Too rich!!

[A1.6HPE]

Hello all,
My integrale has just failed its MOT test for CO2 emissions. I want to weaken the mixture by adjusting the trimmer on the ECU. Does anyone know which way I should rotate it to weaken the mixture?
Planning to set weaker then restore the setting after re-test.

Leo

[chrisc]

You dont want to do that. You want to fix the problem thats causing it to overfuel. If you adjust it to make it run lean for the test, you might end up with it too lean, detonation, and then youll be in a world of pain.

Likely causes of your problem : Lambda probe on exhaust nadgered / Coolant temperature sender nadgered.

[A1.6HPE]

Hello Chris,
It is a simple request - which way to rotate the trimmer?
This is an 8V integrale that does not have a Lambda probe.

Leo

[rossocorsa]

leo not sure which way but I'd be careful with this, if the car fails the emission test, which on non-cat cars is set to a pretty lax standard, I reckon it's a sure sign something is wrong. Also if you happened to damage the potentiometer I understand that the ecu is then scrap :( which is not too good. However IF I can find time I'll climb over the piles of junk (read flavia and beta spares!) and the volumex in the garage and find the relevant workshop manual in the next few days and check what it says assuming no one has answered by then

[A1.6HPE]

Thanks Alan,
I would appreciate that. I realise that fiddling with the adjuster is a recipe for disaster, that is why I don't want to touch befire knowing which way is which. I have a bit of time as two attempts at getting a front suspension ball joint has ended up with one for a 2 wd Delta so at the moment the car is sitting on 3 wheels and a trolley jack. After I got the second ball joint I told the motor factors to throw out the old one, so now am stuck waiting for Chris Bastow to send the proper joint.
The Delta has been chipped and so I think that the mixture may be over-rich, also the car was an absolut pig on the way home so I think that MOT-man leaving it idling all the time didn't help much. When I take it back again I'll leave the radiator fan on manual.

Leo

[rossocorsa]

manuals don't say which way! presumably they assume you have the gear to check it ? you could also (possibly) have an adjuster under the bonnet some dedras have one so delta might have as well.

Sorry that I couldn't help

[A1.6HPE]

Hello Alan,
Oh dear - I'll just have to hope for the best. My guess is anti-clockwise to weaken the mixture.
The engine runs very well and the fuel consumption is pretty good (about 25mpg) so it seems odd that it is too rich - reading was 16% where a pass is 13% or less.

Fingers crossed, Leo

[Pope1]

Hi Leo,

Can't answer your question I'm afraid but I was just wondering whether it would be worth your while to get a Gunson's digital gastester perhaps? They're about 70 UKP and give an indication of the CO content in the exhaust gases. It's a lot to pay for a one-off use but it's not a bad gadget for a Lancia enthusiast to have at his disposal.

[A1.6HPE]

Hello gang,
Well, tweaking the adjuster didn't seem to have much effect! It was set at the halfway point of travel. I turned it about 90 degrees anti-clockwise and the engine ran ok but the revs took a dive when declutching. With it adjusted 90 degrees clockwise it ran as normal. So I set off to MOT-man with it set 90 degrees anticlockwise but with the ecu in the passenger footwell for quick adjustment. The test showed as 11 per cent so beat the 13 per cent mark and got a pass - hooray! Have set the adjuster back to mid-point.
Conclusion? I don't think it made much difference just that on the day the weather and conditions helped. I drove to the test station by country road rather than via the traffic in the town. I reckon that anti-clockwise definitely "leans" the mixture, but not by a huge amount.
However, I am now confident that I can fiddle with the adjuster and restore it to original without any problem. The adjuster "slot" is easliy seen and therefore easy to control. It also seems quite robust.

Leo

[Pope1]

Great stuff Leo. Glad you got it sorted without incident. If only all the gremlins were as easy as that :D .