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Discussion Starter #1
Guys i keep getting lean codes on my car anyone else experience this ? lean 7 and 8 and 5 only comes on when i really push the car hard car is bone stock . I had sold my white one and picked up a pearl orange . Dealers just going in circles . already changed all plugs and even the coils

to me its fuel pump or maybe just a stupid code getting triggered by something?

oh also the light does go away on its own after driving it normal for a little.

thanks guys.
 

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some fault on the wastegate perhaps. although not in the mclaren, in my 1M, i got CEL on high revs and the code mentioned lean or rich condition and i had a stuck wastegate actuator
 

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Sounds like a restriction in the fuel system, possible injector or contamination. Typically 7-8 is at the end of the fuel delivery before the return. I am not sure how Mclaren has their cylinder references noted. If; RT bank 1-4 and LF bank 5-8. The fuel supply looks to enter the right bank at the rear (4), front of motor at firewall, and exits at left bank rear (8) so 7 and 8 are at the end of the supply prior to the return.

Possible causes:
..restricted/clogged injector or bad injector.
..leak in the air intake, air box or air charge system
..contaminated MAF sensor

Under the described condition under load I would look closely at the fuel delivery. I would assume the factory test equipment has a data stream monitor. I would be interested to see what the long and short fuel trims would be on the scanner. It should also have the ability to show this data while driving when it happens and capture the error data to review. Years ago with Ford we had a "black box" that could be installed for intermittent issues where the customer depressed a button during the concern and it stored a log of data before and after the trigger.

If the data capture does not help I would swap the injectors to the suspect cylinders to two others and see if the faults follow the injectors. It does not look too involved to exchange as the rail sits between the valve covers and intake riser under the air charge/intake tubes.

David
 

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Discussion Starter #4
Sounds like a restriction in the fuel system, possible injector or contamination. Typically 7-8 is at the end of the fuel delivery before the return. I am not sure how Mclaren has their cylinder references noted. If; RT bank 1-4 and LF bank 5-8. The fuel supply looks to enter the right bank at the rear (4), front of motor at firewall, and exits at left bank rear (8) so 7 and 8 are at the end of the supply prior to the return.

Possible causes:
..restricted/clogged injector or bad injector.
..leak in the air intake, air box or air charge system
..contaminated MAF sensor

Under the described condition under load I would look closely at the fuel delivery. I would assume the factory test equipment has a data stream monitor. I would be interested to see what the long and short fuel trims would be on the scanner. It should also have the ability to show this data while driving when it happens and capture the error data to review. Years ago with Ford we had a "black box" that could be installed for intermittent issues where the customer depressed a button during the concern and it stored a log of data before and after the trigger.

If the data capture does not help I would swap the injectors to the suspect cylinders to two others and see if the faults follow the injectors. It does not look too involved to exchange as the rail sits between the valve covers and intake riser under the air charge/intake tubes.

David

David thank you seems accurate but problem i find mclaren doesn't have a tool to pin point this that was my frustration . they say fixed then give it back and then again lol. i guess back to dealer change more more parts . Thanks for your input ill try use this as a tool .
 

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David thank you seems accurate but problem i find mclaren doesn't have a tool to pin point this that was my frustration . they say fixed then give it back and then again lol. i guess back to dealer change more more parts . Thanks for your input ill try use this as a tool .
That seems odd that this day in age and then management system as well as Mclaren does not have the ability to monitor this data. It is an integral engine management software profile that directly related to efficiency and emissions. Every engine management I have run across since CAN1 and some prior have that ability. Spoke to a another McLaren shop, and was told there are abilities to monitor fuel trim....There is 10x more data available today to properly diagnose. If you are throwing parts (darts) at it you can only HOPE to get lucky.

You may need to press them a little harder to get Mclaren tech line involved and or assign it to a more seasoned tech. I would have a one on one with the service or center manager. Sad, but this day in age there are more "parts replacers" than actual technicians in " stealerships " than a real technician.

David
 
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