Kv6 2.5 1999 model Cold start problem

[paul hindmarsh]

Hi all, hope everyone has had a nice Christmas.
I've had this problem for a while now. Car won't start from cold without me putting my foot on the accelerator a little to keep the revs around 1000 rpm until the Temp needle starts to move. I can then stop the enginge and start it up again without any intervention from me right foot.
I've changed the spark plugs ,removed and cleaned the Idle Control Valve , the Throttle Body ,Purge Valve, both the Balance and Power valves (for good messure) and adjusted the Throttle cable all for naught.
I decided to bite the bullet and get it in for a T4 session.
No faults recorded from anything other than the VIS motors. All parameters as they should be. Fuel pressure at crank, 50 psi and holds ok.
The mechanic is at a loss as to why the car won't start. He is e-mailing X-Part to see if they can shed some light on my problem but in the mean time doe's anyone on here have any ideas.

Just remembered the mechanic said that with the ignition switch in position 2 ,engine not running, if he operated the accelerator pedal he could hear a noise from the auto box . I've noticed this myself but thought it was normal. He said he hadn't noticed this on other 75's before himself.
Anyone have the same.

[Greeners]

Check the coolant temperature sensor, and/or wiring..........I assume it starts ok when warm ?

[paul hindmarsh]

Originally Posted by Greeners

Check the coolant temperature sensor, and/or wiring..........I assume it starts ok when warm ?

Yeah your right it doe's start ok when warm. I mentioned the temperature sensor to the mechanic and he checked the T4 reading. It reported 28.4 c
He then used what looked like a thermometer you use to check the internal temperature of a cooking chicken and said it was pretty close at 24 + c on the outside casing of the engine.
Any other ideas

[paul hindmarsh]

Bump
Really need some help here please.

[capese21]

http://www.the75andztclub.co.uk/foru...ad.php?t=50970

worth ordering a back issue as it explains how everthing works.

E.

[Kandyman]

Originally Posted by paul hindmarsh

Bump
Really need some help here please.

Sorry not many members have popped on to help but there most probably sitting in a corner somewhere still eating mince pies and drinking sherry

I was thinking it could be a CAM sensor but this normally affect starting a warm engine, Wonder if a crank sensor causes this ?

[paul hindmarsh]

Originally Posted by Kandyman

Sorry not many members have popped on to help but there most probably sitting in a corner somewhere still eating mince pies and drinking sherry

I was thinking it could be a CAM sensor but this normally affect starting a warm engine, Wonder if a crank sensor causes this ?

Thing is the T4 session didn't show any stored faults other than the VIS motor.
I've searched the internet for hours and the only other occurance of this fault was in 2007. This guys mechanic was at a loss as to the cause and sugested they systematicly changed parts till the faulty item was found. A very expesive job and the thread ended there.

[stocktake]

I'm here as usual but have no knowlage of this happening before, I would imagine the ECU recognises the engine is cold and alters the amount of fuel and air reqd

Maybe a battery disconnect for 20 mins to reset the ECU is the first stop?

[BigRuss]

Have checked through all the Rover 75 Siemens 2000 ECM reference material I have which covers all the sensors and the consequences of them malfunctioning but have found nothing that would cause the problems you describe.

If the crank sensor fails then the engine won't start, cam sensor can prevent warm starting, if most other sensors go faulty (Temp sensor etc.) then the ECM will substitute a working value.

Replacement crank sensors should be re-sync'd with the crank using testbook, should it prove to be faulty in some way.


Russ

[stocktake]

Originally Posted by BigRuss

Have checked through all the Rover 75 Siemens 2000 ECM reference material I have which covers all the sensors and the consequences of them malfunctioning but nothing that would cause the problems you describe.

If the crank sensor fails then the engine won't start, cam sensor can prevent warm starting, if most other sensors go faulty (Temp sensor etc.) then the ECM will substitute a working value.

Replacement crank sensors should be re-sync'd with the crank using testbook, should it prove to be faulty in some way.


Russ

If it wasn't receiving the temp sensor data would it substitute a working value IE a warm engine working value this would give the symtoms described