Idle speed, XJ40, Daimler 3.6, '89

XJ40
1

Daimler, '89, 3.6, idles at 800 rpm after start from cold, when air temperature is 20 degrees plus, 500rpm when temperature is around 10 degrees, and not at all when temperature is below 5 degrees. It has to be held on throttle at 800 until engine heats.

Any thoughts?

Peter Parsons, Cornwall, UK.

2

Have you tested the CTS (coolant temperature sensor) for correct operation?

3

This is for the 4.0 engine, I assume it would be the same for the 3.6:

Screenshot_20210402-222639
Screenshot_20210402-2226391440×2560 309 KB

4

I would also check the Coolant Temp Sensor for proper resistance.

The idle air control valve could also be an issue for all things regarding idling.