Tickover too low

Good Morning all,

When cold there is no fast idle unless you hold the pedal. After a while it runs fine, I have had the inlet off a number of times and replaced the upper and lower inlet manifold gaskets and done a compression check. I have read the ECU needs to be reset after these types of operations? I'm off to check the two temperature sensors, but any help/advice would be gratefully received.
Many Thanks.

-Mark said:

Good Morning all,

When cold there is no fast idle unless you hold the pedal. After a while it runs fine, I have had the inlet off a number of times and replaced the upper and lower inlet manifold gaskets and done a compression check. I have read the ECU needs to be reset after these types of operations? I'm off to check the two temperature sensors, but any help/advice would be gratefully received.
Many Thanks.

Click to expand...

Hi Mark. Have you had the throttle cable disconnected when removing yours bits and pieces? Worth checking its properly adjusted when refitting.

Helps to know if it is Petrol or Diesel and the Model Year!!

Saint.V8 said:

Helps to know if it is Petrol or Diesel and the Model Year!!

Click to expand...

Im going to take a punt at a '99 4.6hse... Maybe petrol as someones already assumed throttle cable!

aerofabrique said:

Im going to take a punt at a '99 4.6hse... Maybe petrol as someones already assumed throttle cable!

Click to expand...

and if it's diesel the you need to have the FIP timing checked

If there is no fast idle on cold start up petrol or diesel ECU temp sensor is duff.

Sorry, it is a 2000 RR Vogue 4.6 (66k miles).
Didn't remove the temp sensor just unplugged it, still haven't checked the wiring, spoke to a specialist this morning who said the trims would need resetting, is he wrong?

|Idle air control valve oiled up?

JamesBB said:

|Idle air control valve oiled up?

Click to expand...

No it's clean. Had the fuel trims reset -no improvement.

Hi Mark,thanks for the pm.My first thought,(Dont see many P38's now) is that there is something near the IACV with the same plug - purge valve perhaps ? I've seen these swopped and of course the IACV is not operational like this.Cant remember if it even logs any codes when plugged in like this.If nothing else was done but gaskets changed then there is no need to do an adaptive reset,people seem to think this is a cure all,but with Thor engines it often makes matters worse.If there was a vacuum leak on the inlet the Maf would instantly see an increased flow after the repair and the fueling would very quickly adapt to it.BUT,if the Maf is on its way out and the trims had long term got used to it,then it could create a new situation where the low maf reading couldnt be relied upon to give a big enough fuel map.
Have a look at those plugs,then we are down to live data etc,to see if we can pick up whats wrong.

-Mark said:

No it's clean. Had the fuel trims reset -no improvement.

Click to expand...

Had the same issue with mine. Valve was clean too, could not find the fault.
Used to idle real low and stall unless rev'd for a minute or 2 after starting.

Ended up a loose wire to the MAF. Found to be a fracture in the cable tube over the back of the alternator.

JamesBB said:

Had the same issue with mine. Valve was clean too, could not find the fault.
Used to idle real low and stall unless rev'd for a minute or 2 after starting.

Ended up a loose wire to the MAF. Found to be a fracture in the cable tube over the back of the alternator.

Click to expand...

Thankyou James. Can you remember the colour of the wire ?

Pin 1: SLG (Grey and Light Green)
Pin 2: NK (Brown and Pink)
Pin 3: RB (Red and Black)
Pin 4: R (Red)
Pin 5: UG (Blue and Green)

-Mark said:

Thankyou James. Can you remember the colour of the wire ?

Pin 1: SLG (Grey and Light Green)
Pin 2: NK (Brown and Pink)
Pin 3: RB (Red and Black)
Pin 4: R (Red)
Pin 5: UG (Blue and Green)

Click to expand...

Sadly I did not fix it, the local LR dealer I got it from did it for me under warranty. I was lucky there I got a 3 month warranty and they honoured it and replaced a part of the loom that ran behind the alternator and towards the MAF.
All I can suggest is testing the continuity, but I feel a really close up manual inspection may prove more benefical.

The idle control valve needing freeing off.

-Mark said:

The idle control valve needing freeing off.

Click to expand...

Good stuff. All ok now?

Yes, checked continuity to inlet manifold ancillaries, removed idle control valve - no movement in the barrel, score marks to one side. Cleaned - as new.
Many Thanks.