Fault code reading- 1997 940 HPT.

[Bugjam1999]

Quick follow up- I took the lambda sensor out and it was garbage, rattled when I shook it and it was possible to see bits of broken porcelain looking in through the slots in it. Replaced it with a Bosch one and the car runs much better now

Then this week the idle was all over the place, fluctuating between 950 where it should be and 1200. Took the idle air control valve out but left it plugged into the system and used mode three in the diagnostic system- this mode cycles through running the cooling fan, firing the injectors, cycling the idle air control valve and some other things. Sprayed wd-40 on the idle air control valve as it was cycling, then replaced it- car idles perfectly at 950rpm now

One last thing, I put the check engine light in a dash blank so I'll know if there are any codes to read - none right now

[TonyS9]

Does the light mean there are codes? I thought it was just mixture issues.

Not sure if there are still problems with my 940 turbo transplant into 360, but no lambda showing. Its working, comes on with ignition, using the choke light.

[Bugjam1999]

The light should come on (so you know it's working) when you put the key in and turn it to position 2. It should then go out when the engine starts. If the light remains on when the engine is running, then there are codes to be read.

There are various codes, all of which will cause the light to remain on, some of which refer to the lambda sensor and some of which refer to the mixture. As its only a singular light you'll need to build a code reader (which is really easy) to read the codes and see which fault has been highlighted.

[tonymuse]

Hello GPL1968
How are you?
Are you UK based?
I very much like your Home built Diagnostic Flash Code Reader.
Would you be at all interested in making one for me please?
I would be happy for you to put a price to that and will pay you up front.

Electrics lose me completely

I would be very grateful to you. Feel free to email me tonymuse@btinternetcom
I do hope you might be interested in my little proposal

Best wishes
Tony

[rogerthechorister]

Curiously (despite my contributions here earlier) I am not finding the build diagram. Has anyone still got it in pictorial form please?

I am having fun (not) with one of my Sport Editions. Running too rich.

CO at fast idle - 1.12% but max allowed is 0.3
CO at second fast idle - 1.0 - max allowed 0.3
CO at natural idle - 0.93 - max allowed 0.5.

If I am using the reader correctly I think I should be using pin 3 - but that won't tell me what is causing the over-richness, will it?

I have done the basics - new lambda sensor, new air filter, new distributor cap and rotor arm and new HT leads and plugs - loadsamoney but I wanted to do them anyway. Oh and a bottle of stuff I was given called Cataclean. Not much improvement.

So I am open to ideas what to do next - possibles would be the IAC - I do not know how to do that - the AMM (I have a spare) and either or both of the temperature senders under the inlet manifold.

I have MoT thanks to tester who insanely assumed I had no cat and no EGR - why he thought that on a '96 I have no idea. So its not really urgent, but I want to get it sorted before it DOES become urgent.

[Rversteeg]

Forget abut the IAC. The only thing it does is letting combustion air bypass the throttle housing. The effect is the same as if you would slightly open the throttle plate manually. You could check the switch on the throttle shaft. It tells the ECU if the gas pedal is pushed or not, although I am not sure if this does anything to the mixture control.
Also forget about the temperature sensor for the temp gauge (not sure if it the front or rear one). It only serves the temp gauge, nothing else.

[rogerthechorister]

I am told that the temp sensor for the ECU is the one nearest the bulkhead.

[griston64]

Originally Posted by rogerthechorister

I am told that the temp sensor for the ECU is the one nearest the bulkhead.

That is correct. If thats failed it will be hard to start from cold and possibly even harder to start when warm

[griston64]

Originally Posted by rogerthechorister

Curiously (despite my contributions here earlier) I am not finding the build diagram. Has anyone still got it in pictorial form please?

I am having fun (not) with one of my Sport Editions. Running too rich.

CO at fast idle - 1.12% but max allowed is 0.3
CO at second fast idle - 1.0 - max allowed 0.3
CO at natural idle - 0.93 - max allowed 0.5.

If I am using the reader correctly I think I should be using pin 3 - but that won't tell me what is causing the over-richness, will it?

I have done the basics - new lambda sensor, new air filter, new distributor cap and rotor arm and new HT leads and plugs - loadsamoney but I wanted to do them anyway. Oh and a bottle of stuff I was given called Cataclean. Not much improvement.

So I am open to ideas what to do next - possibles would be the IAC - I do not know how to do that - the AMM (I have a spare) and either or both of the temperature senders under the inlet manifold.

I have MoT thanks to tester who insanely assumed I had no cat and no EGR - why he thought that on a '96 I have no idea. So its not really urgent, but I want to get it sorted before it DOES become urgent.

Out of curiosity what Lambda sensor did you fit ? Although if it was running that rich before and still after it's possibly not that

[TonyS9]

If the systems are working correctly then you must have a fuel, air or exhaust leak somewhere.

How about checking the injectors for leaks?

You must be getting a good mixture signal from the O2 sensor if the lambda light isn't lighting.

What about an exhaust leak putting the O2 sensor off?