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considering a fuel cut relay using the fuel pump relay

but where the hell is it, wassit look like exactly ?

part number ? not one of those common 056 700 5260 12V 22W relays is it ?

What do you mean by fuel cut?

Its under the dash mounted on a bracket near the ecu i think

A small metal can.

Why not put a switch in the line of the fuel pump instead of looking for the relay?

I realise this will have load bearing current running through it but you should beable to get a switch to match it I'd imagine..

Cheers

Bennie

Ah i get it, like an imobiliser.

Use a DPDT switch.

Two centre teminals to the ecu, two terminals on one side to the fuel pump relay and the other two terminals on the other side to a resistor equivalent to that of the relay

relay is located under the drivers dash behind the fuse panel. its one of 4 relays on a panel. it will have a HEAVY blue wire on it. that will chase to the rear of the car.

I've just been looking through the 87 workshop manual and I think you can achieve what you want more easily by cutting power in a more accessable place .

The manual shows that there are 4 fusible links above and slightly behind the ignition coil . No1 FL feeds the fuel pump relay/ignition relay/MPFI control unit/injector dropping resistor (injector power supply) .

If you can make the power feed open circuit then it can't start .

A cheeky one would be to isolate the crank angle sensors speed output signal as the engine will crank all day and not inject any fuel .

Ways and means .

very cheeky. though it will set a code on the computer. the other idea I like..

There's another reason to cut power to the fuel pump. In the event of an accident, cutting fuel pump power can be important and some cars fit an inertia switch to do this. I considered having a magnetic switch in the circuit at one stage. In the event of an accident, the magnet would slide off the switch - no fuel flow. At other times, moving the magnet to another location would achieve the same result - no fuel.

Our cars are designed so that as soon as the engine stops/stalls, the fuel pump stops to prevent the flow of fuel in an accident.

I like Disco's idea, but easier would be to place the imobiliser switch on the supply to the coil or the injector resistor pack.

I like Disco's idea, but easier would be to place the imobiliser switch on the supply to the coil or the injector resistor pack.

I had an insurance company insist I fit an immobiliser about 10 years ago. You had to touch a hidden point on the car whilst starting for it to work. Damn thing became dangerous - it would cut in from time to time and the car would just stop.

Suparoo wrote:Our cars are designed so that as soon as the engine stops/stalls, the fuel pump stops to prevent the flow of fuel in an accident.

Sometimes stopping the engine is the problem. There's a system that operates in a way that once the engine stops the fuel pump does the same...

My MPFI before i got it was in a rollover and the guy was unable to get to the key to turn it off. The engine kept running and ended up seizing up due to lack of oil... Lucky for me it was the big end bearings that did all the heating and seizing, so the main bearing carriers were in good condition for new bearings...

Cheers

Bennie

OK , thanks for the info and ideas guys (I just HATE getting upside down, twisted and contorted up there under the dash) meanwhile the ALDI steering wheel lock should be a good deterrent (statistically). The CAS disconnect is a good one , but aint got one !!

The resistors would be to stop throwing error codes ?? YEP ?? I'd cheat there not knowing what Ohms to use - and switch it to another relay with just its earth connected switching nothing.