The Project not idling when cold

[suffolkfox]

Hi all
The Project is back on the road with its virtually brand new 3.5ltr armoured car engine (spotless and shiny inside, fitted with 10.5:1 pistons, 3.9 cam and Cloyes timing gear while on the deck and new ITG air filter). All running smoothly once warm, and suffolkfoxy is busily totting up the miles as fast as she can to get out of the running-in period

BUT

The damn thing will not idle when cold. Revs rise then fall rapidly so that you have to feather the accelerator pedal to keep it alive. After a minute it settles down, although tick-over seems high (just over 1000). I am aware of the idle adjustment but thought I would ask you all in case this is a trait of a specific component dying, before wielding any tools. I have a full set of spares as the engine came with full efi & ancillaries so can do the swapping game if needed.
Thanks
Jerry

>>> Edited by suffolkfox on Tuesday 31st August 13:39

[Gerry Attrick]

Have you done the usual set up? 2mm at throttle plate; 300mV at throttle pot; 5 half turns on idle speed screw. If so, the cold start injector or air bleed may be malfunctioning. Failing that, it could be a dicky ECU. What's the idle CO?

[CHUNDER]

Gerry Attrick said:

Have you done the usual set up? 2mm at throttle plate; 300mV at throttle pot; 5 half turns on idle speed screw. If so, the cold start injector or air bleed may be malfunctioning. Failing that, it could be a dicky ECU. What's the idle CO?

I'm no expert but isn't 2mm a bit much ?

[ssc1]

yeh it's supposed to be 0.002in on the throttle plate correct me if i'm wrong

[Gerry Attrick]

Ooops, sorry - mms and thou. Can't get my head around these foreign measurements (Centrigrade, kilometers, litres, kilograms etc). Why can't we stick with Imperial measurments - furlongs per fortnight etc.

[adam quantrill]

I must mention the number one suggestions in all the checklists: CHANGE THE ENGINE TEMPERATURE SENSOR.

Costs about a tenner and it can cause all sorts of bad running problems.

Also check the contacts to same. In fact today I cut off the plug from the wiring loom on mine and soldered the wires directly onto the sensor. It now runs much better when cold and warming up and I hope to get 100 miles from a tank next week! It probably also helps that I found and stopped a petrol leak....

[suffolkfox]

Right, quick thanks to everyone. No gap at the throttle plate and the idle had been wound to the sky but it turned out this had been done by the previous owner to try and overcome a dead coolant temperature sensor. Tested with multimeter as per Haynes manual then swapped with the virtually new one from the spare efi taken off the new engine. Adjusted all elements. Result, starts from cold and settles to idle at 850.

Also fitted thermostatic fan control for twin fans and removed leaking clutch master cylinder, fitted new seals and refitted. Pretty good for the day.

Thanks again
Jerry

>> Edited by suffolkfox on Saturday 4th September 21:31

[adam quantrill]

QED. ;^)

- Adam