hot start issues

[ziopinulo]

Before buying anything try just unplugging lambda sensor and see if its any different

thanks mike.
i've tryed disconnecting lamba sensor and nothing has changed! same problems and same performance. then is it the guilty?
what exactly is the function of the o2 sensor?
lambda sensor is responsible just for controlling emissions?

[UrS4boy]

what exactly is the function of the o2 sensor?

Click on the G39 label in this link I provided to you the other day and learn

http://members.shaw.ca/ajmills/UrS%20Engine%20Bay%20Device%20Map.html

[SteveH]

thanks mike.
i've tryed disconnecting lamba sensor and nothing has changed! same problems and same performance. then is it the guilty?
what exactly is the function of the o2 sensor?
lambda sensor is responsible just for controlling emissions?

There should be a difference if the lambda sensor is working, unless fuelling is being badly affected by another source. I would borrow or purchase a replacement O2 sensor and give that a try.

[ericd]

have you got any means of pulling codes for this, g62 problems usually get caught

[John.]

......this link I provided to you the other day and learn

http://members.shaw.ca/ajmills/UrS%20Engine%20Bay%20Device%20Map.html

Great info there.

[ziopinulo]

Click on the G39 label in this link I provided to you the other day and learn

http://members.shaw.ca/ajmills/UrS%20Engine%20Bay%20Device%20Map.html

thanks dave

[ziopinulo]

have you got any means of pulling codes for this, g62 problems usually get caught

yes i've vagcom but no error displayed for g62 and engine coolant temperature showing ok in meas block

before i've tryed disconnect the two white wires from lambda but i learned that signal is on single black pin. i'll make other test

[mike74]

The lambda's can still give a believable signal to the ECU even though the signal itself is incorrect. This wont throw a code unless it goes way off the chart or there's a physical break in a circuit somewhere. If the sensor's never been replaced and mileage is reasonably high then probably prudent to replace it. My one wasn't throwing any codes and had never been replaced at about 140k miles. It had a beard when I pulled it and smoothed the engine out a bit too

[newsh]

. It had a beard when I pulled it and smoothed the engine out a bit too

Pics? [emoji51]

[mike74]

no pics I'm afraid but it had a beige father xmas-esque beard dangling from it. definitely more than a 9 o'clock shadow!

[Dynasty]

Check voltage between O2 sensor signal wire and GND. Should oscillate between ca 0.2 and 0.9 Volt... (0.2 lean, 0.9 rich). Also check for resistance between the white wires (10 ohm(?)) (to verify that the heating element in the O2 sensor is ok). NB! The O2 sensor is a "downstream" sensor so even if a signal from the O2 sensor is "off the chart" we should not automatically rule the O2 sensor faulty...

[ziopinulo]

Check voltage between O2 sensor signal wire and GND. Should oscillate between ca 0.2 and 0.9 Volt... (0.2 lean, 0.9 rich). Also check for resistance between the white wires (10 ohm(?)) (to verify that the heating element in the O2 sensor is ok). NB! The O2 sensor is a "downstream" sensor so even if a signal from the O2 sensor is "off the chart" we should not automatically rule the O2 sensor faulty...

many thanks Dynasty!
i've checked both. between white wires of my probe i've ∞ ohm.
signal wire is fixed to 0.48V all the time with engine on. i've started engine from cold and waited as long to heat up, no changes!

[mike74]

sounds like its FUBAR then