E46 Fanatics Forum banner
41 - 52 of 52 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #42 · (Edited)
-SOLVED-
The issue was an extra o-ring in the crankshaft position sensor slot. This problem was persistent when I bought the vehicle and one of the first things I did was replace the crank sensor, but the one I pulled out had an o-ring on it so I didn't think to search for an o-ring that was stuck in the sensor slot before installing the new sensor. 2.5 years later and I finally found the issue. Now she runs like new and I know the SULEV swap was 100% successful! Cheers to you Fanatics!

Please read this post carefully and keep in mind that this issue existed when the car was in stock condition and is not a result of any modifications listed below.

TLDR: RPM drops, rich trims, and misfire: erratic Calculated Load Values: fuel pressure good; compression good: most relevant components tested and/or replaced. No engine light, no confirmed trouble codes; unknown cause.

Check out this dropbox for all the juicy bits.

Hello, hope y'all are well today. My name is Kevin, and I drive a 2003 BMW 325ci m56b25 automatic that suffers from an unknown cause. This car has been looked at once by an independent mechanic and twice by the BMW service center with no success. I am a capable mechanic and have many tools and software at my disposal including ISTA and OBDfusion among others so please ask me to provide any screengrabs, OBS recordings, or spreadsheet data that you think might benefit the cause and crack this case.

The issue here, in its simplest form, is that the vehicle undergoes RPM fluctuations or "bounces" that lead to power loss while the engine is under load. This failure gets consistently worse as engine RPM increase until total power loss is experienced somewhere about 5 thousand RPM. Here are a few things to note:

  1. The vehicle must fully warm up to operating temperature before being driven. While the engine is cold the symptoms are nearly immobilizing and the car will likely go into limp mode until restarting. After warming up, the symptoms subside considerably and the car can be driven normally with no risk of limp mode.
  2. Oftentimes a brief flash from the charging indicator light will accompany these RPM bounces. I believe this to be another symptom and not a cause. The battery and alternator are both new.
  3. Slopes and hills make the problem significantly worse; cold night air makes it significantly better.
  4. Rich trims at times below -30; fuel pressure good and injectors replaced.
The evidence I do have is paltry. Once, and only once, the cluster beeped and the DSC/BRAKE lights illuminated when I forced the engine into high RPM on the Interstate. Immediately all the power issues seemed to vanish and the engine smoothed out a lot. ISTA pulls a new code: 3C1D (P0335), which relates to DME: Crankshaft sensor: signal - Engine speed signal implausible. The obvious implication here is that this is crankshaft sensor-related, however, replacing both the sensor and wiring harness did nothing. Anyway, why would the sensor not fail during crank or idle? Maybe not crank sensor-related after all.

The shop foreman at the BMW service center was under the impression the car was acting as if it had faulty software/fuel mapping or high exhaust backpressure/intake restriction. The tech there suggested I replace my EKPS module and MAF sensor that was also related to some codes he found. The independent shop seemed to think I had bad fuel injectors or a faulty MAF sensor. EKPS, MAF, and fuel injectors were all replaced yet their codes are still present.

All relevant repair work is categorized here into 3 main sections: Fuel, Engine, and Electrical. This info may overlap.

Fuel

If you're a keen observer you may have noticed by now that I have an m56 engine model. This is BMW's e46 SULEV that was specifically designed to meet emissions requirements in several states and has a unique fuel system. I have modified this system as outlined below to make diagnosis easier and in some cases just plain possible.
  • SULEV fuel tank replaced with M3 variant fuel tank, pump, filter, and pressure regulator. I have upgraded the fuel pump to AEM 320lph and verified the system is functioning at 5 bar.
  • The EKPS module has been replaced with no improvement. I have 2 codes relating to the EKPS module. They are EKPS: Control current too high and EKPS: Pump speed too low. Replacing the module did not resolve these codes.
  • Evaporative emissions system replaced with NON-SULEV components.
  • Fuel injectors and seals were replaced with stock m56 for consistency.
Engine
  • Intake/Exhaust
    • Disa valve and seal replaced; checked for vacuum.
    • Intake boots checked for cracks; open vacuum ports sealed with plugs.
    • SAP removed and catless headers installed; DME EU2 flashed by Kassel.
    • MAF and both Camshaft sensors were replaced.
    • Post-cat O2 sensors removed; pre-cat O2 sensors absolved by unplugging.
    • The throttle body and ICV were replaced with known working ones. Swapped back.
  • Ignition
    • Replaced all 6 ignition coils and spark plugs.
    • DME CHECKSUM error caused no ignition condition; repaired by RPM Motorsport.
    • New alternator; running voltage 14.3 volts.
  • Mechanical
    • Dual Vanos seals have been replaced and both solenoids were tested as good.
    • New Crankcase Vent Valve membrane and vent cap installed.
    • Compression tested 170 psi/cylinder with a variance of 10.
Electrical
  • New battery and Alternator.
  • All fuses were tested and the DME relay was swapped with the fuel pump relay.
  • Fixed some frayed wiring on the Crankshaft sensor harness.
  • Monitored throttle body and accelerator pedal values in ISTA; seemed OK.
  • Disconnected both O2 sensors and ran vehicle with no improvement.
  • Tested pedal and throttle potentiometer values in ISTA; seemed healthy.

Check out my dropbox for videos and recordings that show the issue firsthand, as well as spreadsheet data and live data captures. If there's any data I can gather for you that you think might offer fresh insight then please feel free to ask in the comments below. This car really wants to stretch its legs. You can tell it has a solid foundation and sturdy heart when you drive it but something is holding it back. Most people who work on this car including myself agree: this problem should be easier than it is. There are just not that many things that can cause this kind of problem, but at this point, I am out of ideas. I have a feeling the solution will be something relatively simple because the engine feels very healthy and powerful, but whatever is preventing the engine from breathing properly has been incredibly elusive.

You guys are the friggin' best. Thanks for reading and God bless.
 

·
Registered
Joined
·
13 Posts
Did all of this happen before or after the kassel tune? They could have dme setup for a regular non sulev ms45.1 car. With the different injectors the tunes are probably very different.

This was what I found searching on realoem and BMW fans.

SULEV Programmed DME part#:12 14 7 561 534 BMW-Fans program number SULEV: 7 561 534

Regular Programmed DME part#:12 14 7 543 012 BMW-Fans program number non-SULEV: 7 543 012

As you can the part numbers are different...which means the tunes are different

If I was in your shoes I would ditch the MS45.1 and convert the car to ms43. I have a tuner who is super helpful and does remote tuning if you want to PM me. He could also maybe fix the ms45.1 in your car. I'm not saying kassel is bad, but I've had some issues in the past with them and I now chose to use someone else.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #46 ·
Hey, thanks for the responses.

It's not water in the gas tank.

2 years ago the DME was repaired for a RAM CHECKSUM ERROR by RPM Motorsport that caused a no-start condition. These problems existed even before that. Kassel did the EU2 tune maybe 6 months ago and everything seemed to go perfectly. I'm not interested in swapping to an ms43 on this particular vehicle at this time, but if the DME is the cause of the issue here then there shouldn't there be a way to verify this? Can I just crosscheck the software version of my DME to the appropriate software version for an m56 ms45.1? I asked the dealer to do this but I don't think they did. I'm not opposed to replacing the DME if it comes down to it but I'd like at least some evidence that points to it as being the root cause.
 

·
Registered
2000 E46 323i, 3.0L and 2.0L Z3's
Joined
·
1,280 Posts
I do love a good mystery. Unfortunately, I'm packing for a 4 day road trip, so will not have the 2 to 3 hours to spread sheet your logs for about 5 days. So, everyone else can have a head start on solving this one.

Could you please run the below log and post it in your drop box. After reading your long #1 post, there is something I want to check.

Rev Rise Test
Run your normal OBD Fusion log. Hot engine and Cat’s, stationary car. The test is best done just after a drive. Slowly raise the rev's of the engine up from idle to around 3,000 rpm. I mean slowly. It should take you 3-4 minutes to do this test.

It takes some skill to do this test due to the lightly loaded engine. A little throttle change results in a large rev change. Don’t run up and down the rev range getting used to the control. If you stuff up the first part of the test getting used to controlling the small rev changes, then redo the test.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #48 ·
I do love a good mystery. Unfortunately, I'm packing for a 4 day road trip, so will not have the 2 to 3 hours to spread sheet your logs for about 5 days. So, everyone else can have a head start on solving this one.

Could you please run the below log and post it in your drop box. After reading your long #1 post, there is something I want to check.

Rev Rise Test
Run your normal OBD Fusion log. Hot engine and Cat’s, stationary car. The test is best done just after a drive. Slowly raise the rev's of the engine up from idle to around 3,000 rpm. I mean slowly. It should take you 3-4 minutes to do this test.

It takes some skill to do this test due to the lightly loaded engine. A little throttle change results in a large rev change. Don’t run up and down the rev range getting used to the control. If you stuff up the first part of the test getting used to controlling the small rev changes, then redo the test.
Here's a link to the Rev Rise Test.
 

·
Registered
2000 E46 323i, 3.0L and 2.0L Z3's
Joined
·
1,280 Posts
Thank you for posting the Rev-Rise Log.

I've been through your logs. Lots of very interesting things going on.

Need a bit more data.
  • Can you please unplug the MAF and while it is unplugged run the hot idle and highway cruise logs and post the links.
  • What make of MAF did you fit when you replaced the MAF?

Time invested so far is 2 1/2 hours.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #50 ·
Thank you for posting the Rev-Rise Log.

I've been through your logs. Lots of very interesting things going on.

Need a bit more data.
  • Can you please unplug the MAF and while it is unplugged run the hot idle and highway cruise logs and post the links.
  • What make of MAF did you fit when you replaced the MAF?

Time invested so far is 2 1/2 hours.
Hey mate, I got some new tires and I'm back on the road!

More good news is I grabbed a warm idle log with the MAF unplugged. You can find and compare that here.

Unfortunately, however, I was unable to get a highway cruise log with the MAF unplugged. It seems the car runs a fair bit worse with the MAF unplugged and I cannot get up to highway speeds whatsoever without the engine going into self-destruct mode. Same problems, just much worse.

The MAF I purchased is this VDO 5WK9642Z M56 from Rockauto.

Cheers!
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #52 ·
This issue has been solved and this thread can now be closed. Much thanks, everybody! I'll be contributing the knowledge I have gained throughout this project back into the E46 community going forward. Much of this knowledge is relatively esoteric and relates to things such as fine details about the SULEV fuel system and evaporative emissions system, and programming/coding the ms45.1 DME.
 
41 - 52 of 52 Posts
Top