I've been battling with lean codes on both banks for sometime. Sometimes intermittent, sometimes they stay longer, but they now seem to be a permanent fixture.

I purchased an Autoline economy smoke machine for about $80 as an intake adaptor for around $30. Within 5 minutes I found "a" culprit, a leaking oil neck. Giveaway was that there was plenty of wiggle and give in it. Replaced this part for $20 and the fit is so much firmer!

Followed up with another smoke test and noticed another subtle leak, around the EGR valve. Light was fading, but it looked like the smoke was leaking from the bolts on the top and not the pipes attached, see picture:

Is there anything that can be done to recondition or is it a case of a new EGR? If replacing, anything else worthwhile looking at?

Cheers.

 

If it leaking around the bolt, maybe you will be lucky and can fix it with a new gasket.

Jeff

 

Yeah, new gasket set will be less than 10 or 15 bucks. Also check the torque on the bolts. Soak in penetrating fluid before trying to remove them as they get corroded in place. I also needed some heat from a torch to free one of mine.

 

When I serviced mine, I applied a THIN coat of super high temp gasket maker and snugged it up the the next day torqued to spec. I am not a fan of those metal gaskets. Same goes for the throttle body.

 

Gaskets ordered. Will report back. Be nice if it’s a cheap fix for a change.

 

I have this same issue- It is more pressing as i cannot register my car until the environmental "issues" are resolved, such as these codes. I have replaced the 4 O2 sensors at great cost and it still persists. I am hoping to get the shop to run the tests at their expense as they were hired to fix the codes. I will use this post to inform them of a possibility.
Thank you!

 

I'd aim for a smoke test. It'll cost you around $100 (or cheaper) to do this yourself. Most garages will charge $100-150hr in labor so money well spent in my opinion.

I've also replaced my MAF, PCV , o2 sensors. Injectors are new, as one was completely misfiring.

Smoke test has shown me leaks around the oil filler neck (replaced), MAF to throttle hosing, which is leaking at the throttle end (awaiting a replacement part) and the EGR.

EGR is tricky as the leak is tiny. However, it's not from one of the metal gaskets, but from the two top bolts that don't have a gasket between them. I'm doing to try some silicone sealant and see if that works, but I think it's going to be a replacement EGR to solve that. And the bolts to remove the EGR are seized tight so need to go slow and careful to replace this piece.

 

I have been chasing a very similar issue and while I don't have a fix for your EGR (I replaced mine). I have a couple of questions for all, related to this issue.

During smoke tests, which I am currently performing to diagnose Lean Bank 1 & 2 (bearing in mind the following has been replaced on my LR3 HSE with 185K on her: EGR, MFA, plugs, injectors, knock sensor wire harness (rodent damage) - I have now replaced part # PHD500025 (air duct intake hose) 4 times. 3 brand new OEM parts are leaking smoke during the test and my mechanic bought a new part, which also leaked during a smoke test.

My question is - This part should NOT be leaking smoke along the edges of the seams of the 2 boxes, correct?

Any suggestions what substance I could use to form a seal around the seams where the boxes on either side of the hose)?

Any insight would be greatly appreciated.

Thank you!

 

I might be misunderstanding which area in the intake you're referring to, but a leak *before* the MAF sensor should not affect anything or contribute to your lean codes.
If the leak is before the MAF, then it's not unmetered air - which is what you try to eliminate with a smoke test.

 

I'm replacing that same part. Red Arrow 1 (to the left) connector is very worn and doesn't have much life. Red Arrow 2, to the right, indicates where the hose connects to the throttle body (couldn't find a picture without cover) and shows a significant smoke leak.

I disconnected the air box at red arrow one, after the MAF, got a snug fit and smoke tested. Red arrow 2 is leaking and evening tightening the hose clip (broke an old one), doesn't seem to affect the leak. So I reckon this is probably more of a culprit for me than the EGR. But, will a new part give a snug fit and stop the leak or will it continue? I guess that's the question you are perhaps asking?