M54B30 - 2004 Engine into 2003 330CI - Wiring Question

Hey guys,

I have my engine sitting in my car, tranny mounted up, now I'm onto the wiring.

This used engine came with the wiring harness attached so I figured I would use it. My question is this. There is a subtle difference in one connector in the "main brain" of the wiring harness.

My old wiring harness had 7/8 wires going into a 7/8 pin slot. The 04 harness has 3. I am assuming this is the part where the sensors talk to the computer. Was this just a simplification or complete difference.
This is the old connection, the new harness would only have 3 cables going into this slot.


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Is there anything else I need to know? Will the computer process everything correctly? Do i need to flash it? Do i need to pull all of the sensors off the engine and replace it with the 03(this would be extremely obnoxious to do with the engine already in).

Deepest apologies if this is posted elsewhere,
Thanks for your help,
John

Bump! Anyone?

Originally Posted by JohnnyZ91

Bump! Anyone?

bump, i'm also interested..

Can't really find it. It might be transmission related (auto vs manual)
I would strongly suggest to use harness that came with your ECU not the new engine.

The engine I received was from a manual car. I would potentially use my own harness but I don't know if there are any other sensors that may be different throughout the engine. I am sure this is probably not the case but it's still a risk. Thank you for your insight though, I would really like to use the 04 harness.

I got a spare harness at home. I'll try to find out where those wires go.

Thank you. Appreciate it!

Bump! I need to finish this car before the winter blows in hard.

There are several differences in the M54 after 02/2003. When was your car actually made?

The MAF is a 6 pin connector, the intake manifold does not have the air temperature sensor, the SAP uses a second MAF sensor to determine if the air pump is running.
There are also differences in the O2 sensors in the later M54 engines.

Up to 02/2003 the M54 used the MS 43 ECU, after it used a MS45 ECU.

I'm pretty sure his 2003 car and 2004 engine are both MS45. I probably would have used the old harness though. Don't see any reason whatsoever to change it unless the old one was damaged??

VIN NUMBER: WBABS53463EV90482 - Built december 02, 03 production date

Appreciate your help, if you could validate this mango that 03 and 04 engine are MS45, the 02 sensors are definitely different if that says anything.

The only reason why I didn't use the old harness is because the new one was already attached and all of the sensors were aswell. We then threw the engine in without completely validating the wiring would match up(learning experience/some of the o2 sensors were cut so I realize this till after taking the top cover off).

So where do I stand? What are my options?
1.) If I throw the old harness back on will everything be fine with the corresponding mismatches? As you stated shanneba? Or will I be blowing a ton of codes/running rough?

What does the connection in the picture I posted do? I can't figure this out, which would probably help my decision.

If I use the current harness(04) do I have to flash the ECU/buy a new one?

What is my best bet right now.

Thank you guys for posting

2003 models built up to 02/2003 still used the MS43 ECU (My car was built in 02/2003)
Starting with production in March 2003 the ECU changed to the MS45 (also the "performance package' was introduced)


VIN NUMBER: WBABS53463EV90482 - Built 2002-12-09

http://www.rubmw.ru/vincode/eng/

Your original car should have had a MS43 ECU, only those built from 03/2003 on have the MS45.

You could use your old harness, changing the O2 sensors from the old engine to the newer one.
You would also have to at least remove the Intake Air temp sensor out of the old engine intake manifold, remove the plug in the new engine's intake manifold and install the sensor.
Maybe more.....

For wiring diagrams check here:
BMW wiring diagrams - http://wds.spaghetticoder.org/en/e46/
http://www.bmw-planet.com/diagrams/r.../e46/index.htm

Thanks for the help!

What about using the new harness? and going the route of flashing the ecu? I am surprised I can't find anyone who has done this online!