my quest for low starting revs and not so rich mixture

[escu_calin]

FTO GR nonMIVEC
my car at startup and in the morning and evening , when is cold.. generally, it revs on cold startup up to 3200 RPM.

i did the following things to find a foult and fix it:
1) removed stepper motor valve,
2)cleaned inside of throttle body and also the stepper nozzle
3)cleaned and oiled(wd40) the inside of the stepper motor
4)measured both of the coils inside the stepper motor, and they are both at 45 ohm - middle point and 96 ohm full coil.
5)plugged the stepper motor while dismounted , to see it react.
it does react,when i turn key in contact(not starting the engine)
6)since the revs kept going , i removed the electronic part of the stepper and left just the nozzle in.
i started the car with the nozzle fully retracted , and did the job of the stepper(rotated the axe of the stepper nozzle) until i reached 900-100 RPM
At the end of step 6 i am more in dilema than at starting, because if the mecanic of the stepper is doing its job all is left(by my knowledge) is the ECU or the stepper coils.

The car still revs high cold and if i press the acceleration , the revs go up to 5 k and they go down very slowly(2.5s-3s), not as they should (like 0.7-1s)

For the rich mixture i bought a oxigene sensor for replacing the old one, this:

http://cgi.ebay.co.uk/BN-Universal-4-Wi ... 1c0de7423c

Can you please tell me how to proceed with the revs , and if the O2 sensor shown above fits (24 mm-External NUT; 18 mm mounting thread; and sensor tip: 18 mm depth and 12 mm diameter)!

Regards!

[CJ]

Are the revs high when the engine is hot? If so, my guess is that someone has turned up the idle speed screw to mask a dirty or faulty stepper motor, try reducing it down to 800 rpm when warm. If the engine cuts out when cold, you may need a new stepper motor (cleaning the mechanism doesn't always fix the problem.

CJ

[escu_calin]

Are the revs high when the engine is hot? If so, my guess is that someone has turned up the idle speed screw to mask a dirty or faulty stepper motor, try reducing it down to 800 rpm when warm. If the engine cuts out when cold, you may need a new stepper motor (cleaning the mechanism doesn't always fix the problem.

CJ

the engine runs smooth and silent at 700rpm while hot !
i forgot to smell the resulting gases while the engine is hot .. to see if the mixture is still high on petrol vapors.. but this i guess is another business

[escu_calin]

Are the revs high when the engine is hot? If so, my guess is that someone has turned up the idle speed screw to mask a dirty or faulty stepper motor, try reducing it down to 800 rpm when warm. If the engine cuts out when cold, you may need a new stepper motor (cleaning the mechanism doesn't always fix the problem.

CJ

As i said before the engine revs very high when cold, meaning that the stepper is opening a bit to much, and the resulting mixture is a bit high; but the rev come down slowly in about 5 minutes.

And by removing the coil part from the stepper ; i managed to bring the rev while cold down to 800 RPM(so is possible) What i need to know is why the ecu or the stepper dont do this by themselves (who controls the stepper position , and by what parameters ? do u know?)

[CJ]

the engine runs smooth and silent at 700rpm while hot !

If thats the case then I suggest you try getting a loan of a working stepper motor and swap that in to see if it makes any difference, if so, you'll need a new stepper (I'm assuming you've undertaken a diagnostic and no other sensors are being flagged as faulty).

CJ

[escu_calin]

the engine runs smooth and silent at 700rpm while hot !

If thats the case then I suggest you try getting a loan of a working stepper motor and swap that in to see if it makes any difference, if so, you'll need a new stepper (I'm assuming you've undertaken a diagnostic and no other sensors are being flagged as faulty).

CJ

no diagnostics device available; and no lights pop on my dashboard.. but often the stepper does not show on diagnostic..
All i want to avoid is buying a new one if unnecessary ! is pretie straight forward .. 2 coils and a magnetite center .. what the hec can go faulty inside ?
130 E ... is a bit salty!

[CJ]

no diagnostics device available; and no lights pop on my dashboard.. but often the stepper does not show on diagnostic..
All i want to avoid is buying a new one if unnecessary ! is pretie straight forward .. 2 coils and a magnetite center .. what the hec can go faulty inside ?
130 E ... is a bit salty!

1. First things first - complete a diagnostic check -its free and easy - search the forum for 'diagnostic'.
2. A faulty stepper motor will appear as fault code 15

Many people on this forum have had to replace the stepper, cleaning it often doesn't solve the problem.

CJ

[escu_calin]

1. First things first - complete a diagnostic check -its free and easy - search the forum for 'diagnostic'.
2. A faulty stepper motor will appear as fault code 15

Many people on this forum have had to replace the stepper, cleaning it often doesn't solve the problem.

CJ

roger that .. on it !
never minded very much on diagnostic... thought symptoms spoke by themselves

[escu_calin]

no.. no errors on diagnostic
but as i said the stepper does somehow its job but not so good and not while cold

[CJ]

stepper does somehow its job but not so good and not while cold

You know what to do - either buy a new one or live with the idling problems.

CJ