V70 2.4t 2000 idle and voltage

[Msps]

First, i am from Denmark so perhaps some words come out wrong.

I have some problems with my volvo 2.4t from 2000.

Idle is rolling from 750 to 850.

Voltage in idle is jumping up and down even with the alternator disconnectet.

The sparkplug timing is jumping up and down from 30btdc to 0 btdc.

The problem only occures and gets worse as the engine heats up..

Perfect idle and so on when its cold.

If i disconnect positive cable from alternator its the same.
Changed the starter, did not change anything

Any ideas?

Camshaft and crank sensor is new, 02 sensors working. Maf and map sensor new.


Throttle is working as it should, pefect readings on the tester

Thanks

[jonesg]

are there any codes ?

[Msps]

Not any codes.
All data looking good except the voltage pending up and down and the same thing with ignition timing.

[jonesg]

are you reading the voltage at the battery ?
Its a mystery to me.
Maybe try a load test on the battery, it might be unstable.

[Msps]

Voltage at battery, in the tester showing the same..
New battery, all negative connections cleaned and checked...
Its almost as something is turning of and on, pulling amps..
But everything is turned of..

[jonesg]

maybe you can let it idle and listen for a solenoid clicking on and off.
listen in the back , not just near the engine.

[Msps]

Had some time to look more in to it..
Had a bad vvt valve...
No fault codes.
Put when driving and accelerating i had no movement on the cam regulation..
Changed the valve and the idle is now perfect and also the spark timing..