P

ptrustfull

Member

• Jan 13, 2021

• #1

I need help with this. The car a 2006, Range Rover Sport 4.2 SC, is misfiring from start up on. Recently i replaced the head gaskets because the car overheated. Prior to this the car was allready misfiring.
I replaced coils, sparkplugs, injectors
Tried another airflow sensor
Did a compression test, 125psi (about 8.8kg/cm2) on all cylinders
Removed the exhaust to bypass the catalytic convertors
Replaced the in tank filter
The codes are all only misfire codes.
What i noticed is that the sparkplugs on bank 1 are black. Bank 2 is a lighter black.
Any help will be appreciated

 

T

tomcat59alan

Well-Known Member

• Jan 13, 2021

• #2

Air leak on inlet side of bank two? Faulty temp sensor causing rich mixture?have you changed the air filter?

 

kermit_rr

Very

Full Member

• Jan 13, 2021

• #3

Misfire codes for all cylinders or just some?

 

kermit_rr

Very

Full Member

• Jan 13, 2021

• #4

125psi sounds like to me?

 

P

ptrustfull

Member

• Jan 14, 2021

• #5

I checked for air leaks by spraying quick start on the intake manifold and other ereas. Also closed the intake to see if i can hear, see or feel suction some place else. No leakes found. A new air filter is fitted. About all cilinders show misfires. Today i removed the airflow sensor and noticed that when the car goes into limp mode i feel no more misfires. This would mean that i do not have a problem with, coil, sparkplug, injector or catalytic convertor. Could the air flow sensor be my problem? I mentioned that i switch it. Talked to the owner and he has the exact same problem.
I will also check the coolant temperature sensors on the scanner.
Please keep feeding me things to look for.

 

Last edited: Jan 14, 2021

Mark Piercy

Well fumbled member....

Full Member

• Jan 14, 2021

• #6

Does the maf sensor réspond on the diags live data?
Engine coolant sensor reading at warm and start up?
Yeah, just read that....

 

Last edited: Jan 14, 2021

kermit_rr

Very

Full Member

• Jan 14, 2021

• #7

If unplugging the maf make a difference. If be paying more attention to that

 

AdamD1

Well-Known Member

• Jan 14, 2021

• #8

I’m currently pondering an L322 and doing as much research as I can. I have come across people saying the the catalytic converter has caused one bank to record misfires. Would removing the exhaust still leave the sensors reading incorrectly and still produce a misfire?

Have also read about a small head gasket leak causing misfire when cold but clearing when hot.

Absolutely no personal experience of the matter but have read lots trying to work out how much of an idiot I am for considering one!