sheltonw3

the car I am working on is a 91' V6, every time I turnoff the key, the fuel pump keeps running, I replaced the relay, it still runs, so now I have to disconnect the + cable each time the car is turned off, even my fan keeps running, not getting anywhere right now, I tried running a By-pass, but after running for 25 minutes, the inline switch melted, I am thinking it might be a different relay, since there are 3 of them in one place on the drivers side, or a faulty ECM?

TTOP350

iTrader: (8)

Is the oil psi switch a 3 wire on those or 1 wire?

sheltonw3

It's a standard 3 wire.

TTOP350

iTrader: (8)

Next time it happens, unplug the oil psi switch. If it stops, the internal switch in there is bad. If it stays running, the relay is bad.

sheltonw3

I just had the oil sending unit replaced, and even replaced the relay, but on the drivers side fire wall, there are 3 relay, I replaced what should have been the fuel pump relay, but now I wonder if they are out of place?...I'll try unplugging each one to see what is defective next.

sheltonw3

Where would the Enternal switch be just incase?

RBob

iTrader: (1)

On a '91 V6 the fuel pump relay has a short red wire with a fast-on connector on the end. See if you can tell which relay that goes to, it will be the fuel pump relay.

Since you also state that the fan runs too, it sounds like someone did some re-wiring. As the fan relay coil loses power at key-off. At least in a stock configuration.

RBob.

sheltonw3

The fan was never rewired, it just kicked on and only stays on when the car is in use, so it might be a shot relay there too???

sheltonw3

It's raining outside now, but I did notice a loose red wire connector that is not plugged in, could that be the culprit?

Tuned Performance

iTrader: (92)

I think rbob is referring to the wire you can power up the relay. This pigtail is for testing the relay iirc.
This is a way to identify the fp relay from the other relays.

sheltonw3

I went to unplug all 3 relays, the fuel pump still ran, while the car was off, so I am lost as to what should be done next?

Tuned Performance

iTrader: (92)

The fp can only get power through the relay or ops. Sounds like you have a wiring issue since you just replaced the ops.

sheltonw3

what would happen if I unplugged the Oils ending unit?...would the car still run?

Tuned Performance

iTrader: (92)

Yes, the ops is backup if the relay fails.

sheltonw3

still stuck, the sun light is gone, just gonna wait til tomorrow and try to see whats happening and then trouble shoot my problem?

sheltonw3

A few things I am just now realizing, 1. my key only now turns forward and not back to ACC to use the radio only, 2. I wonder if the new oil sending unit is defective? 3. where is this so called (off switch) located for the fuel pump?....going nuts here*

sheltonw3

I just looked again and noticed the oil sending unit lock tab is broken off, would that cause a problem?

TTOP350

iTrader: (8)

Sounds like you may have an issue with the ign switch or lock cyl.
Which could be the problem.

There is no "off" switch for the fuel pump that you can turn off with a button or lever. The switch I'm referring to is inside the oil psi sending unit. I have had a couple fail and keep the fuel pump running. Even when the relay shuts off correctly.

sheltonw3

Great!...1st thing to do is swap the Oil sending unit, trouble shoot from there, then play around with replacing the Key Lock cylinder*

sheltonw3

Well, tried replacing the Oil sending pig tail, still got the same result of it running, but I realized I had bought a single wire after market sending unit several months ago and found it, so when it gets dry enough, I will put that in and do a rewire and if all goes well, the pump should only come on when the key is turned* >>>Fingers Crossed<<<