Ve ly7 misfire on 6th cylinder

[Dozer31]

Hi All
Seeking some more advice.
Timing chains just completed again and after start up I have a misfire in bank 2 cylinder 6.
Car starts and runs fine but you can easily tell by engine note and acceleration.
First fault that come up was cam sensor B bank 2 exhast (p0391) which sensor was changed and not seeming to throw this code anymore.
But still has misfire on cylinder 6. (Code p0306) I have swapped coils and it's not that. Also checked spark plugs which are still near new.

Before anyone asks when charging timing chain again All timing makes are spot on with no teeth being out of place.
One other note is when chain works have been done lower manifold was still left in place with fuel line still connected just moved side to side to access rocket covers.

Fault code cleared but still returns with motor still running a little rough.

Anything else I should be checking before it goes to my mechanic?

 

[krusing]

Check the -
injector connector,
The multi pin injector connector under the back of the manifold,
The coil plug,
ECU plug

 

[krusing]

On a site note,
I removed the Manifold & the lower manifold when I did mine (twice),
Was much easier to work on the motor.

 

[Dozer31]

Check the -
injector connector,
The multi pin injector connector under the back of the manifold,
The coil plug,
ECU plug

Yeah I have already removed th plenum to access this rectangular plug removed red tag to open plug and check connection with not making any difference.

 

[convas]

Have you done a compression test on it ?

 

[Dozer31]

Have you done a compression test on it ?

Yep done compression done including oil pressure test with both being ok.

At a guess I'm thinking Injector or wiring issue.

 

[Dozer31]

Yep done compression done including oil pressure test with both being ok.

At a guess I'm thinking Injector or wiring issue.

I'm also not sure if and how to test the power at the 6 cylinder plug that feed this coil pack.
Plug looks ok but it would be good to see if this can be tested with a multi metre to confirm power to coil is all good.

 

[Dozer31]

Hi All
Problems solved.
Even though I thought I previously checked this I decided to remove the cylinder 6, spark plug and to my surprise a lovely crack running down the top section of the plug.
Replaced with new and now we are back up and running.

 

[uglyoldfatbastard]

Probably a hairline fracture when you first looked and it got worse with being screwed in and out.
Had a few over the years where I have had to use a magnifying glass to see the crack it was so fine.

 

[krusing]

Hi All
Problems solved.
Even though I thought I previously checked this I decided to remove the cylinder 6, spark plug and to my surprise a lovely crack running down the top section of the plug.
Replaced with new and now we are back up and running.

Well Done,
Excellent find, of all things to be the fault,
Thats very interesting that it had caused the misfire.

I must ask, what made you look at the spark plug to locate the crack.