Automatic Fuel Pump shutoff?

For everything related to using Fuel Injection in an FSJ.
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Topic author
PUDS
Posts: 114
Joined: Mon May 30, 2016 4:37 pm

Automatic Fuel Pump shutoff?

Post by PUDS »

Came across this a while back, haven't finished wiring my Fitech system but am interested in implementing this concept on my waggy. Anybody done this on their rig?

http://www.how-to-build-hotrods.com/ele ... -pump.html




1988 GW 360/727/NP229
4" BJ'S Lift
Thorley Headers/Magnaflow Exh
Edelbrock Intake
Fitech TBI (in the works)
32" BFG KM2'S
Razor Grill
///This is a project vehicle///

cmaje72
Posts: 212
Joined: Thu Jul 07, 2011 6:33 am
Location: Western NY

Re: Automatic Fuel Pump shutoff?

Post by cmaje72 »

Its a very good idea to do that.
Also in my CJ with the 5.0 swap there is an interia switch which will cut the pump in the event of a hit hard enough to trip the switch. So you could implement it in that way too.
79 Cherokee 5.3/4l65E/NP241C
79 CJ7

will e
Posts: 5096
Joined: Sat Aug 18, 2012 8:21 am

Re: Automatic Fuel Pump shutoff?

Post by will e »

For fuel injection it will also act as an automatic cutoff it you happen to lose oil pressure for another reason. This can be either good or bad depending on the situation. Your FiTech system may have a fuel pump output that you would use to trigger a relay. This would be a better option and will provide a 'quicker' cutoff of the fuel pump since it will most likely be based on ignition input.
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge

Topic author
PUDS
Posts: 114
Joined: Mon May 30, 2016 4:37 pm

Re: RE: Re: Automatic Fuel Pump shutoff?

Post by PUDS »

will e wrote:For fuel injection it will also act as an automatic cutoff it you happen to lose oil pressure for another reason. This can be either good or bad depending on the situation. Your FiTech system may have a fuel pump output that you would use to trigger a relay. This would be a better option and will provide a 'quicker' cutoff of the fuel pump since it will most likely be based on ignition input.
Thanks. Looked it up and you're right, Fitech has a fuel pump trigger than can be used with or without an external relay (can handle 15 amps on its own direct to pump) and shuts pump down when it loses RPM signal. The direct connection is there so you can use a pump that is capable of Pulse Width Modulation so you can slow down the pump during low fuel requirements. I'm not going to bother as I don't think my Walbro is capable of PWM, and I'd rather use the Fitech just to signal an external relay to avoid such a current draw through the computer. One less thing to worry about! Image

1978 Cherokee/Wagoneer 360/727/NP229 (soon NP208)
4" BJ'S Lift
Thorley Headers/Magnaflow Exh
Edelbrock Intake
Fitech TBI (in the works)
32" BFG KM2'S
Razor Grill
///This is a project vehicle///

will e
Posts: 5096
Joined: Sat Aug 18, 2012 8:21 am

Re: Automatic Fuel Pump shutoff?

Post by will e »

I like the idea of using a relay to avoid the current draw through the computer. The old Holley PROJECTION units were known to have issues with a directly attach fuel pump. The relay is another point of failure but carry a spare and you should be good to go.
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge
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