Fuel Cutoff Switch

[Av8ferg]

Hey guys, surfing the web today I stumbled on two different recent incidents where guys 280z’s caught on fire.  This is almost never a concern on a new car but older cars have a much higher probability.  
I keep a fire extinguisher in my car for good reason but was wondering if a fuel cutoff switch would be a good idea.  
It could serve two purposes.  Both an anti theft device and a way to shutdown fuel to the engine immediately if there was a secondary failure.  Not sure if it worth it or not.  Only found one post on the subject on the forum that was posted in 2007. 

 

 

Edited May 22, 2023 by Av8ferg

[SteveJ]

You could install one without too much trouble. Just intercept the fuel pump wire here.

That connector is on the driver's side under the dash. The green/blue is the fuel pump positive.

Here are the parts I suggest:

1. 14 gauge wire (green would be good.
2. 2 of these connectors: http://www.vintageconnections.com/Products/Detail/78 You only need 1, but you may need an extra male terminal.
3. A switch. I would go with a 20A switch like this: https://www.amazon.com/dp/B0BGX6Z3Y1

Back the terminal for the green/blue out of the 6 pin connector with a small jeweler's screwdriver. Put that terminal in one of the connectors you bought.

Assemble the switch in this order: female connector - wire - switch - wire - male terminal into the 6 pin connector where the green/blue wire was.

When the switch is on, the fuel pump has power. When the switch is off, you killed fuel pump power.

 

[Zed Head]

Your 77 should already have one in the AFM.  When air flow stops the fuel pump power is cut off.  Your fuel pump should not be running when you turn the key on.  Only at Start and when the engine is running.

That first picture shows a modified engine, with individual coils.  It must have aftermarket engine management.

 

But, on the topic, if you haven't already done it - the 1978 and 280ZX fuel rails are safer than the three piece 75-77 rails.  The hose connecting the three pieces can leak.  That first picture shows what's probably a 78 rail.  One piece metal.

[Patcon]

The burnt engine is a turbo setup. I believe you can see an intercooler pipe behind the radiator. Also modified like Zed mentioned. Lots of ways to loght that car with a hot turbo right under the fuel system and near the brake fluid reservoirs. Especially if the tune was a little lean.

The red car has the vented hood. Would be nice to know whats under the hood there. How old is that picture?

I might can find it at Copart or IAAI

[Yarb]

@SteveJThanks brother, just what I need for my project. Should have everything in a couple of days.

[SteveJ]

6 minutes ago, Yarb said:

@SteveJThanks brother, just what I need for my project. Should have everything in a couple of days.

@Yarb For your project, I would advise doing it differently. You'll want a different connector and an inertia switch, too. I'll send you a PM when I get home and can get all of the part numbers/sources.

[Av8ferg]

Thanks SteveJ! I’ll get to work on that.

I know on my 77 that the fuel pump should only be running when the engine is running or on start but it would be nice to have an alternate means of cutting the fuel if for whatever reason is this system fails, and to stop potential thieves. You gotta remember what I do for a living. We have triple redundant safety and operational systems on most areas of aircraft.
Short story: When the F-35 engineers came out to the ship while we’re were doing operational flying (Harriers). We had hours of conversation with them about the new F-35 design (this was 2003 timeframe so early in design stage). They had no plan to put a backup generator for emergency electrical power or an standby attitude gyro). The engineers comment when we quested those decisions was “you won’t need them because the primary generator, engine and Inertial Nav Sys will never fail.” The laughter in the room amongst the pilots was deafening. 20 years later the F-35 has all those redundant systems except it still has only one engine . The engine that was never going to fail has already led to several crashes of a $150 million aircraft. I love engineers but they aren’t the one that have to operate the machines they design.

I already have the 78 fuel rail on my car because is used less hoses.

[Yarb]

@av8ferg might have parts I don’t need according to @stevej. My original order is in transit. Bargain time/trading material😂😂😂

[Zed Head]

The manufacturers are running out of names.  "Hmknana"

[Barefootdan]

I ran one on mine when I redid my wiring. Definitely not intended for theft as I labeled my switch FUEL  But I do enjoy having it. I also want to look into inertia switches in case of a crash and I am unable to shut off my fuel manually. 

[SteveJ]

Inertia switch: https://www.amazon.com/gp/product/B07RBK4873

The only catch is that you have to re-pin the switch because they put it on normally open contacts. It's relatively easy to change.

[Zed Head]

Most Ford vehicles have inertia switches.  If you want a high volume auto factory made piece.  No offense to the Amazon parts but I'd rather have a used (by time only) Ford part than an untested part.  Typically behind the kick panel on the passenger side.  The red button is visible so that it can be reset.  Salvage yards would have hundreds.