only one black spark plug

[MikeC]

Wire connected to the temperature sensor feeding the ECU? ECU may think the engine is cold give it a bit of choke.

 

[pete30nz]

I took the injector rail out yesterday, re-seated the o.ring seals rail end, and put back in, because I found a leaky injector. Will check the spark plugs in a few days.

 

[pete30nz]

Wire connected to the temperature sensor feeding the ECU? ECU may think the engine is cold give it a bit of choke.

Hi,
Is that the big temp sender for ecu, opossed to the small water temp sender.
Or the intake air temp sensor?

 

[Immortality]

Wire connected to the temperature sensor feeding the ECU? ECU may think the engine is cold give it a bit of choke.

That would effect all the spark plugs so not likely the issue.

 

[pete30nz]

That would effect all the spark plugs so not likely the issue.

Hi Immortality, 6 spark plugs are all sooty.
Maybe I didn't word it right with my first post in this thread

 

[MikeC]

I haven't got a V6 but my Holden manual shows the relevant V6 temperature sensor just under the brake master cylinder,

 

[pete30nz]

I haven't got a V6 but my Holden manual shows the relevant V6 temperature sensor just under the brake master cylinder,

I think that's called the inlet air temp - iat sensor

 

[MikeC]

Don't know. It's in the block and GMH call it a coolant temperature sensor.

 

[pete30nz]

I haven't got a V6 but my Holden manual shows the relevant V6 temperature sensor just under the brake master cylinder,

I Don't recall one under the brake master cylinder mate.
Either under the alternator for the ecu temp sensor, or the back of the drivers side intake manifold for the intake air temp iat sensor

 

[MikeC]

I haven't got a V6 to check. If the ECU senses engine temperature from the one under the alternator then that's it. If it reads cool to the ECU the engine will richen the mixture. Maybe start by checking the wire is still connected.