<paranoid alert!>
Is it possible to go into the ECU programming and shut down the system's ability to "throw codes"?
I'll explain later, but just want to know if this is possible.
</ paranoid>

 

Not quite sure of your term "throw codes" - but you can clear any error codes that are stored in the DME by using any readily available OBDII code reader. Preventing it from generating and storing the codes would not be possible as many of these DTC codes are generated by modules other than the DME.

 

Murmini, thank you for the reply, but I am looking for "insider info" from someone who works at a dealership. I will gladly explain my request by PM if you are interested.

 

Sure... please do.

 

no, you can't stop the dme from generating codes. theres no way to do it that i know of using the bmw diag. equipment.(gt1, displus)

if any aftermarket company has some kind of program like that(which i've not heard of) then you can try that. what are you trying to do???

 

no, you can't stop the dme from generating codes. theres no way to do it that i know of using the bmw diag. equipment.(gt1, displus)

if any aftermarket company has some kind of program like that(which i've not heard of) then you can try that. what are you trying to do???

 

Joey, I was hoping you would see this. Not trying to do; trying to undo. My MINI is running like cr@p, missing, hard starting, and not showing any codes at all. Dealer seems helpless to diagnose, as they have nowhere to start looking. I and they are baffled and frustrated.

 

hummm thats weird. what exactly is it doing??? please expalin as best possible. when did it start happening? what weather? runing conditions?

 

Starting ~2 weeks ago, rough idle, feels like missing at mid-range RPM (2800-4000),
Vibration through pedals at same range. Dealer had it all day Tuesday, reflashed and cleared adaptive (memory?) something-or-other. Weds thru now, very hard cold-start (have to go thru 3 starting cycles before it will run on it's own), still have same roughness and missing. Exhaust shakes violently at idle.
Temps have been in the 40s-50s in the AM, 60s-70s in the afternoon.

 

did the dealer do a fuel test?

 

Doubt that would be helpful, as I go thru 3 tanks a week. Gas from multiple stations, not always the same (but all top tier). Just finishing up a tank with Techron in it at their suggestion. They've been playing with it all day now, and still no answers. Want me to come back and leave it overnight, so they can experience the cold-start first hand.

 

Some problems aren't diagnosed by the computer...sometimes you have to do it the old fashioned way. A bad mass air meter made similar symptoms in an 89 Camaro V6 for me...no codes, but ran very badly. The computer is excellent at detecting a sensor that is shorted or open circuit. It'll also pick up a sensor giving data that is well outside normal operating range such as coolant temp of -40 while intake air temp is well above that. It sometimes doesn't pick up a sensor that it transmitting data that is within its operating range, but nevertheless incorrect.

Hook up a scan tool and see if any of the parameters is way out of the ballpark (this is where experience is useful). Also look for vacuum leaks, bad spark plugs, bad coil packs, bad plug wires, etc. Are you making the proper amount of boost at any given rpm and throttle setting? (I noticed you had a boost gauge). Do all cylinders have mostly equal compression?

Modern mechanics rely on the computer too much....

Rawhyde

 

Rawhyde, thank you for getting to the meat of the problem. Too much reliance on the code reader, and not enough mechanical smarts.
Plugs, wires and coil are all new this week. No change. Low boost( max 7.5lbs at redline/WOT). Compression? I dunno. Can't get the dealer to check the things I want checked.
Since I am having major runability problems, and no CEL/codes, I suggested that they test the DME by pulling a spark plug wire and seeing if a misfire code popped up. Would they do it? No. Claimed that it would prove nothing. They would rather spend 7 hours chasing ghosts (and they think they are going to charge me for diagnostic time) and have me come back a 3rd time
for another round of "can't duplicate". I am really getting fed up with the dealer service. If they can't diagnose a runability problem, what good are they? The only thing that keeps me going back is the 8yr/80k mile emissions warranty. If this a bad DME, I ain't paying for it.

 

A gasoline IC engine requires fuel, air and spark. Since you've already addressed spark, then two other possibilities come to mind.

1. A fuel injector is not working properly, either due to debris or a mechanical/electrical problem.

2. A valve is cracked, providing an escape route for compressed air and fuel during the compression stroke. This is pretty extreme, but I've seen it happen at work. The engine ran rough, with a cold exhaust port, and eventually ventilated in dramatic fashion. Very dramatic fashion. (I still have the big end of the conn rod that was pitched out on the test cell floor. That's the only time I've seen that end of the rod escape a block. It tore the rod in half and broke all the rod capscrews). I have not heard of this happening with a Mini, but it is another possible source of the symptoms that would not throw a code. A compression check should indicate if there is a problem with a cylinder.

Good luck.

Scott
90SM

 

How many miles do you have? Is the 7.5 psi of boost correct? Is the exhaust note lower/duller sounding in the range that it vibrates? Does it vibrate right after start up or after 20-30 minutes of driving?

My first thoughts are intake/exhaust leak or coolant temp sensor. Any other info to share?

 

54k miles. Correct? How do you judge? I'm seeing 7.5 on the gauge, where before I've seen 10. Exhaust does sound deeper/raspier and now pops a lot on decelleration. Shaking is usually after car has warmed up. Vibration while driving comes on at a certain RPM and is consistant; I can move in and out of it at will by feathering throttle.

 

Joey, (and Scott,too) you were right, man! 55% leakdown on cyls 3 & 4. Pulling the head now to see what's up. Cyl 3 leaking on intake, 4 on exhaust.
That would certainly explain the rough idle!
Oh, and they're covering the head R&R under warranty!

 

wow 55% leakdown is a lot. i'm glad i got to talk to you, sorry about the delay but with the new baby and all... anyways let us know what happenss next, good luck!

 

yes it's possible...especially if you only have a ball.

 

Wait.. what??? what are you talking about?

 

Got the car back yesterday with a shiny new head. Went for a club run today and....nothing has changed. Still have the rough "sputtery" idle, Still have the bog at 3200RPM. And I seem to have picked up a "yo-yo". And a "whooosh" at ~4k on hard acceleration.
I am getting seriously tired of dealing with this.
Reality check: could my $45 "one-ball" mod have anything to do with this? The exhaust rattles/ buzzes/ is generally annoying just about all of the time.