Gents - hate reposting for this but I’m struggling to figure out the cause of my returning lean codes on both banks. At this point, inspection sticker is expired and I’m in denial that it may soon be time to take her off the road and part her out or Just drive her off a ravine. For what is worth, she has 235k on her and 200k of them are from me. Here is the list of things I’ve done to try to fix.

- pray
- smoke tested with a diy machine - no visible smoke anywhere
- oil filler neck replaced
- new plugs
- new coils
- new PCV valve
- cleaned Maf
- then replaced maf
- air filter
- OTC fuel injector service
- I also replaced those oil prices
- VVT seal

i dont have a big budget for this - but the “throwing parts at it “ strategy is a failing one.

Here is some data i captured. Anyone have any suggestions ?

https://imgur.com/gallery/wrbgAud

 

How old are the O2 sensors and have you checked the connections for corrosion?

Also sounds weird but check and clean your grounds. Don't forget the one in the passenger wheel well behind the liner

 

Ah! Forgot something. O2 sensors were replaced but he had some issue. Here is what he noted on the bill of sale

https://imgur.com/gallery/KciQ4ky


since you’re mentioning grounds, I had replaced the battery terminal end on the negative side. I used a solder style end vs a clamp down style.

Could that possibly be it ?

 

And also - what connections ? The plugs on the O2 sensors ?

 

What brand MAF? Denso are good. I have had Delphi that are bad out of the box.

 

Is the broken clamp on the down pipe causing an exhaust leak before the rear o2? Also I see one front and rear did they do both sides.

Grounds I am referring to are the ground points to chassis and body

 

Will check Abran. Certain it wasn’t a LR genuine part or a denso. Dura something ...

is there anything in the data that makes you think it’s the MAF sensor ? You’ve been right about every diagnosis you’ve made for me.

 

Excellent advise. Having replaced many MAF sensors in my career, I have only found two brands of sensors that work well in these cars: Denso and Genuine (also a Denso). Anything else will have you chasing your tale. I can't say for sure that is the magic "fix", but its a really good place to start.

 

Well - I went poking around for the O2 sensors to see what that last Indy was speaking about. Here’s what I found.

https://imgur.com/gallery/J1yK9oT

my question is - could this be the cause of the lean codes ? Is the exhaust simply not on property as a result of this bolt that is not wanting to move ? Sucking in air ?

 

Do you have lean codes for both banks or just one bank? An exhaust leak on one bank, will not effect the fuel trims on the other bank. So if both banks are lean, then you either have exhaust leaks on both sides, or you have a global issue (effects both banks, i.e. MAF sensor, intake leak, low fuel pressure, etc...).