What about a Crash Relay for Electric Fuel Pump

[Bihili]

I was reading http://www.mooregoodink.com/news/overnight-success-for-electrical-wizard-after-40-years-of-toil/
and also saw this http://www.summitracing.com/parts/rfw-cr92
and thought it to be a good idea but my fuel pump is already on a separate relay.

I know Ford has had something like this for many years on their vehicles.

Seems like I could create the same thing for less money but I wanted to hear you opinions.

[chevynut]

I've heard of a "rollover switch" to shut off the fuel pump, but not a "crash relay".

[Bihili]

The Ron Francis switch must be an inertia switch.
Here is their install instructions:
http://www.ronfrancis.com/images/CR92-INST.pdf

[chevynut]

It's an inertial switch. Go here and look at install instructions...

http://www.ronfrancis.com/prodinfo.asp?number=CR-92

[Bihili]

Maybe it contains this:
http://www.dimensionengineering.com/info/accelerometers

[chevynut]

My bet is it's less sophisticated than that.

http://www.ebay.com/itm/JAGUAR-S-TYPE-IMPACT-SENSOR-BUTTON-SWITCH-IGNITION-CRASH-1L2T-9341-AC-/220721333882

[chevynut]

Looks like you could build your own for about $25 in parts instead of paying RF $112. I just bought the Jag sensor for $15 and a relay is $5 (already have some). I think this is a pretty good idea so I'll probably put one under my rear seat.

http://www.ebay.com/sch/i.html?_odkw=JAGUAR++IMPACT+SENSOR+-side+-airbag&_sop=15&_from=R40|R40|R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0&_nkw=1L2T-9341-AC&_sacat=0
(http://www.ebay.com/sch/i.html?_odkw=JAGUAR++IMPACT+SENSOR+-side+-airbag&_sop=15&_from=R40|R40|R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0&_nkw=1L2T-9341-AC&_sacat=0)

Thanks for the idea!

[chevynut]

Another thing to add to my "options" list. Crash sensor fuel pump shutoff. :)

[Bihili]

Well I found a Ford crash sensor and pigtail so I am thinking of mounting it in the trunk.
I assume the red reset button needs to be pointed up.

[markm]

Another thing to add to my "options" list. Crash sensor fuel pump shutoff. :)

Complicated stuff I don't need or want on a hot rod.

[chevynut]

Complicated stuff I don't need or want on a hot rod.

Complicated? It's a simple little inertial switch that turns a relay to the pump off. Lots of new cars have one for safety reasons and I hope mine is never activated. If it has the potential to prevent my car from completely burning up, it's going in.

But I suppose you're still running a carburetor with a mechanical fuel pump that OEMs abandoned almost 3 decades ago in favor of a much better fuel delivery system. EFI used to be an "option", now you can't even buy a car with a carb.

[chevynut]

thought it to be a good idea but my fuel pump is already on a separate relay.

You should be able to wire the crash switch into your current relay. Just put it in series with the coil of the relay....all it is is a contactor so when the pump is running it's like it's not even there. No need to even add another relay, imo. Let me know if you can think of a reason this won't work.

Ron Francis says to put his setup "close to the pump". I don't see why or how that helps. The pump wire goes from the pump relay to the pump in any case. I think I'm going to put mine under the console with all the other electrical stuff, and close to my pump relay.

[markm]

Anyone can run a simgle carburetor it takes more talent to run multiple one like I do.

[Rick_L]

Let's see a photo of the talent meter and then prove it's yours, LOL.

[Bihili]

You should be able to wire the crash switch into your current relay. Just put it in series with the coil of the relay....all it is is a contactor so when the pump is running it's like it's not even there.

When I read the Ron Francis instructions it says: the crash sensor is connected to the ground wire of the relay.
Would you agree with that?

[chevynut]

When I read the Ron Francis instructions it says: the crash sensor is connected to the ground wire of the relay.
Would you agree with that?

I don't see why it makes any difference which side of the relay coil it's on. All it does is break the circuit to disengage the relay. Either way the same small current runs through it.

[chevynut]

Well I found a Ford crash sensor and pigtail so I am thinking of mounting it in the trunk.
I assume the red reset button needs to be pointed up.

Yup, mine says "Ford" on it too. But I didn't get the pigtail with it. What kind of connector is it? It has big contact pins so it looks to me like it could be used without a relay. Also, it has 3 pins...what's the third one for? Maybe an indicator light?

[chevynut]

http://ww2.justanswer.com/uploads/ebrock63/2010-10-12_012858_2010-10-12_192547.png

[Bihili]

The eBay crash sensor switch arrived. Made by Ford.
Mine has a two wire pigtail and the device looks fairly simple.
Tap the device and the reset button pops up.
Sounds like a round ball rattling around on the inside after it is tripped.

I am planning to install near the existing fuel pump relay with the reset button pointing up.

Mine came from a cheaper car (Festiva) so probably did not have a dash light therefore only two wires.

[chevynut]

I was wondering what one of these things would do with a jolt from a hard shift. Are you going to put it in the power wire or the relay coil wire? I think it would work fine either place.

Do you have a pic of the connector? I should have thought about the pigtail.

[Bihili]

Do you have a pic of the connector?

http://i686.photobucket.com/albums/vv226/bihili57/Mobile%20Uploads/2015-02/20150215_114832.jpg (http://s686.photobucket.com/user/bihili57/media/Mobile%20Uploads/2015-02/20150215_114832.jpg.html)

http://i686.photobucket.com/albums/vv226/bihili57/Mobile%20Uploads/2015-02/20150215_114902.jpg (http://s686.photobucket.com/user/bihili57/media/Mobile%20Uploads/2015-02/20150215_114902.jpg.html)
Mine has three pins also but only two wires.

[chevynut]

Thanks Bill, that looks like the connector I need. Why in the hell do they use custom connectors there? Any part numbers on it?

[WagonCrazy]

This has been a very informative thread to follow. Timely for me as I continue with my LS1 Nomad build.

Nobody chimed in on your question: “I was wondering what one of these things would do with a jolt from a hard shift”

Obviously, including this sensor switch makes all the sense in the world...in a collision where the fuel line has been breached, but the 12volt power has NOT shut down. Fires get going real fast with an open fuel line spewing fuel out...

But I too wondered how sensitive to movement this sensor would be. What a giant PITA to have to reset this thing all the time when shifting hard, driving hard, launching, etc.

Guess the only way to know is to install it and then find out later on. Could always remove it from the system, but that doesn’t do anything for ones sense of preserving their car from a total fire after an accident...

[chevynut]

Paul, I don't know if there's any specs on the acceleration that would cause one of these things to trigger, or if there's different kinds of them. It seems like mine triggers fairly easily when hitting my hand with it. However, that is probably a very high acceleration event like a hard collision. My gut tells me that a hard shift isn't going to trigger one of these (I was just kinda thinking out loud). Even if it does, it's easy to disable it by bypassing it if it becomes a problem. I'm installing mine, and we'll see what happens. I think it's a good, inexpensive safety device that we hope we never need.