9 replies to this topic

[ClassicAsh]

Ok my code reader got delivered today which I purchased from FlyingScot (many thanks) It showed up a few things straight away, number one was that the intake air temp sensor cct fault came up, I had replaced the sensor so thought hmm, but on inspection it was actually the wire to the sensor that was damaged, so I have repaired that, cleared the fault and all is well.

 

 I then decided to run through the  component test. I have a reading on the lambda of 0.8v and this does not deviate at all, in the book that came with the code reader is says in limp home mode the ECU substitutes a reading of 0.8 volts, hence running the car rich, so  can I assume that the Lambda sensor is duff? I know I fitted a new one when I rebuilt the engine manifold etc, but it was a cheap replacement part. and not a bosch one, I am going to try the old bosch Lambda sensor and see if that works, if not looks like a new one is needed. I just wanted to be advised with the reading I have that the sensor is duff?

 

mini cooper spi. 1995 model.

 

any advice

 

thanks

[edkirk30]

You can manually check the lambda values with a multimeter if you're suspicious of the ECU. As you've probably read the voltage should rise and fall periodically. More details on this pinned post:

 

http://www.theminifo...-oxygen-sensor/

[ClassicAsh]

so swapped the lambda sensor for the old bosch one, at first it fluctuated between 0,1v and 1,2 volts, but once the engine was up to temp it didn't even register on the reader, 0.0v and if revved to approx. 200orpm again showing nothing 0.0v. I am confused !

[ClassicAsh]

anyone know where I can buy a genuine bosch lambda scensor ?

 

thanks

[FlyingScot]

Minispares used to sell them but you can buy from a Bosch Centre (google for one near you) part number 0258 003 193 or a vehicle parts place. Just check it a genuine one, the cheap ones are no good IMHO.
Also check the voltage to it - it has four wires 2 for output but 2 supply the internal heater when the motor is cold, the yellow tyco relay works this (you can test it with your ACR too - you will hear it click)

FS

[FlyingScot]

Land Rover used them in the Freelander and early Discos too from memory so might be worth a try if you have a local LR dealer nearby ? The part number on a landie has a L added, the Rover part is MHK10004. But like most stuff this part number is used generically to cover compatible parts unfortunately.

FS

[ClassicAsh]

Thanks for the reply's I found one on eBay in the end, genuine one, £52, which wasn't to bad, bloody typical though, I thought I would run through the tests with the code reader and the old original bosch one fitted and hey presto it is operating correctly, not sure why it wasn't yesterday but its all good today, looks like I will have a spare lambda sensor now. I know I wont ever buy a cheap pattern one again though.

 

thanks all

[tmsmini]

I would keep an eye on the relay to the sensor heater. I wasn't sure if the ACR allowed this test on the SPi, but as FS says it does. The heater should only be needed for a few minutes as after that the exhaust is hot enough for the sensor to work on its own. Also the wiring harness to the sensor, sometimes people creatively rewire/reroute and put stress on the harness. And after 20 years wire insulation does get brittle and can crack.

Terry

[FlyingScot]

 IMG_0660.JPG   37.11K   12 downloads

Number 7 Terry O2 heater. You're right about the wiring, in fact most of the issues I come across with SPi and MPi are just "mini wiring" issues - bad earths, poor or bodged connectors, corrosion or heat embrittlement.

FS

Edited by FlyingScot, 29 March 2017 - 02:44 PM.

[tmsmini]

Here is an example of the wires becoming brittle as well as the insulation. This one was hidden by the rubber boot.

Attached Files

•  DSC_0272a.jpg   45.46K   8 downloads