Will do! Thanks.

 

Anytine

 

CEL returned after 100 miles or so: P1128 Oxygen sensing adaptation, idle range, bank 1.

Only one bank though... That is different than before.

My manometer should be here shortly, so I can test the AOS.

I need to either buy or rig up a DIY smoke machine to check for leaks.

 

So what are the MAF, FRA and RKAT readings then? It's the best time to check those values because the CEL has been tripped. It's possible 1130 may also be coming so it may not be different than before.

 

Wife just got home with it, so I pulled the codes while warm.

You were spot on, today it threw the other code (P1130) again too. So it has both P1128 and P1130.

Just measured (at idle: 790 rpm):

Mass Air Flow -> 15 kg/h
FRA bank 1 -> 1.03
RKAT bank 1 -> 4.45%
FRA bank 2 -> 1.01
RKAT bank 2 -> 4.50%

The manometer arrived today, so hopefully I can get that tested soon too. Just need to find my extra oil cap.

 

Duplicate, please delete.

 

The readings are interesting that the RKAT is only ~4%, which should not trip the 1128/1130 codes. I wonder if you have an intermittent vacuum leak. It may he worthwhile to do a test drive and monitor the MAF and RKAT in real-time (perhaps with a helper).

It does seem to point to an intake leak or a MAF with intermittent signal drop off.

 

I'll see if I can get my wife to take me for a drive this weekend while I monitor.

Any tips on what to monitor and what changes would point to particular root causes?

Would I be watching short term fuel trim for both banks and MAF? I'm guessing MAF would go to 0 if/when it fails? Would short term fuel trim go up when it experiences an intermittent air leak because it is running lean?

AOS test today, smoke test once I find the bits to make a smoke tester (or order them on amazon).

 

Amazon has become one of my favorite places for many things. Even an oil fill cap. Free shipping on most of my orders, really make it easy to justify.

 

Not to muddy the water, but does your Durametric read stft values as RKAT or TRA?

 

Thanks. They're my go to as well.

I know I have a spare somewhere in the garage though. The best way to find it is to buy a new one, then I'm almost guaranteed to stumble into the one that is already in the garage. Lol

 

That's a good question that I don't have an answer to. I've been using my Foxwell scanner since it is more convenient than dragging out the computer.

The Foxwell shows it as adaptation, range 1 or 2 with FRA and RKAT in parentheses:

 

To maximize the resolution, you want to plot the reading in Durametric in real-time, choose the highest sampling rate and monitor as little number of parameters as possible. So I would just monitor rpm, MAF voltage (in voltage, which is the raw measurement, as opposed to calculated values), and FRA and RKAT on both banks.
The MAF reading should never drop to 0v (if it does, you have an MAF with intermittent failure. I saw a case like that before). The RKAT will vary in much more than the FRA but it should stay within a few +/-% (your current reading is ~+4%). To trip the 1128/1130, I think RKAT has to go to +/-27% or so but perhaps someone else can confirm.
I just want to see whether your RKAT goes beyond the +/-27% then goes back to normal during the drive.

In any case, a smoke test will be more direct to check for intake air leak. However, keep in mind you still won't be able to verify any leak in the vacuum system (evap, intake resonance flap) because there's a one-way valve that prevents the smoke from reaching those components. To test those components, the only way I know is to use a vacuum pump on the vacuum line that plugs into the intake plenum.

 

Wow, you're really a lifesaver here. You're a massive asset to this community. Thanks for all of the time and energy you're putting in to help me.

I'll use Durametric to log the drive and see if I can get any clues. Fingers crossed.

 

Yep - I have many duplicate tools and parts as a result of this...