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Tell me how to bypass the oil pressure sender

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Old Nov 20, 2017 | 10:58 AM
  #1  
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Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Tell me how to bypass the oil pressure sender

It's a 92' 5.0 TPI. Oil pressure sender located right above the oil filter.

Here's the situation. Somehow the electrical connector to the sender roasted on the exhaust and won't work anymore. The car can't see the oil pressure and thus cuts the fuel pump off from working. I know the car has oil pressure as I'm running a sender for my Speedhut gauge from the port on the back china wall. The car is my daily and I need to get it running NOW and can't wait the 1-2 weeks for a replacement pigtail connector.

I know you can bypass the sender by doing some searching on here but no one tells me sepcifically how to do it. What wires can I splice at the fuel pump relay to get the dame fuel pump to run? Please help.
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Old Nov 20, 2017 | 11:55 AM
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Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Tell me how to bypass the oil pressure sender

Connect the orange wire to the gray, iirc those are the colors blue or tan would be for the dash gauge or light.

Last edited by Tuned Performance; Nov 20, 2017 at 11:58 AM.
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Old Nov 20, 2017 | 11:58 AM
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Re: Tell me how to bypass the oil pressure sender

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Old Nov 20, 2017 | 12:03 PM
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Car: 1967 Camaro, 91 z28
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Axle/Gears: J65 pbr on stock posi 10bolt
Re: Tell me how to bypass the oil pressure sender

If you try to bypass it the pump will run all the time. You would need to run accessory power to the grey wire.
The grey wire is also located at the pump relay so you can tap it there. It might work if you took the pink wire of the ignition coil and ran a wire off it to the grey wire at the pump relay.
http://tpiparts.net/inc/sdetail/4342/3995

Last edited by Tuned Performance; Nov 20, 2017 at 12:07 PM.
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Old Nov 20, 2017 | 02:28 PM
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Re: Tell me how to bypass the oil pressure sender

According to that diagram, and what I thought to begin with, the switch portion of the oil pressure sender doesn't actually do anything unless the relay fails. It is just a bypass for a bad relay as far as I can tell.
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Old Nov 20, 2017 | 02:51 PM
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Re: Tell me how to bypass the oil pressure sender



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Old Nov 20, 2017 | 03:01 PM
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Car: 87 Formula, 91 Trans Am
Engine: 355 tpi, 305tpi
Transmission: 700r4, 700r4
Re: Tell me how to bypass the oil pressure sender

The oil pressure switch and fuel pump relay are run parallel, NOT in series. They do not have an affect on each other. If one or the other goes bad it is inconsequential. If they both go bad, which seems likely in your case, the pump gets no power. Replace the relay, then fix the plug when you get it.
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Old Nov 22, 2017 | 11:43 AM
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From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Re: Tell me how to bypass the oil pressure sender

OK, I've replaced the relay and I have the pigtail on it's way. But a question... If what you say is true, and they run parallel and not in line, then logically if the Oil Pressure sender was left unpluged, the fuel pump would still get power from the relay and the only thing lost would be the function of the stock gauge. But this isn't the case, I tried and the car still won't start. Why is that?
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Old Nov 22, 2017 | 01:38 PM
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Re: Tell me how to bypass the oil pressure sender

Originally Posted by MeenZ28
But this isn't the case, I tried and the car still won't start. Why is that?
Does the fuel pump run and provide fuel pressure at the rail?

RBob.
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Old Nov 22, 2017 | 01:47 PM
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From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Re: Tell me how to bypass the oil pressure sender

Originally Posted by RBob
Does the fuel pump run and provide fuel pressure at the rail?

RBob.
No. It doesn't come on at all. No prime, no fuel pressure at the rails (checked with a gauge). I know the pump is good as I tried jumping the terminals at the relay and it comes on and shows fuel pressure. This makes me think they do infact run in series... otherwise what else could cause the fuel pump to "sleep" without the oil pressure sender hooked up?

Last edited by MeenZ28; Nov 22, 2017 at 01:50 PM.
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Old Nov 22, 2017 | 03:19 PM
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From: Raymond, Wi
Car: 87 Formula, 91 Trans Am
Engine: 355 tpi, 305tpi
Transmission: 700r4, 700r4
Re: Tell me how to bypass the oil pressure sender

Did one of the wires on the connector melt and short the circuit?? Look at your fuel pump fuse.
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Old Nov 23, 2017 | 08:53 AM
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From: Chasing Electrons
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Re: Tell me how to bypass the oil pressure sender

Originally Posted by MeenZ28
No. It doesn't come on at all. No prime, no fuel pressure at the rails (checked with a gauge). I know the pump is good as I tried jumping the terminals at the relay and it comes on and shows fuel pressure. This makes me think they do infact run in series... otherwise what else could cause the fuel pump to "sleep" without the oil pressure sender hooked up?
With this testing (jumped the relay connections), and you have replaced the relay that leaves the ECM. It provides power to the relay coil to energize it. The other end of the coil is run to a ground.

RBob.
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