Wiring around oil pressure/fuel pump sending unit
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Junior Member
Joined: Dec 2002
Posts: 77
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From: Indiana, USA
Car: 89 Camaro
Engine: 355
Transmission: Coan rebuilt TH700R-4
Wiring around oil pressure/fuel pump sending unit
I recently put on an auto meter gauge for oil pressure and disconnected the old sending unit and wires. Now, as most of you know the fuel pump stops working. How can I wire around the old sending unit so the fuel pump stays on? I saw someone wired directly to the relay. Is there another way and if not how do I do that? Thanks.
Supreme Member
Joined: Jul 1999
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Is there another way
Won't hurt anything, and then you don't have to hack on your car's wiring. Which by itself wouldn't be so bad, except that if you don't understand what you're doing, you'll end up creating more trouble for yourself in the long term.
Thread Starter
Junior Member
Joined: Dec 2002
Posts: 77
Likes: 1
From: Indiana, USA
Car: 89 Camaro
Engine: 355
Transmission: Coan rebuilt TH700R-4
got it
Ok I figured it out. For those of you that have TBI, take off the fuel pump relay located on the firewall driver side. Take the tan and white wire or known as "A" on the 5 wire harness. Run an ignition wire to that terminal and throw the relay away. When you turn on the key from now on this will turn the pump on.
Thread Starter
Junior Member
Joined: Dec 2002
Posts: 77
Likes: 1
From: Indiana, USA
Car: 89 Camaro
Engine: 355
Transmission: Coan rebuilt TH700R-4
probably because your cars a big piece of Gm factory ****. Splicing wires together doesnt hurt a damn thing. Remove the splice and look there its back to your wonderful GM factory setting. Its alright I am glad its not your car anyway...you wouldnt know what to do with it...let it sit inside all day and stare at it.
Supreme Member
Joined: Jul 1999
Posts: 18,457
Likes: 16
From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Hack
You don't have a clue what you're talking about or how it works, and you're trying to tell me how things should be done.
Go right ahead and hack up your car, won't bother me a bit.
But now that's just one more person I can't be bothered with helping in the future, when you run into some other issue you have no clue about (as the next issue you run into will probably be).
You don't have a clue what you're talking about or how it works, and you're trying to tell me how things should be done.
Go right ahead and hack up your car, won't bother me a bit.
But now that's just one more person I can't be bothered with helping in the future, when you run into some other issue you have no clue about (as the next issue you run into will probably be).
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Thread Starter
Junior Member
Joined: Dec 2002
Posts: 77
Likes: 1
From: Indiana, USA
Car: 89 Camaro
Engine: 355
Transmission: Coan rebuilt TH700R-4
Sure...
Yea, I will come to your over-so-knowing knowledge.... tell me does the fuel pump shut off when your car is running??? Nope....just the same thats going on here. Why don't you try some actual informational replies instead of.....well if it was me i would just wire it back up, or dont install a sound system cause that will blow out your windows. Your a moron that has 0 clue what goes on in a car. At least I found the wire, got it running, and can tell other people what does what now instead of your assumptions. Jack ***.
i think the idea was to shut off the FP when the oil pressure droped below a set point, so as to not allow the engine to self destruct, but you're way to smart for me too so i'll stay out of it.
Thread Starter
Junior Member
Joined: Dec 2002
Posts: 77
Likes: 1
From: Indiana, USA
Car: 89 Camaro
Engine: 355
Transmission: Coan rebuilt TH700R-4
your right..
yes, your right that was the idea behind gm connecting the two together but I have a fuel pressure regulator for my carb. so the fuel is returning to the tank. the problem was i installed the new oil gauge and disconnected the old one. i thought it was unrealiable anyway. so case solved. over and done with.
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Joined: Apr 2003
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From: Bonner Springs, KS
Car: 1995 Corvette
Engine: LT1
Transmission: 6 spd Manual
Axle/Gears: Dana 44, 3:45:1
Re: your right..
Originally posted by ede
i think the idea was to shut off the FP when the oil pressure droped below a set point, so as to not allow the engine to self destruct...
i think the idea was to shut off the FP when the oil pressure droped below a set point, so as to not allow the engine to self destruct...
Originally posted by MustangMuncher
yes, your right that was the idea behind gm connecting the two together but I have a fuel pressure regulator for my carb. so the fuel is returning to the tank.
yes, your right that was the idea behind gm connecting the two together but I have a fuel pressure regulator for my carb. so the fuel is returning to the tank.

I think we can shut this thread down now..
Oh... Hack.
Re: your right..
Originally posted by MustangMuncher
yes, your right that was the idea behind gm connecting the two together but I have a fuel pressure regulator for my carb. so the fuel is returning to the tank. the problem was i installed the new oil gauge and disconnected the old one. i thought it was unrealiable anyway. so case solved. over and done with.
yes, your right that was the idea behind gm connecting the two together but I have a fuel pressure regulator for my carb. so the fuel is returning to the tank. the problem was i installed the new oil gauge and disconnected the old one. i thought it was unrealiable anyway. so case solved. over and done with.
The other nice thing this does is shut off the fuel pump every time the engine dies even if the ignition key is on.
For example, you're in a wreck, fuel lines get severed, with the GM design the pump is stopped. With your HACK the pump will keep right on spraying gas everywhere all over the accident scene.
This is what I was pointing to when I said "Future Darwin award pending" in your other post...first wreck will likely cleanse your genes from the pool.
Last edited by kevinc; Apr 4, 2005 at 04:12 PM.
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From: E.B.F. TN
Car: Tree Huggers
Engine: Do Not
Transmission: Appreciate Me.
-hack-
I never realized installing a 'T' fitting was so difficult.
-hack-
Let me help you with your next mod...
-hack-
Wider is better after all.
-hack-
I need to get something for this.
-hack-
Don't forget to cover your ***...
-hack-
I apologize ahead of time to anyone who drives a taxi.
-hack-
This is as good as using a worm gear clamp and carb fuel line hose to 'fix' cut up fuel tank lines on high pressure FI.
Why do people constanly refuse to do things the right way, then when **** hits the fan, those of us with a minimum+ of common sense have to deal with/pay for their stupidity?
Idiot.
I never realized installing a 'T' fitting was so difficult.-hack-
Let me help you with your next mod...
-hack-
Wider is better after all.
-hack-
I need to get something for this.
-hack-
Don't forget to cover your ***...
-hack-
I apologize ahead of time to anyone who drives a taxi.
-hack-
This is as good as using a worm gear clamp and carb fuel line hose to 'fix' cut up fuel tank lines on high pressure FI.
Why do people constanly refuse to do things the right way, then when **** hits the fan, those of us with a minimum+ of common sense have to deal with/pay for their stupidity?
Idiot.
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Posts: 9,962
Likes: 5
From: Moorestown, NJ
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Actually, the purpose of the sender, on the tbi cars anyway, was to provide backup switched power for the FP should the circuitry in the ecm that controls the fuel pump fail. I never bothered re-installing it in mine since its sort of a moot point, anyway. I do agree that some form of switched power that shuts off with the motor is needed, though.
Joined: Jun 2003
Posts: 5,028
Likes: 78
From: Desert
Car: 1991 Z28 Vert
Engine: 383 single plane efi
Transmission: T-56
Axle/Gears: 8.8 with 3.73s
Yes, and they put it all like that for a reason as stated prior. At least you are keeping the relay, RIGHT?
Member
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From: new york
Car: 91 camaro rs,92 camaro b4c,1983 cam
Engine: 305 tbi Soon To be 500hp 383,l98,ca
Transmission: 700r4,700r4,turbo 400
By that not being connected, would it cause for the car not crank or anything,at all?
Supreme Member
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
If you installed a mechanical meter you really should have removed the oil pressure sending unit near the distributor instead of the oil pressure switch above the oil filter.
I don't know when GM stopped using the oil pressure switch as a safety switch, but my 88' still runs with the switch disconnected, as Vader, and others have have stated the switch is now a fuel pump power back-up source instead of a fuel-pump cutoff, and I'm using an 89' EPROM file, but I don't think that makes a difference.
I don't know when GM stopped using the oil pressure switch as a safety switch, but my 88' still runs with the switch disconnected, as Vader, and others have have stated the switch is now a fuel pump power back-up source instead of a fuel-pump cutoff, and I'm using an 89' EPROM file, but I don't think that makes a difference.
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