Fuel pump inertia switch

@Gordon Nichols posted:

I have an electric fuel pump but nothing to automatically shut it off in the event of a crash.  After seeing that Alan Merklin includes an inertial cut-off switch in his builds, I decided to add one to Pearl to bring her in to the 21’st century (be still, my heart).  The switch I bought was mid-priced, from Amazon:  

https://www.amazon.com/gp/aw/d...pop_mob_b_asin_title

It looks as good as others out there, and comes with a matching connector but absolutely ZERO installation or operational instructions(!!!)

I’ll be figuring out how it works and how to configure and install it as temps allow over the next week.  If enough are interested, I can post the install progress on here and what I find along the way (The first thing I found is that I did such a great job of burying the fuel pump wire in the front wiring harness that I can’t find it!!)

If anyone else has been considering this, let me know if you’re interested and I’ll post my progress.  

Gordon

I found this in the reviews it may save you some time ....

Its wired for NO and yet it's really wired NC. With the switch not depressed (active) it is wired NO. That is why the factory has it wired incorrectly. It's not easy to move the wire over as indicated, take your time .

Yup, I found that link, too.  Kind of weird that you have to look up Youtube videos and forum posts to find out how the heck to configure and install the thing.  I’ve already modded the pigtail connector to get it to a Normally Closed version for my pump, and in the process, pushed on the orange cap to see what would happen and it changed state to normally open with no way to reset it!!!!  

I freaked out!  

Pushing the button again did Bupka.  Panic ensued…..

Then,  I tried all sorts of things, short of taking it apart, to reset it back to NC until finally, in desperation, I tapped it against the desk and POOF!  It went back to it’s original state.  Whew!

Then, of course, I had to play with it by pressing the button and then slapping it around a few times, just to see what happens until I figured out that there is a metal ball inside that pushes against a trigger in a crash, causing the switch to open up, like when the car rolls over.  

I still don’t know if it wants to be mounted straight up or on an angle or what, but that will become evident as I go along and research it a bit more.  In the meantime, I’ve got a few gas gauge dampeners to build.

I used this controller on my car.  It looks for a signal from the tach and only powers the pump when the engine is running.  It will run for about 3 seconds when first powered up by the key.  I usually turn my key on/off a couple of times prior to starting in order to fill the carb bowls.

However, the inertia switch is a good idea in the case where you have an accident and the engine continues to run.   Now I am thinking that maybe I should have both!   Or is that just overkill?  (I'm pretty good at overkill)

I dunno. If my car has the greasy side up, I think it'll likely be a situation where I don't care too much if the fuel pump is running. The fuel pickup is on the bottom of the tank anyhow.

Hi. UK guy here. I ended up with an electric fuel pump (not by choice but by desperation of the mechanic trying get it to run smoother) It was worse than that, needed a rebuild due to cracked valve seats. I wasn't happy with the electric fuel pump and the same worry of "in a crash and fuel pump still working" I used a unit from a peugeot 205 (little french car) In my case it was easy to install as I'd already installed a remote cut off switch - via mobile - which meant I'd already dug out the fuel pump power line. That unit needed to be straight up.

@Stan Galat posted:

I dunno. If my car has the greasy side up, I think it'll likely be a situation where I don't care too much if the fuel pump is running. The fuel pickup is on the bottom of the tank anyhow.

Viking funeral!

I installed my inertia switch in the frunk, on the bulkhead where I also have my fuse/relay panel.  Really easy place to mount it and it looks like it belongs there.

But I got about half way through installing everything and running new wires for it the existing harnesses and asked myself "Why the hell am I doing all of this?"

I should have listened to Stan and just left well enough alone.

If the car is upside down enough to make that switch toggle, I'll probably be dead, anyway.