Although this is a "traditional" site many of our members use electric fuel pumps as a matter of convenience or, in fact, as a matter of choice. Whatever the reason, we know that an electric fuel pump has a serious problem in that it continues to run IF the ignition key is on! Which means that in the case of an accident, while the engine may not be running, the fuel pump is. Not good! One of the members of my club recently circulated a cure that he found for this problem on the Holley site. Here it is: OIL PRESSURE SAFETY SWITCH Its always a good idea to place a safety switch in the circuit when installing an electric fuel pump. Holley has one available under P/N 12-810. This switch will ensure that the electric pump will not work unless the engine has oil pressure. It will prevent the pump from running in a situation where the motor may stall with the ignition ON. Wiring the switch through the starter solenoid circuit energizes the pump on engine start-up. After the engine is running the switch continues to provide power to the pump as long as there is oil pressure to keep the switch turned on. (SEE ILLUSTRATION) FUEL PRESSURE http://www.holley.com/data/TechService/Technical/Fuel Pump Tech Info.pdf Seems like a small amount of work to gain a great deal of safety. Hope this helps...
Good info. I decided to go for a "crash switch" out of a ford focus. I got 2 from the local junkyard for $10. They're wired in line with the fuel pump and have a bearing that sits inside of a cone. When it's jarred, it breaks the switch and shuts the pump off.. Bonus is that it doesn't require any additional wiring like the oil pressure switch. It's not a huge deal but it was worth it for me to not have to run additional wires.
I also have an inertia switch wired in out of a fox body mustang. if you are hit in the back the switch kicks out and kills the power to the pump even if the engine is still running...
Anybody got a picture? Maybe a part number? If I go to Ford parts, what do I ask the counter man for? Is it really called an inertia switch? That's the coolest idea yet for the electric pump. There's enough fuel in the float bowls to build oil pressure. I need one of these widgets!!
If using both, the ideal fuel pump switch would be a double throw one with a momentary ON one way that bypasses the oil pressure switch for use to prime the carb, the other pole a normal ON that feeds through the safety devices. The second switch system could of course just be feed via ignition switch.
I've had a oil pressure switch in the fuel pump circuit for years...had to replace it a few times too, it's kind of close to the header and cooks and starts to leak after a while. Also it died once, contacts quit working, somewhere in texas. I used the old Monza pressure switch, it's a stock replacement part, although for an older vehicle so it's not so easy to find anymore. Three terminals, marked I S P for ignition, starter, pump.
you can still get an oil pressure switch for thirdgen camaro or firebird at any auto parts store for $5. the ford switch in the trunk is cool except for when you drive over a speed bump,pot hole or somthing that accidently triggers the switch and end up in a dead car a couple miles down the road confused as to why the car died lol. that has happened a couple times to my younger sister with her fox mustang. some day ill get her to figure out she needs to check that switch/button before calling me to rescue her lol.
Its called an inertia switch, and is found in the right kickpanels of Ford trucks, trunks of Mustangs and most cars. Great idea from Ford, and have a very low failure rate. Made by Lucas, believe it or not! Use it inline of the fuel pump relay, don't run full pump amperage thru it
usually they're called a fuel pump inertia switch. You could go to the dealer but you're going to get raped on it. Like i said, snag one from a junked ford. You can buy them aftermarket from a couple places, I can't remember who though.
Yup, exactly why I stuck a stock mechanical in the flathead. I had been running gravity feed and even had an electric pump. But between pre-start pressurization and oil pressure cut-off, it just seemed like too much hassle.
Here's the one that summit has. Mine doesn't look exactly like this but you get the idea. http://www.summitracing.com/parts/SUM-890145/
Good Idea, One way to do this is wire a relay to feed power to the fuel pump, that way the "oil" switch can control the relay as well as a momentary switch for priming.
the one I use is a 3 terminal, it sends power to the pump while cranking....which is kind of helpful....
Many racing associations require a rollover switch if you run an electric pump. You can wire them to kill the ignition along with the pump. The units from various Fords are popular. They are usually found behind the side panel in the trunk...5 bucks at many wrecking yards.
I posted this before but I will again, A lot of import cars have a module behind the dash that reads the ignition coil, if the engine stops, the pump turns off, they are easy to wire and probably cost almost nothing at the yards. normally four wires, ground, power in, power to the pump, and a wire that goes to the negative side of the coil. the advantage is they are quicker then the oil pressure switch, with the former pressure has to bleed off the switch, and the contacts could short in a wreck,these others are inside of the car, completely electronic, so no contacts to short out. got one in an import now that's 25 years old,still works fine. they have been in use since the 70's. I do think i'm going to add an inertia switch with a bypass somewhere near the drivers seat. the problem with an inertia switch,is if someone wants to steal your car, all they have to do is bump it and wait. ever wonder why the cops sometimes bump a fleeing car first?
Ford inertia cut-out, part number F5AB-9341-AA A lot cheaper at your local pick a part (look in the right side of the trunk behind the panel) or I have a few, PM me.
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