E39-525 multile misfiring codes ; solution?

[xlvvrk]

Misfire Problems Help Please.My mechanic made me change the computer ECU/DCM unit after getting what he calls faulty codes...
and he found nothing wrong with coils, plugs, wires , injectors..... and therefore blames the ecu.
Car misfires badly with even fuel cut off when HOT, it's running fine for 20 minutes when cold, .
Will continue to misfire until I shut the car off, then it will run fine after 1 minute of rest. ( resetting ???0.
the codes it comes up with + 29 30 31 ignition cil 1 3 and 5.
and : (210) ZSR Fault at more than 2 cylinders.

really desperated as nobody can tell me what's wrong .
MAF ?
TPS?
Crank Sensor?
Coils?
PLEASE IF ANYBODY SOLVES THIS PROBLEM ??? let me know.
tx.
email xlvvrk@Hotmail.com

- - - Updated - - -

please note it's a 525 - YEAR 2003- 150K MILES - 6 C IL IN LINE.

[geargrinder]

DUDE. WRONG PLACE. You should have a mod tow this to the main forum. Perfectly fine thread start but "Common Problems and DIY etc." is for "how to DIY posts", and NOT for you to post about your problem.

This is not an uncommon problem. Calm the eff down and take a few deep breaths.

Things that can cause multiple-misfires are:
1. vacuum leaks
2. leaky valve cover gaskets causing oil to short out the plugs
3. bad plugs
4. bad coils
5. then a bunch of other possibilities like fuel or O2's or MAF but only after looking at the ones above first
6. and then some more rarer things
7. ????
8. Profit
9. Ham sandwich on rye with extra mayonaisse
10. In the form of a question: "Who is Robert Mugabi?"
11. A stitch in time saves nine
12. Rutabaga
13. "And she's buying a Stairway to Heaven"
....
50. NOT EVER THE ECU IS THE PROBLEM EVER.

OK that's an exaggeration. If your ECU got contaminated with water or smashed by a hammer it MIGHT be a problem, like 1 time out of 1000. But its almost definitely NOT the problem.

Plus, you can't just swap DME's (BMW calls the ECU "DME"... "Digital Motor Electronics" more or less...) into the car willy-nilly. Its got elaborate immobilizorz tech to keep you from doing that. You toss a used DME in and it won't remotely think about starting unless you have the flash in it altered to either 1. disable the immob tech ("EWS" in BMW terms), or 2. 'virginize' it to then re-pair it to your car .

But really. The DME's almost never go bad. Sounds like you don't have a real BMW mechanic. The key to diagnosing this properly is using good BMW software or at least a BMW-specific proprietary scanner that can read live values and get full proper codes and not just P codes. What are the fuel trims the engine is showing now? Normally a misfiring car that doesn't have cylinder specific coil/plug spark problems will show super high or low trims indicating either a vac leak or sensor (O2 or MAF). Need to gather more information, "replace the ECU" is definitely a sign the guy probably is incompetent to work on the car.

[BMtroulbewe]

I would check the wire harness first. Also how old is the battery on your car? They can fry up electronics especaily if you jump start too often.

[xlvvrk]

tx for the quick replies ! If the problem is " not in common", I'd say it has its place here...LOL.
I agree that my mechanic is not a BMW expert, and gladly limits himself to replace the parts sorted out by the DCM....
and does not want to deal with electronics and certainly not remapping or swapping ecu's...
The strange thing is , the problem ( heavy misfiring and fuel cut off) only occurs when hot and after slowing down/ stopping and getting it to go again .
You can feel it's only going on 3 cylinders...... and no way to rev it up!
The car is just undrivable !
I already checked for leaks.. nothing except the little tube for the 2nd air pump that 's broken.
I do not understand how spark plugs, cables ,coils and injectors can be working perfectly and not at all 2 seconds after....

Q: are o2 sensors really that sensible to heat that they can't work at all when hot, while they seem to reset after shutting down?????
=>
If it is a common problem on E39's, what is my solution?
I read people changed every sensor without any result.
I really thank anybody making me understand and SOLVE the problem.
thanks.
xlvvrk

[shogun]

Moved to main forum

[geargrinder]

If it is a common problem on E39's, what is my solution?
I read people changed every sensor without any result.

Brother, its not that easy as "here is your solution!".

It is NOT "every time you have multiple misfire errors the answer = XXXX!"

I gave you a list (and then some jokes) of possible things the "multiple misfires" can be caused by.

Mistakes that people make when trying to diagnose this (I'm gonna give you more lists!):
1. Using mechanics that don't know the motors at all
2. Throwing parts at it randomly (aka your "replaced all sensors without any result")
3. Thinking they've checked stuff like vac leaks when they haven't

The vast majority of the threads you see end up being some assortment of those first 5 things, things then some other rare causes. Most of the time when a guy never posts back an answer its because his car got fixed by finding one of those things and as soon as the car worked OK he didn't give a crap about his thread anymore so he didn't post a final answer.

"You checked for leaks". Did you now. OK how did you do that. Did you use a smoke tester? Or did you disassemble all the intake bits and inspect them all? Or did you "gee kinda looked around and there aren't any gaping holes sorta well except for that big SAP pipe thats broken"... There are tons of stories of vac leaks that people only found through hard work and/or smoke testers. Now I could give you more stuff to look into like CCV or DISA failures but then you're in "random parts" territory. Lets do some diagnosis first.

OK so your one specific clue seems to be misfiring when hot... things that can go wrong when the engine is hot:
1. blown headgasket
2. injectors can fail when hot only (have seen this myself although your 'multiple cylinders' situation suggests its not just 1 or 2 injectors and many failing at once is highly unlikely)
3. certain vacuum leaks (I once had a car that would only leak at a crack when the rubber for the intake got hot and soft...)
4. various sensor electrical failures because the sensor somehow is warping/flexing to cause the failure only when hot (or cold)
5. other electrical failures where shorts only have a big effect when things get hot enough.. (either sensors that only fail when hot, or, I've seen cars with bare-wires in a harness but they tended to only touch when the engine was hot and the harness flexed around, so the guy was looking for some other magic connection with temperature...)

You haven't given hardly any info for an internet diagnosis. Things that woudl be helpful to know:
- No signs of blown-headgasket - not overheating or it didn't overheat recently before the problem showed up?
- What other problems does the car have? Cracked SAP pipe you say... I'm guessing its a bit of a run down beater otherwise as well?
- What do the fuel trims look like in the ECU? Are there any fuel trim codes? What other codes does the engine show? I'm gonna bet its not only the multiple-misfire code.
- What engine temperature does the ECU see when reading 'live values' with a scanner/software? If the engine temp sensor is failing when hot then it can cause stuff like this.
- Do the MAF readings look plausible when the car is warmed up?

All that stuff comes from having a proper BMW scanner or computer w/ BMW proprietary software & cable but it will really make diagnosis a hell of a lot easier,. instead of just "firing the parts cannon"/.