Cold start sensor ?

[AMG Merc]

Following on from my recent thread re less than perfect running after a service can someone point me to the cold-sart sensor as this could be the culprit?

[yellowshed]

Rob,

Not quite sure what you think you mean with a cold start sensor - the only sensor that the ECU uses for cold start is the coolant temperature, and then uses this to drive the gauge in the car.

You really need to get someone with a laptop to look at the throttle voltage and the fuelling trims at idle - adjust as appropriate. Noble dealers with the dealer software can do this.

YellowShed

[AMG Merc]

yellowshed said:

Rob,

Not quite sure what you think you mean with a cold start sensor - the only sensor that the ECU uses for cold start is the coolant temperature, and then uses this to drive the gauge in the car.

You really need to get someone with a laptop to look at the throttle voltage and the fuelling trims at idle - adjust as appropriate. Noble dealers with the dealer software can do this.

YellowShed

Thanks Trevor. From new on starting the car always idled around 1000rpm for a minute and then moved to a rock-steady 800rpm. Then I had it services and now it starts from cold at 1000-1200-1300rpm (whatever it fancies) - and sometimes increases, which can't be right) and then moves to the 800rpm normal idle. I thought there was a sensor measuring the temperature somewhere but otherwise what do you think it might be?

BTW, the map has been perfect from new and has never been fiddled with at all.

[AMG Merc]

Looked yesterday and there are two sensors - one on the side of the throttle butterly valve body and the other sealed into the underside of the large rubber hose going to the intercooler...

Question is what are they and what do they do?

[LJM]

I could be wrong but i'm pretty sure the one in your inlet pipe is to measure boost and the one on the throttle boby is the throttle position sensor!! better check with an expert first though!!

Lloyd

[joust]

From memory it's throttle position and inlet temp.

J

[AMG Merc]

joust said:

From memory it's throttle position and inlet temp.

J

Thanks Justin, so where does the reading for cold starting come from - if hard-coded into the map then how can it read temperature?

[joust]

Err - see Trevor's reply above on how it does it.....

[AMG Merc]

joust said:

Err - see Trevor's reply above on how it does it.....

Yes, I did so where is the coolant temperature sensor?!

[joust]

In the main block IIRC. It drives, via the ECU, the temp gauge on the dash.