Poor fuel economy - 6L manual

[Ginger Beer]

It looks like your car may be running a bit rich judging by your old plugs.

Hopefully it's just carbon build up and not from oil

Those plugs look 'orrible

OP, are they the right heat range?

 

[07GTS]

just chuck some TR6 plugs in will be fine dont have to go fancy, if there was a same shade of buildup on your 02 sensors then id prob check them out make sure they are working right and not lazy

 

[losh1971]

just chuck some TR6 plugs in will be fine dont have to go fancy, if there was a same shade of buildup on your 02 sensors then id prob check them out make sure they are working right and not lazy

This ^^^^^. I fitted NGK TR6 and it's been fine.

 

[Drawnnite]

Just to add.
If you have a live reading scan tool consider taking it for a drive with it running and a passenger looking over it.
Might show the Oxy Sensors making it rich etc.

 

[exanVZ]

just chuck some TR6 plugs in will be fine dont have to go fancy, if there was a same shade of buildup on your 02 sensors then id prob check them out make sure they are working right and not lazy

replaced those ones with TR6 plugs

O2 sensors not sure how they look, or how old they are, but yea I'm thinking now it might be something like that causing these issues.

edit: I'm pretty sure there's just 2 pre-cat O2 sensors, will have to work out if they're new or not and have a look at them, if they're not that expensive might just replace em anyway.

 

[exanVZ]

Just to add.
If you have a live reading scan tool consider taking it for a drive with it running and a passenger looking over it.
Might show the Oxy Sensors making it rich etc.

unfortunately don't have a scanning tool, I do have an OBD2 bluetooth dongle but not sure it would give the necessary data.

 

[exanVZ]

Hopefully it's just carbon build up and not from oil

Those plugs look 'orrible

OP, are they the right heat range?

not sure how old those plugs were, might have been swapped when it first got tuned but I can't recall, I don't think they would have put those plugs in though. it's possibly they are the original plugs as engine only has 120k on it. will have to go through some old paperwork see if it's been replaced in the past.

 

[losh1971]

I spoke to a bloke in the trade and he shunned when I bought Delco iridium plugs. He was much happier when I decided to go with standard NGK's.

 

[07GTS]

yea the iridium's keep a hot tip for emissions but its not good for making power

 

[MuckUte]

unfortunately don't have a scanning tool, I do have an OBD2 bluetooth dongle but not sure it would give the necessary data.

When used with an app like Torque it should be able to read the data to help with a diagnosis.

I would be checking short and long term fuel trims first. These will show if the ECU thinks its running lean and adding more fuel.

It should also be able to look at O2 sensor voltage to see if the ECU is seeing the correct info from them.