electric fuel pump and oil pressure kill switch

saylor

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get a 12v 30A relay napa#AR279SB or any other relay. bosch is popular. i had one laying around. it can be 4 or 5 prong. we dont use the prong in the middle, so its all good.

get an oil pressure cut off / kill switch. napa#A68301. there are others out there too, get a 3 prong switch with (S)tarter (I)gnition and (P)ump connections.

get a spool of 10AWG stranded wire. dont get solid core wire. my car is 18' long so i got two spools...

get a box of wire terminal connectors. you need 7 to connect the switch and relay. You also need some fork or loop connectors for your GND and + wires.

Get a (depending on pump amps) 5A inline fuse. With the relay we are going to dedicate power to the pump so it doesnt have to draw off some other thing.

A bit of teflon tape for the brass threads at the oil pressure hookup.

1/8" Brass T and extension tube from lowes plumbing section.

i extended off my existing oil pressure gauge hookup spot on the top rear of the block by the firewall. I got a brass T and a 6" long 1/8" male/male brass tube. the bottom of the T with 6" extension goes to block, one side goes back to my regular oil gauge, and the other side is where the pressure kill switch is.

switch:
(S) = i wired to starter solenoid. This will run the pump when you are cranking.
(I) = i wired this to the heater fuse in the fuse box. Something that comes on only when the key is turned and you are driving down the road.
(P) = this is going to go to the relay #86
 
relays are pretty much the same, they may be labeled differently. get a 30A 12v relay.
usually they are labeled 30,85,86,87,87a
the napa one is E,F,D,A,C.
some are 1,3,4,2,5.
same thing.

30 = 5A fused power from BATT + (better fuse it with that inline fuse!)
85 = GND
86 = from (P)ump at oil pressure kill switch.
87 = power run to fuel pump
 
what you end up with is the fuel pump will run at starting (S to P, P kicks the relay on)
and at operation (kill switch has oil pressure, I to P, P kicks the relay on)
If you lose oil pressure, I to P opens and stops the pump.
The relay allows us to give the pump direct 5A power from the battery, so we dont have a 5A draw on some other thing like AC or heater fuse or wherever you hook (I) up to. All we need is enough juice to throw the relay.
 
oil-pressure-kill-switch.jpgoil pressure kill switch and brass T fitting

oil-pressure-kill-switch.jpg
 
fp-relay.jpg fuel pump relay. I have it upside down to show wiring so I could jump #30 and #87 together with a piece wire and run the pump from here.

fp-relay.jpg
 
mrGasket12SFP.jpg I went with a Mr Gasket #12S pump. 4-7PSI, like 35gpm or something. No regulator at carb - don't think ill need it at this PSI at this length of run of line.

mrGasket12SFP.jpg
 
I had to come back to this post today . . .

I fried my fuel pump. it had a decent long life, and its my fault, so...

after my car sits all week, I have to prime it up with gas. so I jumper wire the FP relay and run it until it fills up everything. then I start the car.

so I made a switch that was 30 <> 87 thru an on/off switch so I could run the pump from a switch instead of a piece of jumper wire @ the relay.

primed up, got motor running, shut off my new primer switch, all good.

got about to the end of the alley and the FP quit. pushed it home :/ heavy asss car.

now thinking about it, jumping 30 <> 87 is not the way to do this. I think I basically bypassed the relay.

I think the next step is to hit power to 86 via the switch, activating the relay. let the relay relay.

$50 electrical lesson. and a lot of sweat and cussing.

try not to die -

- saylor
 
Yes, you bypassed the relay completely.

To power the relay and in turn, power the pump, you could jump (or install a switch) from 30 to 86.
 
Bypassing the relay will have zero effect on fuel pump longevity.

It died because it was time.

Kevin

im goin with this :)

it would have blown the fuse if something was wrong, right?

:)

anyways I got the new pump in ,everything tight and dry, spun it around the block, and parked it. too fkn hot. I don't know how hot it was today, but damn it was hot.
 
I have the same pump, still have the mechanical pump on the block and fittings/line i the trunk. Just to be safe
 
http://www.gmcmhphotos.com/photos/data/6603/medium/Electric_Pump_Choke.jpg

a picture of whats doin. breddy handey.

so i took my fans and instead of running them on/off with a 160* temperature switch threaded into the water pump housing, i ran them to (I) on this oil kill switch so the fans go on/off same as the fuel pump now controlled by oil pressure.

then i used (P) to run my new electric choke on the 750 eddie i got.

if you look at the switch face / tongs so that the odd pin is on the right side; the top pin is (P) 86 relay, odd pin is (S) starter, and the bottom pin is (I) ignition.

try not to die -

- saylor
 
I have the same pump, still have the mechanical pump on the block and fittings/line i the trunk. Just to be safe
+1

this pic is for furyus67 - he wanted to see whats doin at the T -

20200703_102820.jpg

if you think of a capital letter T, I have the T on its head / upside down. left arm has a 6" threaded brass tube extended down to the oil hole in the top rear block back by the transmission. right arm of the T under the wireloom, is the P/S/I oil pressure kill switch. The stem of the T | is what you see with the Teflon tape and brass tube going upwards and out to the interior cabin wheres my cheap oil pressure gauge. Take the plastic tube that comes with the oil pressure gauge and throw it in the trash and then go buy 25' roll of tube and swap that out.

after revisiting this post - this has been one of the better upgrades I've done. Having a primer switch in-cabin is money on cold or hot starts, and fuel pressure or vapor lock issues will never happen.


for all you kids out there against electric fuel pumps - heres why its better than a mechanical.
Go get a vanilla shake. A really thick one, like your mom. That's your gas tank. The shake is.
Put a straw in the shake. That's your fuel line.
Now suck like mad. (LOL). that's your mechanical fuel pump.
the straw collapses and no shake comes out.
Next, remove the straw from the shake and blow thru the straw (LOL more). No straw collapse, shake inside the straw leaves rapidly from straw all over everything.


try not to die -

- saylor
 
Dumb question. Can this setup be used with the factory oil pressure sender, using the factory oil pressure gauge, and not using an aftermarket oil pressure gauge?

I'm trying to figure it out based on the pictures of how mine looked before I took it out.
Can I not put the same sender in - or is that what the P/S/I oil pressure kill switch is replacing.

IMG_20190929_082952_LI.jpg
IMG_20190929_083022_LI.jpg
 
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