Dodgy Starting Mk2

[syncro]

It should run OK without the O2 sensor. I tried my syncro with it disconnected and it didn't make much difference. It is only a fine tuning adjustment.

[h100vw]

Yeah the car starts great dead cold and worse as it gets hot.

However, I cant get the lambda out of the manifold.
We tried for ages today, but its up behind the engine near the firewall.
Its welded itself in there with the heat. I even tried a big spanner on the sensor and an engine crane connected to the spanner and it still didnt undo, just lifted the car!!

I`ve already cut the wires as the spanner wouldn`t go over the connector, so I have to change it now. Aaaargh

I`m thinking maybe just put another sensor in a more acessible part of the exhaust.

As for sensors, I have lots of Mk3 ones which have an extra grey wire. Can I use one of these if I omit this wire? There are 2 white wires, how do I know which connects to which?

Get a mk3 manual and see what they are all connected to. The ECU will only need the earth and the signal connected to work but the probe may need power and a separate earth for the heater before the output is any good.

The heater is there so the probe gets to temp quicker, rather than relying on the exhaust gases alone.

I don't think you could get away with out having it connected, I have seen enough bad running G60s in my time to make the statement. They run the same with and without until up to operating temp.

Gavin

[Golf Loon]

The Mk2 sensor has 2 white wires and a black one.

The Mk3 has 2 white, a grey which I think is for heater and a black one.

Does it matter which whites I join together??

[h100vw]

I reckon the whites are for the heater, the grey is probably the earth for the signal and the black the signal. Like a light bulb, I don't think it matters which way round they go.

Gavin

[aussieg60]

I am sure the 2 white wires are 12v for the heater (it shouldnt matter which white gets the 12v as its just a resistor) and the grey should be GND. The black is the signal wire as Gav said. My motor was the same, switched on from cold ok, after heated up it run like crap because the 02 was not earthed. The 4 wire sensors need the grey wire grounded because the ground is crap through the exhaust system.

[Golf Loon]

Right today the friendly exhaust place put a new fitting for the o2 sensor under the car before the cat.

I spliced the 2 whites together, the black to the black and earthed the grey.

Now the car runs **** when cold and ok when its warm. WTF

The black wire where it comes from the car loom has a metal sheath which some genius has earthed to the engine, is this right??

The only thing I can think of is that the white wires need to go onto the opposite wires, or maybe I need a Mk2 sensor.

Any ideas??

[aussieg60]

What do you mean when you spliced the 2 whites together ?

[aussieg60]

I suppose you meant the 2 whites from the loom to the 2 whites on the 02.

[aussieg60]

Ok, I just checked my old engines loom and 02 sensor as its original. If this helps, its like this. From the loom there are 3 wires and a shield.

1. Red/White ----> white 02
2. Black ----> other white on 02
3. Brown/Black ----> black on 02
4. Shield/black insulated ----> should go to a ground on the head cover.

[Golf Loon]

Thanks aussieg60

Now when you say the shield goes to ground on the cover, is this a separate connector?

Yeah I mean I spliced white to white, but does it matter to which one??