Idle issues...

[helderteixeira]

Still with issues adjusting idle... think now I know where's the issue... I have adjusted the screw to idle 900 rpm. After 2 or 3 minutes drops to 700 rpm. If I reset the throttle position (ecu)goes immediately back to 900. After 5 minutes goes back to 700... sometimes stays longer but as the time goes reverts to 700. Any thoughts?

[tofts]

Are you just adjusting idle or have you tried balancing throttle bodies? Will prbably solve this. If it fails to idle properly after a balance and reset, perhaps you have wear on throttle bodies allowing more air through.

[Milky400]

As above, sounds like throttle body spindle wear.

[nawarne]

....Yep, my first shout would be TB spindle/bearing wear. I believe the idle then becomes quite erratic - as in 'hunting' continuously?

My 2nd thought would be the throttle position potentiometers? These do wear and the resistance 'track' is lost or breaks/becomes corroded. Might explain why the rpm changes after a reset on the laptop and then revving engine?

Nick

[helderteixeira]

Nick,
Erratic but not much let say when warm it fluctuates from 780 to 890 continously up and down between those values... but I don't have the experience to know if it's acceptable this variation? I'm not sure what else can I do here "alone" in Dublin

[Sagi Badger]

Dallas chip

If you had an air leak it would not drop off as you describe, it would be erratic or fast. The closed loop would "up fuel" if you had oxygen passing the lambdas meaning a fast idle. I have seen throttles closed and an engine running on air leaks.

The Dallas chips have a battery for memory storage, most of the original devices are past their best now. I had one fail, ummhh very odd behaviour and it wouldn't idle. Stripped another ECU, swapped out and problem sorted, even ran it on donor adaptives first of all. If you buy one on line check the part number carefully, there are different speeds and capacities. Easy to fit, ECU in foot well, unplug, take out and remove four screws, spot of static protection and pop one out and one in. The holder shows how they are orientated but a pic before you remove is safest.


J

Hope this sorts it

[helderteixeira]

Hi Sagi,

Thank you, to clear my thoughts... I was exactly pointing to the Dallas Nvram.
I have clean a big number of earth connectors... just peace of mind.
I was about to order the dallas ram, remember a post a while back with someone with issues with lambda and adaptatives, turns out Dallas... I have order the DS1230AB-70IND+ see if works...

[helderteixeira]

still all the same after changing the Dallas.... now failed doing the MOT lambda measured 1.17 the limit on the MOT (NCT) in Ireland is 1.03.... bought 2 new Catalytic converters and got ok on the co2 emissions but still failing in Lambda.. any help ?

Edited by helderteixeira on Wednesday 30th November 12:47