944 turbo oxygen sensor ( lambda sensor )

[aprotogerellis]

Hi there,

It seems like my 944 turbo (951) '86 needs a new oxygen sensor (failing emissions).

I've looked at the manuals for the 944 (non-turbo) and the lambda seems to be easily accessible underneath the car at the point where the 2 exhaust pipes join up (after the 4 from the engine have become 2...).

I've tried to find it on my turbo but no luck at all! So two questions:

1) Do all turbos have an oxygen sensor? Mine was first sold in Germany and is the 85-86 model.

2) Where in the world can I find it? Do I need to remove anything in order to get to it?

Thanks a lot!
Alex

 

[944Turbo]

In the vertical pipes beneath the turbo, from underneath - it may be next to impossible to undo plus gas or other penetrating oil may help,
Tony

 

[944Turbo]

PS if your car has the emmisions test tube on the exhaust manifold side of the engine - might only be later cars - when the cap on top was split on mine it failed the emmisions test,
Tony

 

[aprotogerellis]

Thanks guys,

I will give it a go tomorrow...

Do you know whether I need to remove any components to reach it?

Thanks,
Alex

 

[aprotogerellis]

Ok, now I know why I couldn't find the sensor... my car doesn't have one! The whole in the exhaust pipe that is meant to hold it is plugged. (see the pics). Unless I'm looking at the wrong place that is...

The question is whether there is meant to be one there in the first place.

Its an 85/86 944 turbo, bought from Germany.

Does anyone know whether it is meant to have one and, if it does, where it is meant to be plugged into?

Many thanks!

 

[Fen]

I was going to say before it might not have had one. In the UK it wouldn't have had one for sure at that age and I wasn't sure if Germany had them at all, as an option (possibly standard with a delete option) or it was compulsory there in 1986.

 

[944Turbo]

Yes sorry unless it has a catalytic convertor it wont have one, (89 ish on in the UK) and could be deleted,
Tony

 

[John Sims]

Beaky didn't have one and we tried to undo the plug to fit one.......

In the end we bought a replacement cross over pipe from a car that had a Lambda. The blanking plug wasn't coming out no matter what.

I may still have the plugged cross over if you want to try to get it out.

 

[aprotogerellis]

Thanks guys...

I'm starting to get a bit worried about the emissions then. If the airflow meter works fine (I tested it using the clarks-garage guide) and there is no need for an oxygen sensor then what else could be wrong?

944turbo, you said the below a few days ago, I'm not quite sure where to find the test tube and what it looks like (if I have one). Could you please give me some pointers?

PS if your car has the emmisions test tube on the exhaust manifold side of the engine - might only be later cars - when the cap on top was split on mine it failed the emmisions test,

Many thanks!

 

[944Turbo]

I think it might apply only to cat equipped cars - mine was originally, the tube runs up from the exhaust manifold from just in front of the split to the wastegate and up to the top of the engine. It is then capped with a rubber seal brown or blue.

Otherwise,

There is a mixture adjustment screw on the AFM, it only has limited range.

Is it standard or modified?

If you move the throttle cam (where the accelerator cable ends) off its stop with the engine off can you hear a click?

Is your fuel pressure correct?

Are the seals intact around the fuel injectors? (drop a little oil around where they enter the manifold and listen for changes)

Are the rotor arm / distributor cap / leads and plugs in good condition - what colour are the plugs?

 

[aprotogerellis]

Yup, definitelly doesn't and never had an oxygen sensor.

The CO2 is reading around 7% so the AFM adjustment is unlikely to take down enough (I think you can adjust it by about +-2%).

The car is 100% standard so nothing strange there. I'll check all the ther bits and get back to you. I think the most likely problem now is a leak somewhere... I'll do a fair bit of WD40 spraying and see what happens).

 

[aprotogerellis]

Ok, a month later and no closer to the goal!

The problem still stands... CO is too high. But now I've tests:
- Air flow meter: both the gate and the temperature sensor work
- Cylinder head temp sensor: No problem
- O2 sensor: doesn't exist (and never did)
- Throttle position switch: works fine
- Injector leaks: none I can find

So I'm getting pretty stuck on what may be the problem... the two potentials I think are:
- Fuel pressure (any idea how to test?)
- Faulty/dirty injectors

Any other ideas?

 

[sawood12]

How is the guy testing your emissions? For a non-Lambda non-cat car it should be at idle but for a cat equipped car it should be a 4krpm. Your MOT tester isn't testing your car at 4krpm is he? If it is at idle then you have to adjust the screw on your AFM. Once you depress the throttle and the TPS switch is not pressed in then you are running off your ECU maps therefore have no adjustment.

You could also look for splits in your J-boot or vaccum leaks.