5 replies to this topic

[Big_Adam]

Evening.

So due to massive paranoia and the fact I always think I'm going to bust my car I wish to add two relays to control the positive of the coil and the fuel pump. So I turn on car, flick switch and turn the key all the way it starts. If the switch is on, no coil power or fuel pump rendering the car useless.

Are there any major concerns I should have about doing this?

As in will the coil explode or similar?

Was going to add the switch / relay between the fuse box and coil, fuel pump relay will be between fuse box and pump. The swtich I was planning to use is the old rear window heater one (don't have a rear window heater ... thing but I have the switch), is that going to be okay for this?

Should I stick two relays in parallel or in sequence?

Thought it best to ask before hand, that and the weather might be better on Friday so I'd like to get bits ordered today (was going to go with 15amp wire).

Ta for info.

[Ethel]

So it's a security idea?

You could run both the pump & ignition off one relay.

One potential problem is that you'd have to remember to switch it off when you park up & there's always the chance it would be switched unintentionally.

You could rig up something similar to the Turbo fuel pump circuit that uses the oil pressure switch to control the solenoid, slightly adapted to use the brake test switch instead of the starter to energise it. You'd also gain the intended safety fuel cut feature.

http://www.eraturbo....l/technical.htm

I'm sure you'll find other immobiliser products & plans with a google and check out ignition kill switches which would be more of a challenge to a hotwiring toerag: earth the -ve side of the coil and it will stop the distributor making sparks.

[Big_Adam]

So it's a security idea?

You could run both the pump & ignition off one relay.

One potential problem is that you'd have to remember to switch it off when you park up & there's always the chance it would be switched unintentionally.

I wanted to use two relays (one for each thing, coil on one, pump on other) connected to the rear heater / demister switch so when the ignition is off the car is off.

Not sure about the oil pressure whatsit, its moving to an area of wiring magic I'm not good with. That and my oil pressure will really drop after a long drive at idle.

[Bungle]

You could rig up something similar to the Turbo fuel pump circuit that uses the oil pressure switch to control the solenoid, slightly adapted to use the brake test switch instead of the starter to energise it. You'd also gain the intended safety fuel cut feature.

it's a good idea to do something like this to the fuel pump anyway, if you crash your mini you want the pump to stop rather than pumping fuel everywhere

[Big_Adam]

You could rig up something similar to the Turbo fuel pump circuit that uses the oil pressure switch to control the solenoid, slightly adapted to use the brake test switch instead of the starter to energise it. You'd also gain the intended safety fuel cut feature.

it's a good idea to do something like this to the fuel pump anyway, if you crash your mini you want the pump to stop rather than pumping fuel everywhere

My cars 40years old and mad mostly of patches and rust. If I crash, fuel and fire will be the least of my concerns. But you do make a good point, I had a look and someone linked to a bump sensor or something similar (have a knock, fuel cuts off) would wiring that in-line work?

Edited by Big_Adam, 17 November 2010 - 01:27 PM.

[Ethel]

It isn't as complicated as you may think, the oil pressure just opens a switch to put the light out, it would operate a relay just as easily - just use one that breaks the circuit instead of making it. All you need is a means of doing the same until the oil warning light goes out.


You mean an inertia switch. Yes, plenty in the scrappers, just splice it in, in series.