Bit of engine loom that doesn't connect to anything...

[AlpineCab]

Seem to have a piece of the loom in the engine bay that doesn't actually do anything? The Engine is M20 2.0L cat-ready on a Jan 1989 cab.

The Loom runs from a relay above the n/s front arch, under inlet manifold to a connector near the water temp sensors, and it also includes a resistor wired into it. There is also a bit of the loom (single wire) that runs from relay to the starter motor.

Is this part of the cat ready bit of the loom, and as it doesn't (seem) to plug into anything can it be taken out?

[Brianmoooore]

Don't recognize this one. The relay position for the oxygen sensor is one of the three on the nearside wing,- others are main DME and fuel pump relays. The connector for the oxygen sensor is a four pin socket clipped under the battery tray.
Does the wire look factory fitted?

[Emotechnik]

Seem to have a piece of the loom in the engine bay that doesn't actually do anything? The Engine is M20 2.0L cat-ready on a Jan 1989 cab.

The Loom runs from a relay above the n/s front arch, under inlet manifold to a connector near the water temp sensors, and it also includes a resistor wired into it. There is also a bit of the loom (single wire) that runs from relay to the starter motor.

Is this part of the cat ready bit of the loom, and as it doesn't (seem) to plug into anything can it be taken out?

That'll be a hesitant start mod', this was a factory approved mod' that dealers fitted to help with reluctant starting problems on high mileage/carbon'd up cars, not such a problem now with high detergent fuels.

HISTORY; When carbon has built up on the rear of the inlet valves the initial injection pulses of fuel just soak into the carbon and not enough fuel reaches the cylinder, hence a long cranking/start cycle.

The connection from the starter closes the relay and brings the resistor in to play, thereby fooling the coolant sensor to think it is actually colder and thereby injecting more fuel to compensate for the amount that is being soaked up by the carbon.

The plug connection up by the temp sensor was just "piggy-back-connected" between the origional loom and coolant sensor.

When a car is decoked the connection can be removed.

If your car runs OK I would leave it alone.

If you fancy an experiment and maybe more power/higher fuel consumption, you could try reconnecting it to the sensor and operate the starter wire to the relay through a switch, when you throw the switch the resistor comes into play and you get more fuel being injected.

This is in a similar vain to the Ebay multi-fit performance increase resistor mods.

[AlpineCab]

Brianmoooore - Wire is definitely factory fit, and the relay is in the same place you descibe for the oxygen sensor.

Emotechnik - exactly as you describe!

I have actually had the whole loom isolated out of the circuit for some months now, and so I'm going to bin it today. To be honest, car seems to start / run better without it!

Thanks guys, I've been trying to suss this one for ages. I'd been looking at every single picture I could find of M20 engines to see if anyone else had one!