just inspected/passed, now throwing codes at me
 

I've started driving my '01 a bit more this past week, starting off by getting the annual safety/emissions inspection. I scanned it for codes prior to the inspection, and only had one for the passenger airbag (wouldn't clear, after inspected), and none for the remainder of the systems.
Attachment 81200

I made three more 20+ mile trips later, and on the second one I got the Service Engine Soon light, about two miles from home. I checked it with the Foxwell NT510E first, then with my Innova 3100i scan tools; both showed P0171 & P0174 (lean misfires banks 1 & 2). I hadn't noticed any stumble or such while driving (I'm very sensitive to those, after 50+ years tuning by vacuum gauge & feel-of-the pants driving perceptions). I dismissed them/cleared the codes as glitches, since there had been no problems a day earlier, or at the inspection three days prior.

On my last trip, I was watching out for anything amiss, and saw the SES light come on at the same spot as I neared home (a hard right turn after hard braking, due to tail-gating traffic). Still no driveability problems. This time there was an added P0313 code (misfire detected with low fuel), and I detected a whiff of oil smell under-hood (never before; no obvious valve cover leaks). I looked at the freeze frame on the Innova, which showed the rpm as 2811, consistent with the hard turn SES activation situation. I was going to take a photo of the freeze frame, but didn't have my phone handy, and just cleared the codes and moved on to diagnose two DTC's on my wife's HHR Panel (TPMS warning...three sensors gone dark, and passenger seat airbag warning...from a spilled vase of flowers saturating it), before she went out of town overnite.

I plan to get a fog/smoke machine, replacement vacuum gauge & tester kit (I lent mine out awhile back), Mass Air Flow sensor cleaner, and utilize my inspection camera to try and detect any vacuum leaks, next week. I'll also inspect the CCV system, which may be original to the car, and 20 years-old (a previous once-over detected no mayo under the cap, nor loss of oil, nor cracked hoses).

Since I'm new to the BMW, with all the "modern" tech to decipher, should I look at any other spot while I'm searching for anything amiss?

Ahh yes...the ever popular P0171, P0174 and P0313 codes. Welcome to the M54 world

The majority of the time these are related to vacuum leaks. If you smell oil then it could be the valve cover gasket. Usually you can notice it on the front of the engine on the passenger side.

The rubber intake boot is a very popular source of vacuum leaks. The accordion part of the boot is prone to cracking and can cause all kinds of problems.

However the best way to know for sure is smoke test it like you mentioned.

Anything gasket/rubber hose on these cars basically need replacing.

I built my own smoke tester when I had the same issues. Mine had a leak at the ICV hose and the oring at the DISA valve. Fairly simple fixes and got a smoke tester for about $35

researching smoke machines/foggers/beekeepers' smokers, etc.
 

I'm leaning toward just buying a "fog machine" (makes a fog-like mist as seen on stage plays, movies, musical acts), with no need to hook up a compressor, nor use any fire source...it's self-contained, has remote control, and uses 110vac. As accident-prone as I have been, I really don't need a live fire source near my X5 (or me). Besides, for $50 (Amazon), I can actually have it delivered, ready to run, without sourcing all the pieces I'd need to rig one up (taping a vacuum cleaner hose to the output would be the only thing needed).

There were some devices on YouTube that were pretty good, but just buying the parts needed would have cost me about the same as the fogger (I had none of the parts on hand). I saw a "briansmobile1" video where he used a fog machine, and it made sense to me as an alternative. Why not?

Today, before my machine is ordered, I'm going to heat the engine up to operating temp, to see if there's an indication of too much suction at the oil filler cap (CCV test), evidence of "mayo" there, as well, and spray brake cleaner on the intake rubber to see if the engine speed changes. If I can spot a vacuum leak this way, I can use the fog machine money towards repair boots for the intake.

a new code, P0365; the original three codes went away
 

It's been over a month since I reported three codes that popped-up just a few days after the X5 passed inspection. I detailed my plan for repairing the DISA and smoke testing with my home-built tester: here https://xoutpost.com/bmw-sav-forums/...s-codes-4.html and here https://xoutpost.com/bmw-sav-forums/...oday-1443.html It's been almost 10 days since the repaired/upgraded DISA was re-installed, and the first few times I actually started the engine (ran it for 30 minutes two days ago, drove it for 12 miles in traffic yesterday, and again today for 15 miles). Never had a chance to smoke test it, with it outside in strong winds, and my smoke machine's output being somewhat feeble.

The 30 minute run-time didn't trigger any codes, nor did the low-speed in-traffic drive yesterday, but today's drive did generate a new code, but not the other three: P0365 - Camshaft Position Sensor 'B' Circuit Bank 1. The only thing I did different, was accelerating rapidly onto a freeway, while dodging a truck trying to enter from a side street. I floored it (or moreso than usual, since I've been babying it), and could really feel more power than before (the pre-repair DISA was sticking). But, the SES light popped-up; the engine load, speed, and low-ish rpms seem to indicate the SES was triggered as I decelerated, as I suspected had occurred on the other three codes. I guess I'll keep driving it until it fixates on a particular code, so I can repair it ????

Here's what my Foxwell showed
Attachment 81390

longest drive yet in the X5 triggered more codes
 

We drove to the in-laws ranch, 50 miles each way, for family Christmas (hers...mine are all gone). I'd never driven the X5 on hills, switchbacks, gravel, etc., nor at 75+ mph for long stints (previously only getting on the freeway on short trips).

Overall, it was surprisingly agile and definitely handled railroad crossings, potholes, and the gravel-covered approach to the ranch (a long downhill curve on a tall hill; coming back up it is easier with the X5's AWD) better than any of my 2WD trucks or FWD compact daily drivers do. It does downshift faster and more often than my V-8 trucks do on high speed hills (of course there's less torque and horsepower available than the tuned 5.7L and 6.0L trucks possess), but it was finely controlled, and the speed increase was just enough. I still haven't mastered the Cruise Control though; one click up gets me much more increase in speed than the CC on the GM trucks.

Also, on this trip, I intentionally watched for the kick-in of the opened DISA valve at about 4000 rpm; it really makes a difference (before the DISA upgrade/repair, there was no difference on two "floored" attempts).

Now for the Service Engine Soon codes (there were also about 8 more hidden codes concerning steering angle and other momentary, "implausible" codes, that go away by themselves). Again, there's the P0365 (exhaust camshaft sensor), but this time accompanied by a P0505 (idle air control valve not working correctly). The P0365 triggered at a completely different situation than it had previously:
Attachment 81492
so I assume that I need a new camshaft sensor, since it's showing signs of variance in different situations. The P0505 is new, though. I saved the P0505 freeze frame, but when I brought the Foxwell scan tool into the house to photograph it, it wouldn't display it.

I guess I should've removed & rattled it when I redid the DISA; is it necessary to remove the DISA to test the idle control valve?

It may just be pointing to an intake vacuum leak; I still haven't smoke or visually tested there, nor have cleaned the MAF, either. Though the P0171 and P0174 codes haven't reappeared, I suspect they're not gone for long.

POINT OF ORDER
P0171 and P0174 only mean that the air fuel ratio is lean, they do not mean that there is a misfire. There could be a misfire, but the P0171/P0174 are not how you would know.

runs smooth as silk; no "felt" misfires
 

I've yet to feel any driveability problems, but then I'm more used lately to GM Ecotec 4's, modified GM V-8's, and full-race thumping-cammed BB Chevy motors. I'd never driven a BMW before I got mine, and always heard that the straight sixes were smooth, which mine is.

As long as the codes come & go, without misfires, stalling, or limp home mode coming, I can live with a light show on my dash, as many have had before me. Right now, the passenger airbag an the SES light are on, and I always drive with Torque Pro running (and the Foxwell in the back), so I can deal with sketchy codes on the road.

Looks like you need a cam sensor and to clean the IAC valve. They rarely fail outright, but do commonly get gummed up which cleans up just fine with some carb cleaner or like solvent.

YOU said that you had P0171/P0174, "lean misfires, bank 1 and 2." This is a false statement. You have a lean fuel mixture, but you do not have misfires, at least not from these codes. All you have is Lean, banks 1 & 2.