fuel pump cutoff switch question

[fiveohpatrol]

well i think the switch is going bad. a few times i've had to pop the trunk and reset it to start the car. and yesterday leaving a friends house, the thing just fell flat on its face when i floored it and im sure that the switch is at fault.

my question is, can i just jumper it and be fine? i've been told that the flowmasters being so loud and vibrating the car back there could be the reason the switch went bad. is this the case with a lot of cars? because i dont want to replace the switch if its just gonna go bad again soon.

also, i've been thinking about if i jump it, then could i wire in a toggle switch and hide it somewhere as a anti-theft device? or should i do that with the coil or what?

thanks for any help

[chris91LX]

I'm not sure you want to jump that switch. I beleive it's there so the pump won't stay on and spray fuel all over the place if your in an accident. If you want to set up a fuel pump cut off use the relay under the drivers seat. Cut the power wire I think it's the red one (but find out for sure!) and splice a toggle switch to it. Took me more time figuring out where to put the switch than it took me to put it in.

[PKRWUD]

The inertia switch is there for your protection. Removing it is up to you. Relocating it might be a better idea.

Take care,
-Chris

[Rebel79]

You can always replace the switch. Just so you know here is how it works. The inertia switch will allow the fuel pump to operate as long as there is oil pressure. If you flip your car and stall the motor, yet there is a fire, you can increase you chance of dying if the fuel pump was still going. You see the inertia switch will see that the engine has stalled and kill the fuel pump, saving your life. It may be a bit of a pain , but its well worth 3rd degree burns and months in the hospital.

[PKRWUD]

Scott-
I had never heard that explaination before. Where does the ECM get the oil psi input from? My experience with inertia switches had them being impact switches, meaning they are switches that are normally closed, but that become switched open upon a hard impact.

Take care,
-Chris

[fiveohpatrol]

I don't think it has anything to do with the oil pressure. I wish it did though, cause then I wouldnt have had to pull my motor to replace the bearings last year when my oilpump locked up and I drove it thinking it was just the sending unit.

I think I'll just replace it and if it persists then maybe I'll insulate it somehow.

[Rebel79]

Hmm thats how it was explained to me by a top Ford Mechanic. Who knows he has been wrong before.

[fiveohpatrol]

i see you have a 94, was he explaining that for just the SN95's? i bet thats how it works in those

i dunno, maybe not

[PKRWUD]

After doing a little looking, I can't find a Mustang built any year with any engine that has two oil pressure senders, or for that matter, an oil pressure sender that is read by the ECM. They did install an oil level sensor, but it only trips an idiot light. In each case, right through the Cobra 4.6 4V, the inertia switch is a simple impact switch, that is the last switch in line to the fuel pump.

Hmmm.

Take care,
-Chris