106 petrol, failed emissions

[MikeT]

Hi, need to diagnose friends emissions failure. It appears to have a throttle body/carb rather than injectors. Got a lamda sensor too but other than that we're working blind so open to hints and suggestions. CO2 high on idle and 2nd fast idle tests.

The exhaust (incl Cat) was new about 18months ago but if it's an overfuelling problem, that will be junk now anyway and need replacing, right?

[RichardW]

Depends really... Does it look rich, ie, black exhaust, black plugs? Do you have the full read out - if it was rich I would expect Lambda to be off, and HC to be high as well as CO high. If it's just CO high, then it's likely the CAT. You can check whether it's working or not by checking inlet and outlet temps with an IR temp gun - it should be appreciably hotter on the outlet. If you get it on Lexia you might be able to see the output from the Lambda, otherwise you can probe it with an oscilliscope to see what it's doing. How far over is it? A really good thrash, and then present it stinking hot might be enough to get it through.

[CitroJim]

Mike,

Have you popped Pug Planet onto it and run diagnostics? You may find the mixture adjustment has gone out of range..

Also look at live data and check the oxygen sensor is giving the signals it should back to the ECU

I know those well as my daughter used to have a 1.1 206 with Magnetti Marelli Injection...

On hers I used to have to regularly reinitialise and retrain the engine ECU (Pug Planet tells you how and holds your hand) and this used to fix all issues for a while...

If you have not got Planet then Lexia should work if you tell it the car is a Saxo...

[Oldpug]

Those old mono injection 106`s (and Saxo`s) are notorious for this.When they were new Peugeot had a problem with the ECU`s.
I would surgest you find an old school Peugeot/Citroen specialist who has the old "Diag 2000" diagnostic kit to check all the fault codes etc.I've known these to have everything replaced and still fail emissions.Mind you there are a few tricks of the trade to get these past.

[CitroJim]

Pug Planet on a Chinese Lexia 3 always worked OK for me OldfPug...

[MikeT]

Thanks chaps, I couldn't even find a diagnostic socket so didn't got the diag route. Decided to do what we could that didn't cost - spent most of the time cleaning the engine breather pipework, it was choked full of lumpy emulstion and oozing into the carb/injector. Plugs looked very nice considering with a bit of wetness on third plug.

After a good cleanup and italian tune up, went back for a free gas test when, in the right lighting conditions, noticed a slight blue hue to the exhaust - suspect valve stem seals (149,000miles).

[CitroJim]

What did the gas test say then Mike?

[MikeT]

I don't have the fail sheet but IIRC, the CO limit was 0.3 and reading were appx 0.9 idle and 0.5 2nd fast idle. The HC's and lamda also failed horrendously the first but both passed the 2nd. After spotting the blueness, we didn't bother wasting their time on the free gas retest. We'll get the problem sorted first.

[CitroJim]

That's wise Mike.. Blocked breathers may be causing the issue by way of crankcase pressurisation or the breather system may be pulling too much crankcase gas into the inlet tract...

[MikeT]

I have the actual emissions sheet readings now

Fast idle
CO 0.3Limit: 0.597
HC 200Limit: 241
Lambda 0.97-1.03Limit: 1.066

2nd Fast idle
CO 0.3Limit 0.922
HC 200Limit: 152
Lambda 0.97-1.03Limit: 1.024

Natural Idle
CO 0.5Limit: 0.898

I should add that it was a short dirve to the centre, from overnight cold so suspect engine wasn't as hot as it could be.
As I said above, after a thrash up and down the lanes with the plan to retest after cleaning out the breather gunk, there was a hint of blue in the exhaust when revved.

[spider]

I'd agree its worth having half an hour cleaning all the breather pipes out.
Is the air filter reasonably clean ? A dirty filter can raise the HC
It may be worth trying one of the (decent brand!) 'injector cleaners' , I find it best despite the instructions stating a full tank to put one in at 1/4 or less, ultimately fuel tank sizes vary enormously plus you're wanting to see some 'effect' a bit quicker too.

[MikeT]

Yeah, first job was clean the breathers, they were seriously clogged and oozing lumps of emulsion into the throttle body. Noticeable difference after.
Also whipped out the plugs to read - two were whiter than makkes me feel comfortable and one was slightly wet around the threads.

I'll advise Ian (the owner) to get a decent fuel injector cleaner in the meantime.

I was hoping someone might be able "read and translate" the actual emissions readings for further clues. I still find it confusing.