what is the best setup/install to put a electric fuel pump/lift pump while keeping the mechanical lift pump for a back up..or is it needed(the mechanical pump)?

application below

what is the best setup/install to put a electric fuel pump/lift pump while keeping the mechanical lift pump for a back up..or is it needed(the mechanical pump)?

application below


I put my pump in line just after the tank switcher and remove the mech pump, replacing it with an EFI blockoff plate from a 350. you could just simple remove the mech pump and plumb the electric pump. Works fabulous for priming the system

First...what I did...this is from memory some years ago, so i might be wrong about a thing or two.
Desperate to get my truck working for me again..i did the "quick" install. I disconnected the fuel line just before the mechanical lift, hooked the fuel line to the filter that came with the electric pump, and ran a new line from the new pump to the main filter on the firewall. I wired it directly to one of those wires at the ip..I think maybe the pink one...whichever one had 12v when you turned the key on...maybe the cutoff solenoid. Thats it...has worked flawlessly for years now.

Second...what I should have done...and am going to do now that I am taking better care of my truck. After the tank goes a racor fuel filter, then the electric pump which will now be wired to a switch inside the cab. Install a new mechanical lift pump. To start, hit the switch to turn on the electric pump to prime...once started, turn it off, and run off the mechanical. This way, if the engine dies from an accident or something, the fuel stops flowing as well.

I know someone who did exactly that install with his 84, and it has worked perfectly for him.

SaintC, the second sound like a perfict set up, i am very intrested and will get on the set up right away...where am i puting the pump? after or before the mechanical lift pump... next to the filter.. any recomindations
will there be any restriction from the electrical pump being turned off?
i am thinking that the electric pump might restric the mechanical a little on the line pressure... also, would there be any harm in running the electrical pump at the same time as the mechanical? no damage i hope...probly just a high line pressure like 12psi,right:ro):muahaha:
the switch in the cab would be an on/off switch? simple

thank you every one for the fast replys, much abilged!

I was wondering about the restrictive nature myself...but no...it is not a problem. As for running both together...I doubt that would be a problem as I believe the IP and injectors dictate the actual fuel delivery to the cylinders.

Use the frame rail on the passenger side, since that is where everything is anyway. The fuel hose from the tank (or tank switch) runs along that frame to the lift pump. Like I said, I have not done this yet. I have all the parts, but I need to finish up my underside work first before proceeding with this little project.
The cab switch...any ole off/on toggle type will do. The amperage is very small.

After the tank goes a racor fuel filter.

where do you plan on mounting that? not like theres alot of room down there.

Good question...dont know yet. I think he mounted the racor and electric somewhere towards the front, and around the middle of the rail. You may have to get creative.

In my haste to get installed, I mounted my electric on TOP of the frame rail. I took some pics. As you can see, the filter that came with the pump is the ORIGINAL FILTER from years ago, and it is meant for gas, not diesel. Shame on me...I told you I had been neglecting my truck.

There is a good amount of room along that rail...I dont know yet, but I might mount everything there for easy filter cartridge replacement. Just mount a nice bracket directly to the rail, and suspend the filter in the engine compartment near the a/c hoses and stuff. Not sure yet...

my idea for the install would be to do a electrical fuel pump, pumping from the tank to the mechanical. so that i could have the electrical fuel pump to prime the system, i would have a on/off toggle in the cab, then after the engine is started turn off the electrical and have the engine run off the mechanical.

my problem is that if i have the electrical fuel pump behind the mechanical pump will the mechanical restrice the forward fuel system becuase the mechanical pump is not free flowing? the electric pump would be puting pressure to the mechanical and only between it? or am i mistaken, that is why i asked. does any one think this system would work... has any one put this sytem on there truck, with success?

thanks every one for the responses!:ro)

I don't see any problem with your setup, guys over on the diesel page run this setup also. I would personally would bypass the mechanical pump

Keep this in mind, if the membrain in you mech pump fails your electric pump will fill your engine up with diesel fuel.

Here is the wire diagram I created for my electric pump, works great. If you wanted the electric pump only to prime your system set it up to switch on when you glow plugs are cycling.

http://www3.telus.net/gmc62td/engine_harness.htm
http://www3.telus.net/gmc62td/Images/lift_pump_wiring.jpg

NICE DIAGRAHM!!!! What did you use to make that?

Excellent tip on using the glow plug circuit instead of a toggle. I like the "auto" nature of that. It also elimates any potential problem when someone else drives your rig...not that you should be having any problems to start with :-)

I did this basic setup with an old 78 van gasser. It would sit for days and days...and would take way too much cranking to get the gas to the carb. Already having this idea and info...I bought just any old electric pump from ebay for 10 bucks, put it near the tank, and wired a toggle near the keyed ignition switch. I would put the key to acces...hit the toggle...and you could hear the pump making its noise faintly from underneath. What was cool...it had this sorta click click click sound that started off fast, put as the line was pressurized, it would slow down, and then stop. Crank the enginee...starts up in 3-7 seconds, click off the toggle to run off the ole mechanical, and it worked just great.

The electric does not have a problem pushing fuel through the mechanical, and the mechanical has no problem sucking fuel through the electric. Sweet

Another "add-on". I use a Hobbs pressure switch, two screw terminals, normally open, closes under pressure. I tee it into the oil pressure sender passage. I connect an Ign feed wire (hot in the start/run position) to one side of the switch. I connect the other side of the pressure switch to the pump. In the event of engine failure, when oil pressure drops, the pump stops. Saves pumping "fuel on the fire" in case of an accident.

In addition, I connect a momentary push-button switch from Ign to the fuel pump side of the afore-mentioned pressure switch for priming the system. In order to make sure of adequate power to the fuel pump, I've used a Bosch 87A relay in these systems as well. With or without a relay, the system is safe and does what was intended.

I used this system on gas engines with worn fuel pump lobes on the camshaft. Inherent problem with Chrysler slant six engines in the '80's. Saves replacing the camshaft. Use a Delco vane-type pump, 5-7 psi output, continuous duty. Pump runs smooth, no rattling noise, just like the new vehicles with the in-tank vane pumps!

NICE DIAGRAHM!!!! What did you use to make that?

Thanks ... I used MS Visio for the diagram.

I am using a pump designed for a 90's truck so I hear the pump priming, that's good in a way because I can hear the change in tone when the system in primed up. Once it starts the engine is too loud to hear the pump running.

what is the best setup/install to put a electric fuel pump/lift pump while keeping the mechanical lift pump for a back up..or is it needed(the mechanical pump)?

application below
O posted a real good link a few months ago on this . if you view the posts go down to where I posted about electric Fuel pump updates. Its a liink from another diesel site. Great link.

thanks every one,
i have now got the fuel pump in and running on a switch before the mechanical lift pump it seems that the mechanical block pressure for the most part but i am going to install a fuel pressure guage and will find out soon.

Another good trick when running an electric with a manual pump is to have a tee fitting on the electric pump with a check valve, that way, if the electric pump is off, fuel can flow through the check valve unrestricted to the mechanical pump, and when the electric pump is on, the pressure forces the check valve shut. Carter includes this check valve set up on their kits for PUSHER pumps that are very common for guys running 24v cummins.