P2187 and P2189 - Lean on both banks

[zcacogp]

Hi, 

Another weird code post. My 2.7 987.1 Cayman has started throwing these codes. It started with P2189 (Bank 1) which popped up, I cleared it and it popped up again a couple of weeks later. I cleared it a second time and it's come back, but this time invited its friend P2187 along for the ride too. It seems that the common explanation for these is a loose oil cap, but mine is tight. 

Before I take the engine cover off and dive on in, can anyone suggest where I should start looking? I understand that these aren't common codes on 987's (a search for them shows that they are dead common on Cayenne's though), so if anyone has any first-hand experience then I'd be very grateful. 

(Logical thinking: running lean could be either an air leak into the inlet manifold after the AFM, or possibly an air leak around the lamba sensor. I have had the inlet manifolds off recently as I had to change the fuel rail on one side, which ended up meaning that both were changed and you need to get the inlet manifolds off to swap the fuel rails. This is therefore a good place to start looking, but if there is a code for both sides then I wonder if there is a single point of failure which would account for the two of them.) 

 

Thanks. 

[½cwt]

I think you already know where to start looking.  As you not lean is too much air, or not enough fuel, and that is came up one side only first suggests MAF is OK.  Pure guess, but how about starting immedialty downstream from the throttle body as the inlet system splits into two.

[Ninesomething]

I had loose clips on the throttle body connectors on my 2.7. Never threw a cel but drove better after I tightened them.

[iborguk]

https://www.planet-9.com/threads/p2187-p2189-error-codes-posible-causes.44958/

[sa utah]

On 2/19/2023 at 7:16 PM, zcacogp said:

Hi, 

Another weird code post. My 2.7 987.1 Cayman has started throwing these codes. It started with P2189 (Bank 1) which popped up, I cleared it and it popped up again a couple of weeks later. I cleared it a second time and it's come back, but this time invited its friend P2187 along for the ride too. It seems that the common explanation for these is a loose oil cap, but mine is tight. 

Before I take the engine cover off and dive on in, can anyone suggest where I should start looking? I understand that these aren't common codes on 987's (a search for them shows that they are dead common on Cayenne's though), so if anyone has any first-hand experience then I'd be very grateful. 

(Logical thinking: running lean could be either an air leak into the inlet manifold after the AFM, or possibly an air leak around the lamba sensor. I have had the inlet manifolds off recently as I had to change the fuel rail on one side, which ended up meaning that both were changed and you need to get the inlet manifolds off to swap the fuel rails. This is therefore a good place to start looking, but if there is a code for both sides then I wonder if there is a single point of failure which would account for the two of them.) 

 

Thanks. 

Check the seal on the cap.  Mine was pretty much useless and since replacing it the idle is rock solid.    See one of my previous posts where I discuss.

[zcacogp]

Guys, 

Thanks for the replies. They are all very much appreciated. 

I took it all apart today and it turned out that the AOS wasn't fully sat down in it's hole. Nice simple solution, but annoying as I did the AOS swap job myself a few months back and hence it's entirely my fault. And I'm cross with myself that I didn't do it right. 

I also discovered that the pipe that runs from the side of the AOS to the nearside bank (LHS bank) had cracked apart entirely, so I re-joined it with some oil-resistant hose and will make a better job next time I have it apart. 

A test drive didn't throw up any codes but they sometimes took a while to appear before, so it's not conclusive. However the idle is MUCH more stable and it's smoother to drive, suggesting that I may have solved the problem. 

Thanks again for the assistance. I do find myself thinking that the AOS's on these cars cause quite a lot of grief and whether life would just be easier to disconnect them, plug off the hoses running to the inlet manifold and run the crank breathers to catch cans. Would it cause any harm? Would anyone notice? I could be quite tempted.