Uh-oh..wifey calls...rough running and CEL...

[billb]

rough running while at a stoplight, then momentary CEL at around 35mph a little bit later... I just did an "italian tuneup" last night for about 30 minutes, then went and filled up with 91 Exxon. Drove spiritedly home from that.

Wonder what I cooked up/burned out? Recently replaced valve cover gaskets, and there was no oil leakage into spark plug wells. May have fouled the O2 sensor...last replaced in 2001, at 79k miles...seems too soon for that though.

This is the worst possible timing for problems with her car. Like there's ever a good time. I'll see what the stomp test gives me.

:(

[Mr Project]

Coil(s)?

[billb]

Coil(s)?

Let's hope it's something simple.

[Jon K]

Let's hope it's something simple.
Coils are simple, but not cheap.

[Jr ///M5]

Bill, I believe the coils for the 318is and the 525's are the same. If you do suspect the coils, they are simple enough to rob for a test before you plop down the cash...only trouble is, there's only 4 of 'em...=)

Jr

[billb]

Coils are simple, but not cheap.
Checking out the cheap/simple stuff first. Oddly enough, when it's running rough, disconnecting the MAF connector causes it to run smoothly again. Might I be on to something there?

[ryan roopnarine]

ummmmm.......
1222 is o2 sensor but that doesn't mean anything. any massive vacuum leak or vacuum hose kink will throw that code (ask me how i know...) if you disconnect the maf while it is running, it should run like crap.

[billb]

still throwing 1222 code, but I did not find a leak anywhere. I checked every hose in the idle circuit, FPR, crankcase ventilation, etc. All good, no leaks anywhere that I can find. At first, it was just sporadically hesitating, then idling up high to recover, then repeating. It steadily got worse this evening as I was testing it out. Eventually, it did that enough that the CEL came on steady and it went into default mode, taking everything out of the loop, and runs smooth...but with lit CEL.

In efforts to level the playing field, I reinstalled the factory chip (removed the EAT). No change.

Suspiciously enough, I just filled up last night...wonder if bad gas/water in gas could cause all this mess?

New O2 sensor is $69.00...and it has been 45k miles since last one...that's way too short a life.

Suggestions, comments, snide remarks?

[billb]

I just can't see a large-scale vacuum leak on this thing (or even small scale!) It seems to do it once the engine's up to temperature, so it's when it goes closed-loop. It almost behaves like a shot O2 sensor, but I'm getting 1222. Of course, the last time this happened, I got 1221, not 1222.

Any thoughts of problem-prone areas? Gotta get this thing back up and running for the missus.

Thanks.

[GS535i]

... back to your earlier post re. the MAF: Do you have access to a spare one to swap out for a trial?? False air mass readings to the motronic will do many things - like richen the mixture which will cause a "red-herring" error code on the O2 sensor.
Anyway, it is possibly one of the MAF failure modes.

[billb]

... back to your earlier post re. the MAF: Do you have access to a spare one to swap out for a trial?? False air mass readings to the motronic will do many things - like richen the mixture which will cause a "red-herring" error code on the O2 sensor.
Anyway, it is possibly one of the MAF failure modes.

I've emailed our good friend Mr. Bill R...hoping he'll have the magic "AHA" fix...

Thanks!

[ryan roopnarine]

have you tried sniffing the exhaust with it running to see if any gas is gettting shot out unburned?

[billb]

have you tried sniffing the exhaust with it running to see if any gas is gettting shot out unburned?

I'll pull a plug or two tonight and take a look. Will also check voltage on the O2 sensor to see if it's sensing lean or rich. Of course, with the CEL on full, I'm guessing it's going to go full rich for safety.

Thanks for continuing the discussion!

[ryan roopnarine]

perhaps this will be helpful if you haven't seen it already

http://bmwe32.student.utwente.nl/sean750/MAF_v12/MAFtroubleshooting.htm

[ryan roopnarine]

if the cel is on constantly, but you have a normalized idle, it could be that the computer just adjusted to the problem and will try to substitute an idle speed conducive to it running somewhat properly. i'd unplug the battery and see what it does sans memory and see what problem is being covered up.

ps. i only say this because i know it from experience. if the ICV hose is kinked, the car will adapt a high idle (but steady and seemingly normal) of about 800-900-1000 rpm after about 30 mins or so of runtime. it could have adapted to whatever problem you have.

[billb]

ECT sensor checks okay. There was oil in the sensor cavity, maybe shorting out the connector. Removed, replaced with known clean good one from my E30 (same part number), and cleaned connector. No better.
Replaced FPR vacuum hose-old one looked okay, but as a matter of course...
All, and I repeat, all vacuum hoses look good, including fittings.
Valve cover gasket was recently replaced 500 miles ago, and is still sealing well.
Oil cap secure, fuel cap secure.
Charcoal canister lines look good.
Replaced o-ring on crankcase ventilation fitting at valve cover, good snug fit now.

Disconnected battery, clearing codes (1444), then repeated the earlier starting exercise. It starts smartly, runs for a few minutes, then the idle gradually becomes more unstable, until, after about 15-30 seconds, it oscillates wildly, from low 100's up to 1500 or so, about 2-3 times, then dies, running rich when it dies.

This one's got me stumped. Oh, and it hasn't thrown a code again yet...

[ryan roopnarine]

check engine service will not store codes in my car unless it is driven or runs for a very long time. you saying that it stalls out before a minute or so? i'd nurse it to high idle and try to drive it around your neighborhood and see what number it comes back with. fwiw, my friend's acura 3.2 had a bad oxygen sensor (s in his case) and it would cause his idle to do what you describe of it in your latest post (although it wouldn't stall). don't know if the same could be applicable here, i have a hard time believing that the car wouldn't have a drivable idle with a dying oxygen sensor (albeit with a drop in mpg).

[billb]

did some more snooping. Checked all coils...good. Checked all coil connectors to plugs...1.8kOhms...+/-0.1kOhm...good. Checked plugs, all fouled and black, suggesting all six cylinders are rich, kind of ruling out a stuck injector. Checked all relays in E-box...good when applying 12V, they make the appropriate circuit (tested with 9V battery). Checked old O2 sensor...hooked 9V battery up to heater circuit, then held sensor over propane torch. It is going back and forth around 0.7V rapidly according to how I hold it in the flame...good. So, the O2 sensor may be good. I managed to get it out without dropping the exhaust, so I may put it back in instead of using up my new one when I get the intake gaskets installed and idle hose connector installed. Checked every hose, including those at the gas tank expansion tank...all good. Last steps are MAF and ECU...yuck...

Will keep you all posted...I'm sure you're on the edge of your seat.

[Geoff Hoad]

That's ok, Jr's got another four in his is! :)

[billb]

It'll actually be cheaper for me to install a new FPR than to buy fuel pressure gauge...hmmmm...lots of history on stuck FPR causing rich conditions. Let's try that route, since all the sensors check out A-OK...

[ryan roopnarine]

it costs about 10-14 to make a fuel pressure gauge. does pulling off the fpr hose still fix it at this point?

[billb]

it costs about 10-14 to make a fuel pressure gauge. does pulling off the fpr hose still fix it at this point?

Let's put it this way, I'd rather not fark around making a gauge, when the car has 120k on the original FPR...eliminate the obvious then focus on the obscure. Now if I was thinking about buying a MAF just for sh!ts and giggles, that'd be different. The only thing that "seemed" to make it run better was disconnecting the MAF connector.

[ryan roopnarine]

Let's put it this way, I'd rather not fark around making a gauge, when the car has 120k on the original FPR...eliminate the obvious then focus on the obscure. Now if I was thinking about buying a MAF just for sh!ts and giggles, that'd be different. The only thing that "seemed" to make it run better was disconnecting the MAF connector.

sorry, i was confusing your pulliing off the maf wire and it working with "someone" pulling off their fpr vacuum hose and getting it to work. my bad.

[ryan roopnarine]

may this be of some help to you.....

http://bmwe32.student.utwente.nl/sean750/fuel_pressure_regulators/FuelPressureRegulators.htm

i think that the fuel pressure in the m70 is slightly lower per bank than in the m50......so if you'd like to do the bottle test whilst your playing around with fuel lines, it won't make you any dirtier tha you are already, and it costs you nothing.

[billb]

still loading up with MAF connected. Disconnect that, and it runs open loop, but it runs. Gonna see if I can find a local MAF to "borrow" for a test run...anyone local up for that?

Bret, you don't happen to have any down yonder do you?

[billb]

$85 delivered to my door. Who knows how long it will last, but heck, it might get us through a few more years (or not...who knows?)

So, in summary:
Stumble at idle, followed by CEL coming on briefly while driving 30-45 mph, followed by just wouldn't idle (wild surging), rich running, and code 1222 with CEL lit fully, all in a span of about 30 miles.

Checked: all sensors, all checked okay (even MAF); all vacuum hoses (replaced a few suspect with no improvement); O2 sensor (checked old one and it was working, but put new one in regardless); all relays (working properly); FPR (replaced); intake manifold gaskets (replaced); throttle body gasket (good, no need to replace); injectors (clean, sealed); expansion tank (good, no cracks, solid lines)

In the end, it took the good nature of ScottyWM to let me borrow his MAF and check that one time for sure before plunking down cash on a MAF or DME. It turned out to be the MAF.

Total cost:
O2 sensor, intake gaskets, idle air snorkel hose connector: $77.44
Fuel pressure regulator: $63.09
Used MAF: $85.00

$225.53

Brand new MAF: $300

So I learned a few things...and my O2 sensor, FPR, and intake gaskets are good for another 60k+ miles.

Thanks everyone for their help troubleshooting. Ginger's back in action.

[billb]

and in the process I swapped the original chip back in. I told Wifey she could go back to 89 octane with the stock chip in it. She said "Actually, where I fill up, they charge the same price for premium as mid-grade, so we could put the chip back in." I can't believe she was actually making an argument in support of reinstalling the EAT chip!! I have succeeded in bringing her over to the joy of performance sedans! That chip goes back in next week when I get back from the coast!

And here I am thinking of taking my chip out of my 318iS, wondering if I can get gas mileage up a bit...