Engine: 70: Cold start hunting. 2.4T petrol auto.

[GaryS40]

Hoping someone can assist with this one...

A few months ago, I was having issues with the V70, as it would intermittently cut out, when stopping at a junction or traffic lights, but I could start it up again, straight away.
I replaced the MAF sensor and it seems to have cured this problem. Non Bosch unit.
Now, only on a cold start, the car seems to be hunting a bit, for a few minutes, while heating up.
If I drive away, it doesn't stutter at all, just when idling.

Can anyone advise what could be causing this?

Gary

[Clan]

Originally Posted by GaryS40

Hoping someone can assist with this one...

A few months ago, I was having issues with the V70, as it would intermittently cut out, when stopping at a junction or traffic lights, but I could start it up again, straight away.
I replaced the MAF sensor and it seems to have cured this problem. Non Bosch unit.
Now, only on a cold start, the car seems to be hunting a bit, for a few minutes, while heating up.
If I drive away, it doesn't stutter at all, just when idling.

Can anyone advise what could be causing this?

Gary

Try cleaning any carbon deposits which may have built up around the throttle flap , it would be reducing the air flow at idle .

[GaryS40]

Originally Posted by Clan

Try cleaning any carbon deposits which may have built up around the throttle flap , it would be reducing the air flow at idle .

Thanks for the info, Clan, but would the idle not still be affected, when the engine was warm too?

Is there a cold start system on these engines, that may have a faulty/dirty component?

Gary

[Clan]

Originally Posted by GaryS40

Thanks for the info, Clan, but would the idle not still be affected, when the engine was warm too?

Is there a cold start system on these engines, that may have a faulty/dirty component?

Gary

No, the cold start programme is all incorporated into the Engine Control Module .
have you checked for any stored fault codes ? possibly an air leak through a cracked hose ? That would bring up a message after a while though .

[GaryS40]

Originally Posted by Clan

No, the cold start programme is all incorporated into the Engine Control Module .
have you checked for any stored fault codes ? possibly an air leak through a cracked hose ? That would bring up a message after a while though .

There are no fault codes on the code reader (other than the external temp sensor is faulty, even though recently replaced), or warning messages on the dash.

Might need to get a smoke generator and check for any air leaks.

Gary

[Clan]

Originally Posted by GaryS40

There are no fault codes on the code reader (other than the external temp sensor is faulty, even though recently replaced), or warning messages on the dash.

Might need to get a smoke generator and check for any air leaks.

Gary

The engine ECU uses the external temperature sensor in it's calculations , it might think it is a hot day when starting .... although the main air inlet temperature sensor is in the air mass meter.

[barrybritcher]

cracked coil packs?

[Familyman 90]

Check the MAF, a favourite cause of hunting on older petrol engines. Might also be worth checking the resistance you're seeing on any coolant and intake temperature sensors while theyre stone cold, seeing if its within range.

[GaryS40]

Originally Posted by barrybritcher

cracked coil packs?

They are all only a year old, Barry.

Hope they're not cracked already!🤯

Gary

[GaryS40]

Originally Posted by Familyman 90

Check the MAF, a favourite cause of hunting on older petrol engines. Might also be worth checking the resistance you're seeing on any coolant and intake temperature sensors while theyre stone cold, seeing if its within range.

MAF was replaced about 8 weeks ago, as it was cutting out at junctions etc, when up to temperature. The new MAF sorted that out.

Gary