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914World.com _ 914World Garage _ Fuel pump relocation wiring question
Posted by: scott_in_nh Oct 14 2012, 08:56 AM
So a couple of weeks ago I decided it was time to take care of a few projects on my 74 2.0 D-jet.
A PO moved the 3 port fuel pump up front under the steering rack, but never replaced the plastic fuel lines.
The fuel pump works ok, but is noisy and doesn’t hold pressure when I shut the car off.
The wiring for it was also cobbled – two wires were run through the tunnel and plugged into the original fuel pump plug, but apparently the positive wire failed so another wire was run from the relay board through the interior and to the pump.
It was still grounded through the tunnel wire and original pump harness.
I installed Tangerine SS fuel lines and replaced all other rubber lines I hadn’t already replaced and now I am installing a 2 port fuel pump and filter in the same location.
The layout proved quite challenging, but I think I have a good solution.
My question is can’t I just run the positive wire through the tunnel and ground the fuel pump in front?
I did a search and some refer to running “wires” (plural) through the tunnel and some talk about running “a wire”.
I just want to make sure I’m not overlooking something…..
Posted by: SLITS Oct 14 2012, 09:10 AM
Why not? The original ground point is the multi-ground under the relay plate. So pick up the positive from the harness (I ran it back thru the tunnel) and ground the pump where you have relocated it.
Posted by: reharvey Oct 14 2012, 01:50 PM
I've done it this way on five cars without a problem. Ray
Posted by: SirAndy Oct 14 2012, 01:58 PM
Doesn't the FI brain control the pump by controlling the GROUND???
In which case your pump would run all the time as soon as you turn on the key ...
It's been a while since i dealt with the stock D-Jet, so i could be wrong on that.
Posted by: timothy_nd28 Oct 14 2012, 02:34 PM
IMO, the fuel pump is too important to be not grounded correctly. I ran heavy gauge wire from the neg post of the battery to the fuel pump area. This wire was then grounded to the body near the fuel pump. Then I ran a small jumper from the new body ground to my fuel pump. It gives me peace of mind having a dedicated ground for my pump, yes it may be overkill.
Posted by: Dave_Darling Oct 14 2012, 03:52 PM
Doesn't the FI brain control the pump by controlling the GROUND???
Nope. The FI grounds a pin on the relay, which sends power to the pump or not. So it controls power to the pump, by controlling the ground to the relay.
--DD
Posted by: SirAndy Oct 14 2012, 09:44 PM
Nope. The FI grounds a pin on the relay, which sends power to the pump or not. So it controls power to the pump, by controlling the ground to the relay.
Aha, i knew there was something about the brain and ground for the pump. Ground for the relay it is then, makes sense.
Posted by: scott_in_nh Oct 15 2012, 07:17 AM
Nope. The FI grounds a pin on the relay, which sends power to the pump or not. So it controls power to the pump, by controlling the ground to the relay.
Aha, i knew there was something about the brain and ground for the pump. Ground for the relay it is then, makes sense.
Thanks for clearing that up!
What a pain upgrading the fuel system has been!
Tangerine's SS lines went in easy enough, but finding room for a 2 port pump and filter under the steeering rack AND getting it plumbed to the tank AND fixing poor work by PO's ended up being more difficult then drilling and welding the from swaybar mounts (my other project while the tank was out)...
Posted by: scott_in_nh Oct 15 2012, 05:46 PM
Getting closer - the new pump is in, wired and runs properly when the key is turned on.
I also test fitted the last two hoses, the ones that actually go to the tank.
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Posted by: scott_in_nh Oct 17 2012, 07:53 AM
So there are no gaskets (rubber washer?) between the pipes and the fuel tank (#11 and 13)
What are my options? The hardware store has rubber washers - what is compatible?
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Posted by: SLITS Oct 17 2012, 09:53 AM
There are fibre washers (fiber if you are Amerikan) .. whether they are available or not I can't say.
Part Numbers are:
E 914 201 147 10 (#11)
E 311 201 235 A (#13)
Whether an aluminum or copper crush washer would work I won't address.
If any flexible material was to be used, it should be Viton (Ethanol :puke: added fuels ya know).
Posted by: gothspeed Oct 17 2012, 10:40 AM
.......................................
I installed Tangerine SS fuel lines and replaced all other rubber lines I hadn’t already replaced and now I am installing a 2 port fuel pump and filter in the same location.
The layout proved quite challenging, but I think I have a good solution.
My question is can’t I just run the positive wire through the tunnel and ground the fuel pump in front?
I did a search and some refer to running “wires” (plural) through the tunnel and some talk about running “a wire”.
I just want to make sure I’m not overlooking something…..
+1 .......... I am in the midst of doing this fuel pump 'wiring' myself ......... where or how did you get the wire past the engine firewall into the tunnel? Did you drill a new hole with a grommet?
Posted by: scott_in_nh Oct 17 2012, 11:02 AM
.......................................
I installed Tangerine SS fuel lines and replaced all other rubber lines I hadn’t already replaced and now I am installing a 2 port fuel pump and filter in the same location.
The layout proved quite challenging, but I think I have a good solution.
My question is can’t I just run the positive wire through the tunnel and ground the fuel pump in front?
I did a search and some refer to running “wires” (plural) through the tunnel and some talk about running “a wire”.
I just want to make sure I’m not overlooking something…..
+1 .......... I am in the midst of doing this fuel pump 'wiring' myself ......... where or how did you get the wire past the engine firewall into the tunnel? Did you drill a new hole with a grommet?
yes - that is exactly what I did!
Posted by: scott_in_nh Oct 17 2012, 11:02 AM
There are fibre washers (fiber if you are Amerikan) .. whether they are available or not I can't say.
Part Numbers are:
E 914 201 147 10 (#11)
E 311 201 235 A (#13)
Whether an aluminum or copper crush washer would work I won't address.
If any flexible material was to be used, it should be Viton (Ethanol :puke: added fuels ya know).
viton it is - thanks
Posted by: Kraftwerk Oct 19 2012, 08:45 PM
Hey Scott,
So how did it go?
I might attempt the relocation pretty soon before it gets too cold here.
What did you use for the washers at # 11 & #13?
Did the tank just "lift out" or did you have to disconnect 11 & 13 first?
thanks!
Posted by: Nozzle Oct 20 2012, 07:00 AM
I'm in exactly the same situation, with a complete fuel system refurbish in process. Seems to be a common theme these days. At any rate this is the first time I've tried something like this and I'm using the standard AA fuel pump relocation kit for a stock '73 D-Jet. I have some questions based on replies to this thread:
Why not just run both ground and positive leads from the engine compartment to the steering rack area? The kit I got from AA supplies a combination wire to do this and I'm too much of an electrical novice to know why this isn't recommended here.
Why are the copper crush washers for the supply and return that also came with the kit again not recommended?
Thanks,
John
Posted by: The Cabinetmaker Oct 20 2012, 07:09 AM
the washers for the lines at the tank are available at the Bughaus.com.
Posted by: scott_in_nh Oct 24 2012, 09:17 AM
Hey Scott,
So how did it go?
I might attempt the relocation pretty soon before it gets too cold here.
What did you use for the washers at # 11 & #13?
Did the tank just "lift out" or did you have to disconnect 11 & 13 first?
thanks!
I only had to disconnect the hoses from the tank fittings.
I pulled the fittings from the tank to check the screen and to better aim them where I need them.
If I knew I was going to get sidetracked and the car would still be on stands I would have ordered the correct fiber washers.
The one under the screen I re-used, the one under the return I replaced with a viton washer I made.
I don't have gas in it yet - hopefully it is well sealed!
Getting the fuel lines to and from the two port pump under the steering rack was the hardest part of this project.
In some ways drilling and welding in the sway bar mounts was easier!
I only ran the positive lead through the tunnel, I grounded to the fuel pump mount on the inside under the tank.
Posted by: gothspeed Oct 24 2012, 10:19 AM
Scott, thanks for following up on your progress! I have finally mounted my fuel pump under the steering rack. So far I think I will be running 12v power to the pump from the battery using a relay. The relay will in turn be triggered by the factory harness wires for the orignal fuel pump.
Since I am going with carbs for now, I will be going with the extra ground from the relay panel in the engine compartment.
Did you run fuel pump power with the 'key only' or did you also include an oil pressure switch to control power to the pump? If you included an oil switch in the circuit, how was it done?
I am under the impression the the swtich is open under pressure, which is the opposite of what one would need to complete the circuit.
Posted by: scott_in_nh Oct 27 2012, 07:18 AM
Scott, thanks for following up on your progress! I have finally mounted my fuel pump under the steering rack. So far I think I will be running 12v power to the pump from the battery using a relay. The relay will in turn be triggered by the factory harness wires for the orignal fuel pump.
Since I am going with carbs for now, I will be going with the extra ground from the relay panel in the engine compartment.
Did you run fuel pump power with the 'key only' or did you also include an oil pressure switch to control power to the pump? If you included an oil switch in the circuit, how was it done?
I am under the impression the the swtich is open under pressure, which is the opposite of what one would need to complete the circuit.
I am running D-jet so I am wired to the fuel pump terminal on the relay board.
Posted by: SLITS Oct 27 2012, 07:28 AM
Scott, thanks for following up on your progress! I have finally mounted my fuel pump under the steering rack. So far I think I will be running 12v power to the pump from the battery using a relay. The relay will in turn be triggered by the factory harness wires for the orignal fuel pump.
Since I am going with carbs for now, I will be going with the extra ground from the relay panel in the engine compartment.
Did you run fuel pump power with the 'key only' or did you also include an oil pressure switch to control power to the pump? If you included an oil switch in the circuit, how was it done?
I am under the impression the the swtich is open under pressure, which is the opposite of what one would need to complete the circuit.
It's been a long time, but the switch has contacts for NO and NC. The NC powers the pump while turning the starter. Once the engine fires and you have oil pressure, the NC opens and the NO closes to provide continuous power to the pump.
Posted by: Dave_Darling Oct 27 2012, 11:35 PM
Why not just run both ground and positive leads from the engine compartment to the steering rack area?
That also works. A ground is a ground, so you can run a new ground wire from the old one, or you can just run a wire to any convenient ground. And the chassis itself is a ground, so that can be just about anywhere.
--DD
Posted by: gothspeed Oct 28 2012, 02:36 PM
It's been a long time, but the switch has contacts for NO and NC. The NC powers the pump while turning the starter. Once the engine fires and you have oil pressure, the NC opens and the NO closes to provide continuous power to the pump.
Just to be clear ........... we are talking about the ignition switch that has the NC and NO options correct?
I am running D-jet so I am wired to the fuel pump terminal on the relay board.
OK thanks! I was working on the fuel lines this morning .....
Posted by: scott_in_nh Oct 29 2012, 12:09 PM
So it is on the ground and running again. 
I only had time to take it to the gas sation and back before having to start preparing for the storm.
The shifter still needs a slight adjustment, but I think it is already better then it was.
The console still has to go in once the shifter is done.
The limited cornering I've had indicated a major change with the front bar in!
I don't usually lose parts, but I've misplaced the "buckle" end of one of the gas tank straps, and the car already was missing the strap for the carbon cannister.
If anybody has those parts let me know.
I'll be posting a WTB.
Scott
Posted by: gothspeed Oct 29 2012, 08:33 PM
Drilled some holes and put some grommets in them. Getting ready to route wires, what gauge wire did you use or recommend? I was thinking 16g wire for my cb performance 3.5psi pump. Even though i am using a relay next to the battery, the pump is way up front next to the steering rack. Does anyone see a problem with 16g? Should i go with bigger wire? 
Posted by: SLITS Oct 30 2012, 06:49 AM
Just to be clear ........... we are talking about the ignition switch that has the NC and NO options correct?
I was describing an aftermarket fuel cutoff switch.
Posted by: gothspeed Oct 30 2012, 07:45 AM
I was describing an aftermarket fuel cutoff switch.
What wire gauge do you recommend for a front mounted carter/CB performance 3.5 PSI fuel pump which is powered from the stock battery location?
Posted by: SLITS Oct 30 2012, 10:46 AM
14 or 16 .....
Posted by: gothspeed Oct 30 2012, 11:36 AM
14 or 16 .....
Posted by: 76-914 Oct 30 2012, 11:54 AM
Your fuse needs to match the wire size. The wire size could be anything from 2 ga to 18 ga but if your fuse size doesn't match or is too large then the wire becomes your fuse.
Posted by: gothspeed Oct 30 2012, 12:24 PM
Your fuse needs to match the wire size. The wire size could be anything from 2 ga to 18 ga but if your fuse size doesn't match or is too large then the wire becomes your fuse.
........ here is a chart link for wire gauge to length (below) ......... so installing a fuse a few amps below the ampacity of the wire would work ......... but I am also trying to find out the amp draw of the pump ...... so if possible, I can add an even smaller fuse to further protect the wire circuit.http://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html
Edit: Looks like the Carter/CB Performance 3.5 PSI fuel pump instructions call for a 3 amp fuse and 16 gauge wire. I will run a 14 gauge wire as Slits suggested, so in the future when I go fuel injection (more powerful pump) ...... I should not need to run another wire, only up rate the fuse .......
Thanks to all who have posted info!!
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