pump turn on, since your fuel pumps wouldn't get power until you built up oil pressure from cranking.

 

[RangRayy]

If you still have the dash switch sub harness uncut, you could just put a fuse inline and feed directly to that from a switched ignition 12v+, instead of to the old ECM 12v+ into the left side of the bulkhead. The dash switch sub harness is near the throttle cable in the firewall. With any luck, you may not have cut it, since it doesn't tie into the ECM or TBI harness, just the bulkhead and then it's own dedicated hole on the driver's side firewall, behind the engine.

The downside to not having an oil pressure switch in series with the circuit is crash protection. If you still have ignition power after a wreck, the pumps would stay on. Tying into the oil pressure switch would kill the pumps if the engine quits. The downside to the oil pressure switch is a delay in fuel pump turn on, since your fuel pumps wouldn't get power until you built up oil pressure from cranking.

So to be clear... Splice off the ignition wire to the starter with a fuse up to the sub harness, bc I agree I more than likely left it alone like you said it's not tied into the ECM or tbi wires?

Well since I cut the relay off maybe I could just rewire up a new relay that connects into the oil pressure switch. I believe I've seen them online somewhere.

 

[foamypirate]

So to be clear... Splice off the ignition wire to the starter with a fuse up to the sub harness, bc I agree I more than likely left it alone like you said it's not tied into the ECM or tbi wires?

Well since I cut the relay off maybe I could just rewire up a new relay that connects into the oil pressure switch. I believe I've seen them online somewhere.

You'll need something that stays hot when the ignition is in crank and run positions, so that rules out the starter solenoid wire (it's only hot when cranking). The large pink wire coming off the bulkhead in the engine bay that went to the TBI distributor would work, if you still have it.

If you can recreate the TBI setup with the fuel pump relay and oil pressure switch, that would be your best option.

 

[RangRayy]

You'll need something that stays hot when the ignition is in crank and run positions, so that rules out the starter solenoid wire (it's only hot when cranking). The large pink wire coming off the bulkhead in the engine bay that went to the TBI distributor would work, if you still have it.

If you can recreate the TBI setup with the fuel pump relay and oil pressure switch, that would be your best option.

That was one of the wires I did save. I had planned on tieing in the electric choke to that wire. Probably not a good idea to have it overlaoded. But I suppose I could fine another source for that.

I have all the wires in my garage still and they're just cut and still bundled together. I know it's an orange and orange/white set of wires for the oil switch up to the relay. There were some other wires for that went to the relay too so going to have to dig and research them.

 

[highdesertrange]

I sure hope you are not trying to run those high pressure pumps directly into a carburetor. highdesertranger

 

[RangRayy]

I sure hope you are not trying to run those high pressure pumps directly into a carburetor. highdesertranger

no through a regulator with a return port to drop the pressure down between 4-7psi

 

[RangRayy]

Anyone have an idea if this will work for a temporary till I get the rear tank figured out?

12 gal metal cell in the bed that just has an outlet and a vent hookup on it. Run a single line fuel sytem until I get a better cell with a return on it. Line from the outlet to an electric pump with a filter on it and only runs 35gph and 4-7psi to a regulator with the return port blocked off and pressure is set automatically at 7 on the regulator so drop it down to about 5.5,6ish then to the carb with another filter.

I read that the pump would be okay as long as the regulator psi matched the pumps psi. Anyone have experience with this?

Also I'm looking at cells and a lot I see have 2 outlets on the sump; can one be used for outlet and the other a return? Or does the return have to be ontop of the cell?