furyus2
Well-Known Member
Hey, I'm wiring up a fuel pump relay. Battery is up front. Pump is in the back. Where do I mount the relay? Up front by the battery, or back by the pump? I think up front, but would like others input. Thanks.
Fuel pump relay location
- Thread starter furyus2
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67Dart273
Well-Known Member
Does not matter. Main thing is that the wiring to the relay contacts is fused close to the source and large enough for pump current. Same with wire from relay to pump
Keep in mind "this is a good time" to think about oil pressure and or crash switch, and or a security (anti theft) switch in the coil (trigger) circuit
Also keep in mind many replacement relays are not particularly water resistant, so underhood "splash" might be a problem
Also check the relay coil for protection diodes. The "Bosch" copy / look alike relays seem to come both ways. If you hook the coil up reversed, you create a dead short
The way this one is wired, pin 86 MUST be positive, and 85 must be ground
http://www.bcae1.com/images/jpegs/IMG_7451b.jpg
Keep in mind "this is a good time" to think about oil pressure and or crash switch, and or a security (anti theft) switch in the coil (trigger) circuit
Also keep in mind many replacement relays are not particularly water resistant, so underhood "splash" might be a problem
Also check the relay coil for protection diodes. The "Bosch" copy / look alike relays seem to come both ways. If you hook the coil up reversed, you create a dead short
The way this one is wired, pin 86 MUST be positive, and 85 must be ground
http://www.bcae1.com/images/jpegs/IMG_7451b.jpg
please wire in one of these http://www.ebay.ca/itm/Land-Rover-D...ash=item2ee7b9adc4:g:td4AAOSwFnFWCad2&vxp=mtr
for your safety new cars have these for a reason and its law in my province .
I put my relay and inertia switch under my centre console in my duster .
for your safety new cars have these for a reason and its law in my province .
I put my relay and inertia switch under my centre console in my duster .
furyus2
Well-Known Member
Thanks for the replies. I got the Summit fuel pump relay kit. Has good directions. I just wasn't sure about location. I will find a weather resistant location, and I plan on wiring it through the oil pressure sending unit. I might have to order the one from summit. It comes with a circuit breaker, and I plan to use a fuse and switch to the 12v switched wire. I plan on using an inertia switch. Does it get wired into the wire to the pump, ground, or where?
Relays should be close to the item it controls.
blown71duster
Well-Known Member
I would place the inertia switch in series of fuel power feed and place it somewhere accessible ,behind kick panel would be a good spot ,could mount the relay next to it .Then you only have one wire to run back to the rear.
67Dart273
Well-Known Member
Actually Ron it doesn't matter. Wire size from source to load is most important. Most these new cars (all?) have rear/ tank mount pumps and the relays way up front
Mine (relay) "will" be in the back if I live long enough, but that's where both the pump and battery will be.
I use the enertia switch out of a 2000 and up Ford. the junkyards are full of them, just look in the trunk.
Enertia switches must be wired into the control side of the relay. They are not rated to handle pump current.
Enertia switches must be wired into the control side of the relay. They are not rated to handle pump current.
67Dart273
Well-Known Member
That resembles the Ranger switch. I almost mentioned them. Since you've evidently seen these "in native" how do you see them mounted? The Rangers are mounted to the firewall, just like in the photo, button "up" and connector down, vertically.
furyus2
Well-Known Member
So, for those of us who aren't that smart with wiring, would that be the lighter gauge switched power wire? Is it wired by just cutting the relay wire, and wiring it one side in, one out?
67Dart273
Well-Known Member
Exactly. You can also hide a toggle switch or other switch somewhere and use it for anti -theft.....if "they" can't turn on the fuel pump, "they" aren't driving your car very far.
69_340_GTS
Well-Known Member
I put the circuit breaker and the relay under the back seat. Out of sight, protected from the weather, and close to the pump.
blown71duster
Well-Known Member
They are wired in series with the power wire in every one I have ever seen. That is one thing I like about fords ,It makes it nice to hook a scope up to and check out the fuel pump on the feed wire.
Here is a schematic of a 2000 Ford :
67Dart273
Well-Known Member
Sorry completely unreadable. What you need to do is upload that in a larger format to someplace like Photobucket and then post a link
blown71duster
Well-Known Member
Try this one:
You are correct about the Fords wiring the enertia switch into the pump power wire. What I should have said was some after market fuel pumps pull more current than a stock Ford and I've never known what the max current rating is for the switch, so I wire them into the control side.
blown71duster
Well-Known Member
I suggested what most OEM use, which is an Inertia switch in the Kick panel or in the trunk area wired in-line with the power feed of the relay. The Inertia switch is capable of a 20 amp circuit which is good to handle most any high performance fuel pump. You would just have to check the rating of the fuel pump you are running. OEM isn't putting Inertia switches in the trunk area and running control side wiring back there , plus pump feed wiring for a reason, just not needed.
You can get a High performance pump that pulls less than 15 amps good for over 700hp, So you just need to check what your pump uses.
http://realstreetperformance.com/Fuel-Pump-Comparison-Test.html
furyus2
Well-Known Member
So, if I wire the switched wire from the relay, to the inertia switch, to the kill switch, to oil pressure switch, to fused source, isn't that a lot to ask of the one wire? I bought a 30 amp switch, and the circuit breaker from battery is 30 amps.can I wire the switch into the battery wire?
67Dart273
Well-Known Member
I would wire all the "controls" into the trigger wire. "Too much?" Not if done properly.
Let's look at "one wire" in the factory setup.............your left rear turn bulb. "What all" is in that train?
Battery......starter relay.......bulkhead connector.........ammeter.........ignition switch........fuse panel (through the fuse)........to the turn signal flasher...........to the turn signal switch........to the left kick panel connector.........."all the way" to the rear.......to the left rear turn bulb.
This, really, is no different. You need each wire and each connection to be dependable and reliable. You need the wire dressed / tied up "safe" away from mechanical / heat etc damage.
I may or may not put an oil pressure switch in mind, but I certainly am installing a "crash" switch. And, LOL, I may change my mind on the oil switch.
My anti theft device is a switch behind the ashtray that will only run the pump if it is open.
It may not matter where the relay is located, however, it's a lot easier to troubleshoot if it's close to the item it supports. I'd place the inertia switch right next to the relay. FYI, if the car ever leaves the line violently, inertia switches will sometimes pop.
The basic idea for relays is to take load off switches, etc. No need for a 30 amp switch to trigger a relay. A typical tyco/bosch relay draws under .5 amps.
You have to run a power supply wire back there anyways, what's the issue running a 16-20ga trigger wire?
The oil pressure shut off should not be carrying the power supply, it should likely be in the trigger circuit side.
The basic idea for relays is to take load off switches, etc. No need for a 30 amp switch to trigger a relay. A typical tyco/bosch relay draws under .5 amps.
You have to run a power supply wire back there anyways, what's the issue running a 16-20ga trigger wire?
The oil pressure shut off should not be carrying the power supply, it should likely be in the trigger circuit side.
furyus2
Well-Known Member
Thanks guys. Your opinions have been more than helpful. The relay directions say to mount the circuit breaker as close to power supply as possible, so I put it next to the starter relay. I plan on mounting the pump relay and inertia switch above the driver's side kick panel. Then ground to the relay mount. This will leave only the single pump wire to run to the back of the car. Any thoughts on this, let me know.
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