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Discussion Starter · #1 ·
Hi!

Im new at this place, and not very good at english, so bear with me please. :)

I have searched for my problem, but I can't find anyone describing the same problem and having the same error in the DME unit...

Okay, here's the fact.

Car:
BMW 523i ´97 (e39) Swedish/European model.

Problem:
Missfire (or something similar?!) during warm engine and medium to heavy load. From about 700rpm up to approx 2000rpm. It feels like its running on 4 cylinders... Reduced torque and power. No problem if I hit the throttle carefully.

I installed Carsoft 6.5.06 today and ran a test on the DME it gave me:
Text Font Line Number Document


Comes back directly after erasing it...

Is Oxygen Sensor the same as Lambda sond? and I assume that Carsoft refers to the sensor on the exhaustmanifold, closest to the torpedowall?

When I checked the Live Data, I found that "Signal Lambda Probe Heating 1" value was going between 0.6-4.8 volt, BUT "Signal Lambda Probe Heating 2" value was steady on 4.8?!
Text Font Line Screenshot Technology


I also noticed som difference between Cylinderbank 1 & 2
Text Font Line Screenshot Technology


BUT, the car still tells me that Lambda Regulator is active for both banks
Text Font Line Screenshot Technology


Im confused....

And as far as I can see, there is no errorcodes for missfire?! Im a first time user of Carsoft, but I don't think I've done something wrong?

Can i drive with the Carsoft plugged in and see anything while driving? Like missfire?

I have recently changed the plugs, but I had the problem before the change.

Hope someone can help me... :cry:

Cheers!

//Anders.
 

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Welcome to the Fest. I'll post just to help keep your thread near the top and in view. Don't worry about your English, you're using it better than a lot of native speakers here.

Hopefully someone will step in to guide you with the misfires and CarSoft clues.

You could have any number of problems.

Spark: You say you've changed the plugs. Are the coils okay?

Air: Does your car have a MAF sensor in the air intake? Could be dirty (but removing and cleaning it has to be done with care and MAF cleaner).

Fuel: How old is your fuel filter?

How old are the pre-cat O2 sensors (How many km or years of use?)
 

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Freude am Fahren
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:lol::lol: Torpedowall. Did you use a translation tool by any chance?

After 160,000 km, the O2 sensors are due for replacement, but I don't think that the misfire is caused by the O2 sensor. I think that O2 Active means that the car is told to use them. In some markets the O2 is not installed. Because the O2 sensor problem is the heating element, maybe it's a broken wire or a universal O2 sensor that was installed and not hooked up entirely correctly.

Was there any oil leaking around the plugs? A leaking valve cover gasket can cause misfires.

The misfire could be due to a lot of reasons, and it's frustrating that there aren't more codes to be extracted from the computer. I would start by cleaning the Mass Air Flow sensor (right behind the air filter, but be very careful and don't touch it, just spray it with MAF cleaner) and possibly replacing the fuel filter.

Maybe DISA can cause this problem?
 

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Seek to understand,^Value
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I don't know what your problem is but everything so far listed by others is in this diagnosis thread.
- How to diagnose a BMW E39 engine misfire (1) & a cold-engine intermittent misfire (1)

You might want to try it and let us know how it works for you.

The goal is for you to try what it says, and then report back how it went so that we can improve it each time.
 

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Discussion Starter · #6 ·
As far as i can see, the car does not complain about the coils. No fault/error code in Carsoft.

I've changed the fuelfilter a couple of days ago. No differance...

I will check the MAF sensor. But I've never heard of a special MAF-cleaner? Is it okay to use like, breakcleaner?

No leaks around the gasket. Will check further for oil around it.

The car has about 240 000km on the tacho, and I don't think any O2 sensors have been replaced... I will also check it for broken wires. Actually I read on some other forum that a broken o2 sensor actually CAN be the reason for strange misfirebehaviour... :) But this hasn't happened to me before so I don't know.


I started to read that guide, but I didn't think it fitted my problem, considering the faultcode I got when reading the car. That's why I created this post.

But thanks guys for the help so far. :)

And by the way, my car is a 523i... NOT a 532i! ;)
 

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I am not certain but I think the chemistry for the MAF cleaner is different than that used for brakes. Do not use brake cleaner unless you are certain it's the same. I believe the MAF cleaner is mostly hexane. Here's a data sheet for a very common MAF cleaner sold here.

www.crcindustries.com/faxdocs/msds/5110.pdf

One obvious thing I forgot to mention yesterday is that you should check your air-intake boot and other vacuum tubing that could be leaky. Extra air allowed into the manifold would create a lean condition.
 

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Discussion Starter · #8 ·
We have CRC in Sweden as well, so that is a great tip! :)
I'll check for it tomorrow. in Sweden it's called "Air Sensor cleaner".

I'll also buy a can of startergas and check for leaks in hoses and so on...
 

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Seek to understand,^Value
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I think most of us figure the MAF is so expensive, and so fragile, that we'd better use whatever is sold specifically for cleaining MAFs.

Here is what I listed in the best links thread for cleaning:
- MAF CLOGS: the mass air flow sensor (MAF) and idle control valve (ICV) require periodic cleaning (1) (2)

In the second of those threads, is this Material Data Sheet for MAF cleaner (it's hexane):
crc_maf_mds.pdf (49.7 KB, 36 views)

Dunno if these help (didn't check the links myself); but others posted these in the best links thread:
- Inspection II part II: Cleaning MAF & replacing power steering fluid
MAF and CPS replacement (video)
MAF boot replacement (fix for rough idle, intermittent loss of power)
MAF replacement using Range Rover part
MAF testing
MAF cleaning
Mass Air Flow Sensor (MAF) cleaning and Camshaft Position Sensor (CPS) R&R
MAF Removal and Cleaning (2000 540i and 2001 525i)
O2 sensor & MAF replacement (540 M62)
etc.

 

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Discussion Starter · #11 ·
Okay, here's an update.
I bought the spray and cleaned the MAF sensor. Looked nice and clean, but I sprayed it with about half a bottle from every possible angle.
I also got some contactspray, so I removed all the connectors from the coils and sprayed some in every one. Did the same thing with the injectors. And the vanosconnector. And every other connector I could find. :) The lambdaconnectors as well.

I inspected the MAF-boot and no problems there. It might have some beginning of drying up between two pf the ribs, but nothing serious yet.

I sprayed carburatorcleaner (startgas actually) and I emptied a whole bottle all over the engine, but I didn't get it to raise the idle even 1 rpm! Steady as a rock... Also I couldn't find any dried hoses or similar.

I looked into the boot as I had removed the MAF, and it was 200% clean in there... ! I know that on other cars that I have been inspecting, it has been a lot of oil deposits (or whatever you guys call it)

I got the car back together and started up. Connected Carsoft 6.5 and erased all the errors.
As far as I can see, I've got rid of the error 55, o2 sensor. But I'll check later today if its back.

BUT... the car STILL makes these very irritating "loss of power"-tics... Low RMP:s and medium to hard load... :(

The only errors Carsoft gives me now is
"40 Thermical Oil Level Sensor" from the LCM (?!?!)
and
"22 Auxiliary-fan relay" from the Airco module, and I don't think neither of them has anything to do with my problem... ;)

When I look at live data, the oxygensensors are behaving properly again... Don't know if it's because I've given it a round with the contactspray or what, but apparently it worked.

I don't have any DISA-valve on my European M52 right? Just so I can stop looking for it! :)
 

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Discussion Starter · #13 ·
Just as I supposed... :) but hey, one less thing to worry about! ;)
Sooooo..... That leaves us only to one last problem... What's the fault!?!

IF theres any problem with any of the coils, shouldn't it give some kind of error?!
 

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I am not sure whether failing coils will generate a fault code.

What about your cam position sensor(s) and the Vanos system? Vanos seals can deteriorate without leaving fault codes, but I haven't heard of them causing the kind of power-band loss you described.
 

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Discussion Starter · #15 ·
I've been thinking about the Vanos seal, but as you said, I don't think it can cause that kind of trouble...
Wouldn't problem with the cam positioning sensor leave a fault code? At least that's what I thaught...

As a little off topic, I just want to mention that just now as we speak, Im sitting in a hotel down in Munich. Home of our beloved cars. :) Unfortunately I don't have the time to visit BMW's museum or factory... :( Im here to buy a 335dT ´07 fully M equiped. :p
Buuuuut I still need to get my 523i straighten out so I can sell it. :)
 

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What about the crankcase ventilation valve or idle control valve?

Have you ever tried using a fuel system cleaner like Techron, or SeaFoam poured (dripped) directly into one of the vacuum tubes (with engine running) that will carry the fluid into the intake manifold to clean it? I reluctantly mention this (some people are not sold on these treatments and believe they could cause harm if applied the wrong way). SeaFoam has its believers and haters.
 

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Discussion Starter · #17 ·
Crankcase ventilation looks fine, but I guess I could dig a little deeper into that. The idle control valve can't cause misfiring like this I guess?

We don't have any of those treatments in sweden... We have STP injectorcleaner, but that is the closest I get I suppose... Will try that aswell.
 
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