PO 171 & 174 Codes (Lean Banks 1 & 2)

[bmruff]

Hello,

I'm in need of some help. My 2006 Land Rover LR3 (60k miles) has the check engine light on with PO 171 & 174 codes. I've replaced both catalytic converters, tried two different new mass airflow sensors (MAF), replaced the air filter, coolant temperature sensor, did a fuel injector treatment, and have a new battery.

I thought the MAF would fix things, but the codes keep popping up (after I've cleared them). This is just driving me nuts. Does anyone have some ideas or run into this before?

Thanks,
Brian

 

[waspjr123]

You more than likely have a intake leak use a propane torch that is unlit and go around your intake and specifically injector cups with the engine cold but running it will rev up or idle differently. Whe you find the spot. Just be carefully of alternator and obviously flames

 

[waspjr123]

Or you can use intake medic and spray it around. Or use a intake tester that goes in right where the maf is and pop oil fill off and air up to 8 psi and listen for leaks and spray soapy water

 

[Disco Mike]

You have been guessing too much, spending money you didn't need to.
Your cats weren't causing this no codes showing. The MAF didn't throw a code.
You you have a real time scanner, if so read the 02 signals and get back to us.

 

[bmruff]

The new catalytic converters were related to a bad cat code a month or so ago and they definitely had to be replaced. Not related to the PO 171/174 issue.

The O2 readings are as follows (at appx 675 RPM)
O2S Bank1 - range .58 - .71 (avg around .6)
O2S Bank 2 - range .575 - .70 (avg around .6)

 

[bmruff]

Also, had a shop check for vacuum leaks a week ago and they didn't find anything.

 

[waspjr123]

I would check for leaks your self

 

[waspjr123]

I would check for leaks your self

Build yourself one of these its like 3.00 and 1/2hr everyone should have one of these.

 

[srschick]

View attachment 4913
Build yourself one of these its like 3.00 and 1/2hr everyone should have one of these.

what is that, and how does one make it?

 

[waspjr123]

Its a intake leak tester
That one is for my audi its a 2.5" PVC end cap with a hole drilled in the Center where you put a rubber valve stem in you then pull your maf sensor off and put that in place. And use a tire air chuck to put shop air in regulated to 8-10 psi but pop the oil fill cap off so you done pressurize your crank case. Then the leaks are obvious. And u can use soapy water in a spray bottle. Measure your maf housing and size it accordingly