Misfiring Range Rover Sport 4.2 SC

ptrustfull · Jan 13, 2021

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

tomcat59alan · Jan 13, 2021

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

kermit_rr · Jan 13, 2021

Misfire codes for all cylinders or just some?

kermit_rr · Jan 13, 2021

125psi sounds like to me?

ptrustfull · Jan 14, 2021

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.

Mark Piercy · Jan 14, 2021

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

kermit_rr · Jan 14, 2021

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

AdamD1 · Jan 14, 2021

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!

Misfiring Range Rover Sport 4.2 SC

ptrustfull

Member

tomcat59alan

Well-Known Member

kermit_rr

Very

kermit_rr

Very

ptrustfull

Member

Mark Piercy

Well fumbled member....

kermit_rr

Very

AdamD1

Well-Known Member

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