FYI FORD MustangSteve's Ford Mustang Forum / fuel inerta switch or oil PS

**Posted by Cab4word67** 7/18/2024 11:40 AM

Hello again, I know that with my Sniper system I have a elecric fuel pump with 60psi. I know I should/need to install a saftey switch. Im looking at the Inerta switch like I heard Nos861 installed and wonder if that is a better route than tapping into my oil line and wireing a pressure switch with a relay?
Any input would be apprciated

**Posted by rpm** 7/18/2024 12:11 PM

Do both. They are not mutually exclusive.

**Posted by MS** 7/18/2024 1:16 PM

The inertia switch is device that kills the car’s power and engine in the event of a crash. The oil pressure switch is a device that kills the fuel supply in the event the engine loses oil pressure.

In my mind, these are not related to each other. One is to avoid fuel leakage and fire. One is to protect the engine from damage if you have an oil related failure.

Of course, there could be some overlap in a triggering event, but seems like the inertia switch protects everything.

The only bad part is trying to remember you have one after you hit a huge pothole and the car shuts down.

**Posted by Nos681** 7/18/2024 11:01 PM

Factory Ford EFI uses a relay, inertia switch, and then fuel pump.

Keep it simple.

I have a factory Ford inertia switch mounted on gas filler support bracket and have never had a problem on Michigan’s potholed roads.

**Posted by BobE** 7/19/2024 6:30 AM

I have the inertia switch installed as per Nos681 installation. And I’ve also not had the pump shutoff due to NY potholes, and bad roads.

**Posted by Bullet Bob** 7/19/2024 8:24 AM

If your aftermarket EFI system does not shut down the fuel pump on loss of rpm, as does the Ford EEC system, then you probably should install an oil pressure switch to supervise the FP relay. The trunk mounted inertia switch is a given. You do NOT want any electric fuel pump to keep running after a collision.

**Posted by Cab4word67** 7/19/2024 9:24 AM

OK sounds like we will do both and then test out the oregon pot hole roads too.

**Posted by Bullet Bob** 7/19/2024 11:46 AM

Takes a pretty good smack to trip the inertia switch. Drove the Heap to Lincoln NE back in May on I70, I76, and I80, all fine examples of current highway maintenence. Never tripped the switch once.
BB1.

**Posted by Nos681** 7/19/2024 2:36 PM

I know Ford Rangers had the inertia switch mounted in the kick panel area up high near glove box.
Fairly easy to get to.

Foxbody Mustang (1992) was rear center under all trim pieces in hatchback.

New Edge (2000/2001) convertibles were near driver rear tail light under trim.u

Last edited by Nos681 (7/19/2024 2:40 PM)

**Posted by MS** 7/19/2024 4:51 PM

I did not mean to imply a pothole would trip the switch. My point was that I hoped I remembered to think of the existence of the switch years later after a “triggering event”.

**Posted by TKOPerformance** 7/20/2024 4:40 PM

Mount the switch away from where it can get accidentally tripped. I've seen it happen a couple time son Ford Rangers which had them on the firewall high in the passenger's footwell area (though apparently not high enough).

For the oil pressure switch the only thing that would concern me would be what would happen if the switch failed while driving, causing the car to shut down. Factory systems I believe would only "look" at that switch on start up.to avoid such a situation.