So I've been looking at installing an inertia switch for the electric fuel pump cutoff in case of a crash situation. One thing I was concerned about is the sensitivity of these switches. I don't want to launch from the light and trip the switch. Anyone here use these in cars that see the track? Was planning on just using a Ford type switch.
Fuel Pump Inertia Switches
- Thread starter clinteg
- Start date
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Looked into them but really would prefer the inertia switch. And I'm not even certain I could make the oil pressure switch work with my new oil guage plug anyhow.
KitCarlson
Well-Known Member
I would give one a try before wiring it in to see if it passes a few launch tests.
I build in a safety check in my ECU that shuts of coil supply and fuel pump for stalled engine 1/4 of second after engine stops. It works by adding one to a count for each ignition timing sensor signal edge, it is then checked every 1/4 second. If the count has not changed, it cuts the power. Re-start is immediate. It would go along well with the inertia sensor, both together would work for most cases. I have considered making a fuel pump controller that would have more integrated features than any on the market. The liability issues, scare me away. The ones with limited functionality cost $400, and have about $50 worth of parts in them.
I build in a safety check in my ECU that shuts of coil supply and fuel pump for stalled engine 1/4 of second after engine stops. It works by adding one to a count for each ignition timing sensor signal edge, it is then checked every 1/4 second. If the count has not changed, it cuts the power. Re-start is immediate. It would go along well with the inertia sensor, both together would work for most cases. I have considered making a fuel pump controller that would have more integrated features than any on the market. The liability issues, scare me away. The ones with limited functionality cost $400, and have about $50 worth of parts in them.
75DartSE
Well-Known Member
I might have jumped a crown vic cop car before, and it didn't trip the switch, if that helps. Oh ya, the trunk was open and slammed shut upon landing and still didn't trip it, and the switch on those is located in the trunk.
I don't have a running car to try it on or else I would try a launch test. I'm just getting through the wiring now.
The ECU idea sounds all too complicated for and dummy like myself, but it's a really awesome idea.
I'd like to hear the story behind that! Lol!
I went ahead and stopped by Autozone and got a sensor for a Ford Ranger (which I drive daily). I set the switch and moved it around quite a bit trying to set it off and the sensor didn't trip. The only time it would trip is if I banged it against my hand to where it made a sudden change in acceleration. So I'm going to give it a shot and see how it works out.
1968FormulaS340
Well-Known Member
This is why I just switched back to a mechanical pump last weekend.
I've put an oil pressure switch on every electric fuel pump vehicle that I've ever had. Not saying that I add it to an EFI'd vehicle, just to any that I convert. the way that I usually do it to avoid having a plumbing "tree" hanging on the engine is to remote mount it using 1/8" copper tube. I move all of the oil pressure related switches & sensors off the engine.
It's a little buried behind stuff, but here is the chassis mounted end of the system on my '65 Valiant. Fuel pump kill switch under the blower motor and original OP light switch on top of the T. T is mounted via a tab welded to it that picks up the lower blower motor stud. The switch in the control side of the fuel pump relay circuit.
It's a bit messy there at the moment, looking forward to post TBI install being able to tidy up that part of the engine bay.
It's a little buried behind stuff, but here is the chassis mounted end of the system on my '65 Valiant. Fuel pump kill switch under the blower motor and original OP light switch on top of the T. T is mounted via a tab welded to it that picks up the lower blower motor stud. The switch in the control side of the fuel pump relay circuit.
It's a bit messy there at the moment, looking forward to post TBI install being able to tidy up that part of the engine bay.
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