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Discussion Starter · #1 ·
Just took a short drive down the street, and saw "Engine Fail Safe" on dash and drove it straight home. Shut off, restarted and saw same warning. Went and got OBDII code reader out, and no codes, active or pending. Restarted engine, no more warning, went for a short drive of a few miles, car drove just fine. But on the last part of the trip home, the engine died at a stop light. I have NEVER had the engine do this for it's entire 183k life. Restarted just fine, drove it home and parked it.

Anyone got an idea what is going on?
Planning to take to to BMW Seattle.
 

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Discussion Starter · #3 · (Edited)
Does your "code reader" access pending codes?
Yes, as I stated, no active or pending codes shown.

BTW, I just went out to check again, and still no codes at all, but when I gently increase the throttle, the rpms do not smoothly increase, they pulsate up and down.

My ELM 327 scanner also reads live data....but I am not experienced enough to interpet that information.
 

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Sorry - I failed to carefully read your post.

The long-term and short-term fuel trim numbers may offer a clue. The STFT will vary a good bit when driving, but LTFT s/b pretty stable, and the ideal range for both parameters is +/-5%.

One article in Motor magazine suggests running the engine at 1500 and 2500, and observing these two parameters. But, you should also observe the numbers at the point when the engine begins to falter.

Coolant temperature is another parameter to observe, and s/b 100-110 deg C. Ignition timing is also available.

Is there some reason you prefer the dealer to a well-regarded indie? You can find good indies in your area by subscribing to Checkbook.org.
 

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Discussion Starter · #5 · (Edited)
Though expensive, BMW Seattle offers excellent service and accurate diagnosis. I also can get ride home/pick up, or a loaner car.

The local race shop that has been working on my suspension does have some more sophisticated diagnostic gear and has offerred to take a look at it. I'll take them up on it before running it to the dealer...

One additional piece of background information: About three years ago, I got a similar "pulsing" of engine RPMs when pressing on the gas pedal...I don't recall seeing an "engine fail safe" warning or not....but I did get a "Service Engine Soon" warning. When I scanned the codes, I had an active code for the throttle position sensor. I recorded the P code and cleared it. It did not return, nor did the symptoms, but it worried me, and I immediately ordered a replacement gas pedal (which is where the throttle position sensor resides on 2001-2003 540s). Frustrating replacement, as I later discovered during installation that BMW revised the gas pedal, and in so doing, also changed the mounting plate fixed to the floor it attaches to. I couldn't get the new pedal to fit...then figured out I also needed a new mounting plate to go with the new style pedal.

I have been advised there is another throttle position sensor on the throttle plate on the engine...makes sense, since it has to receive the info from the gas pedal. The shop says they will be looking at that on their diagnostic gear for proper function.
 

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Yes, there are two potentiometers. As I recall, they track opposite (one goes up, one goes down). The DME tracks their position as a feedback of throttle position. This assembly must also be replaced if defective; not serviceable.

I sure do like my throttle cable and ICV.
 

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Discussion Starter · #7 ·
So the shop confirmed an intermittent issue with the throttle plate potentiometer. It is an assembly, so the entire unit needs to be swapped and calibrated. About $300 for the part, and I will probably be in for a couple hours for diagnostic time and replacement. Throttle cables have plenty of issues of their own...so a toss up in my book...

I am curious if my previous problem three years ago was not the pedal, but the throttle plate?
 

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There's stuff about trans failsafe but not much about engine failsafe in the bestlinks (oh, the horror).

A subsequent 'advanced' E39 title-only search for "engine failsafe" only came up with 23 threads.

The top three (by number of views are the following):

Q: So that all benefit, which thread should we make the canonical engine failsafe thread so that we can update that one thread as new information comes in?

Should it be this thread itself?


EDIT: I added the following, for now, to the bestlinks (pending the results of this query to the users):
- How to diagnose the E39 engine failsafe prog cluster error message (1) (2) (3) (4)
 

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Discussion Starter · #9 ·
Picked up the car, all fixed, about $500 with tax. This is the first time I was unable to diagnose a problem myself, with a standard OBDII code reader, since no active or pending codes were stored. The shop's diagnostic software could pick up the proprietary BMW info immediately. I guess here is where PA Soft or something has it's advantages. Or maybe if I had driven the car some more I could have tripped a code?
 

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Discussion Starter · #11 · (Edited)
Can you post the PN of the item(s) replaced?
Dealer or Indie?
I'm surprised you can replace the throttle assemble (EML) for only $500.
Independant. 1.5 hours labor, plus part $306 and tax. $499.32 out the door.

The oem VDO part can be obtained online for $225 from autohausas.com with free shipping.
part number 13541435959
enter it here for the price and description: http://www.autohausaz.com/
 

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Independant. 1.5 hours labor, plus part $306 and tax. $499.32 out the door.

The oem VDO part can be obtained online for $225 from autohausas.com with free shipping.
part number 13541435959
enter it here for the price and description: http://www.autohausaz.com/
I paid about the same about 2 or 3 years ago. However, I think I damaged it by manually moving the plate whilst cleaning the plate with throttle body cleaner.
 

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Discussion Starter · #14 ·
OK, maybe these cars won't be too expensive to fix as they age. Doesn't look like there's a core charge. Is the defective unit available for an autopsy? I'll pay shipping.
Sorry I didn't ask the shop to save it...
 

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Discussion Starter · #16 · (Edited)
+1
throttle cost is around $350 online w/o labor ( i changed my on M54 2 years ago )
500$ for all is impossibly cheap
We have different engines...I posted that you can buy the throttle assembly for $225 online with links to the source.

See post #11
 
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