Advice on VR6 lambda probe wiring.

[aclwalker 3]

Hi all,

 

I recently replaced my lambda sensor on my 1994 VR6 and it made an incredible difference to the running of the car. There was no fault code with the probe but my mileage is high (199k) and I reckoned it hadn't been changed for ages. My car has never driven as well as it did after this repair. It was incredible.

 

However, I had a bit of difficulty in fitting it, and shortly after the replacement, problems returned and codes started to now appear in VAG-COM about a faulty lambda probe.

 

Basically, the probe that was in originally was a Ford one (I've got a photo of it somewhere I could maybe upload) and all 4 wires were spliced onto a piece of cable with the connector on it (presumably from the previous probe). It really was a mess. However the main problem was that on the engine side connector, the 4th wire (the one that sits alone) was broken and so the 4 way connector had been bypassed for this 4th wire.

 

I was forced to cut the same wire on my new probe and I decided to connect it with crimps (possibly a bad idea), and tape it all up with electrical tape. I didn't press the crimps hard enough the first time, and the second time I think I pressed too hard and broke the strands. I've now done it for a third time (last night) and I'm not sure this repair will last. I soldered the wire onto the crimp as well this time for extra security.

 

I found http://www.lambdapower.co.uk/diagnosis/diagnostic_index.asp, and right down the bottom it describes what each wire is. It would seem that the broken one (it sits on its own) is the signal wire, with the one next to it being earth and the two others being the heater.

 

The wires going to the engine side connector look slightly strange. There's a three core cable from which two of the wires (signal and earth) come from (the third core is simply cut and not connected to anything) while the two heater wires come from somewhere else. Is this normal? I suspect that some of the wiring may have been replaced in the past. It just doesn't look original.

 

Is there any better way of doing this than crimps, such that I can disconnect it in future? I didn't fancy soldering it permanently in case there's a problem later on.

 

Also, is it possible to buy the engine side harness such that I no longer have a broken wire? I'm also missing the rubber hood that covers the connector, so I'm worried about water ingress, although I've taped it all up as best I could.

 

The car is running great again, but I'm worried it will simply deteriorate over the next week or so again. I'm running out of wire with which to make these connections too, hence the desire to replace the engine side harness if possible.

 

Thanks.

[Supercharged 2]

Hi there - best thing to do is to buy the plug and some repair wires from VW, cut it back and re-solder with at least a double insulating of heatshrink, also make sure the earth on the probe side of the wiring is good!

[aclwalker 3]

Hi, thanks for the reply.

 

Are these repair wires already attached to the plug? Unfortunately I was forced to cut the wire on the probe (which was brand new) itself in order to connect to the broken wire on the engine-side connector. Your suggestion sounds a good long term solution.

 

It looks like somebody has messed around with the wiring before though, as the signal wires come from a 3 core cable (with the third core unused) while the heater ones come from somewhere else.

 

Thanks