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[BigAl]

I have the timing relay for 95 ron with cat and the engine has the flat spot we all know of. I then put on the timing relay for 95 ron with no cat and the engine is smooth and a lot more responsive.

In the manual it says that if you change the ECU or AFM that you need to recalibrate the AFM idle mixture. To do this it says disconnect the Lambda sensor and adjust the mixture screw until correct emissions are achieved. The manual also says that when fitted with a Lambda sensor that the mixture screw has no effect, hence taking off the Lambda sensor.

Instead of disconnecting the Lambda sensor, can I just use the timing relay for 95 ron with no cat to adjust the mixture via the idle mixture screw, or do you have to have the timing relay for 95 ron with cat and then disconnect the Lambda sensor?

As a cold Lambda will not give a reading, if you have a cat and Lambda sensor does the mixture screw reading get taken into consideration when the Lambda sensor is cold and is this the base mixture reading.

If the base mixture is too high and the Lambda tells the ECU to lean the mixture and vice versa, does this lead to premature degradation of Lambda sensor and / or overworking of the ECU leading to a less responsive engine and that horrible flat spot we all hate, compared to a base mixture that is correct?
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x2 33 16v
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[BigAl]

I think i lost everyone and didnt make a point
I was thinking that the flat spot could be caused by the lambda correction, i know the injectors are cut at 1200 rpm and causes the jerk we all know about but when i run with no lambda it is much smoother, also the jerk wasnt there when i had my other ecu chip, just curious as to whats causing it?
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[Admin]

Hi

Thought the fueling cut at far higher revs than 1200 when the throttle was closed.

I would guess that it you are seriously over fueling that there is a fair amount still in the inlets, smoothing out the transition.

All the best

Keith
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[BigAl]

I think so too, i have'nt had a chance to test emissions before the cat on idle with no lambda, cant find a probe small enough, lol
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203