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-   -   How to re-wire the main engine wiring harness?? (

JinxyJ08 10-10-2012 10:20 PM

How to re-wire the main engine wiring harness??
Well i haven't been on in a while as I have been contemplating selling my 540. I do really like it so i may fix it if i can figure out how to rewire part of the wiring harness from the ECM to the engine. I would also need to get a reprogrammed ECM which i beleive I have found as well. I have already replaced a good bit of parts on the car and the whole secondary air system minus the pump (all valves, hoses, "egr" gaskets intake rear manifold gasket, etc.)

About 5 months ago my car had a ton of issues (Here is the old thread title with allll of the information - '02 540i keeps dying? **UPDATED WITH CODES**) mainly with the car losing power at normal speeds and dying. Wouldnt stay running, sounded weird as hell, and overall just sucking at life.

Well i finally broke down and took it to Auto Assets which is a europeon only repair facility who has deemed the issue is a contstant 12 volts going to the EGR control valve. So the issue is the car has a constant vacuum leak with this valve open. They have said the car has a burnt ECM and the wires are burnt as well. I haven't pulled it all apart to inspect myself which i am going to do this weekend, but taking their word, i need to rewire the main engine wiring harness wires. Can someone tell me how to do this? My other option is to purchase a full wiiring harness from BMW since i cant find it anywhere else and spend tons of time replacing that thing which i REALLY dont want to do.

So if someone can help me figure out how to rewire this harness i would be greatful as can be as im sure it will need re-pinned at the connector.

john@eac 10-11-2012 07:45 AM

Lets just say I have never seen a wiring harness to the computer melt down. The best thing to do would be to replace the harness if it is that bad. If you do attempt to repair it make sure that you solder all wires ( no butt connectors unless weather proof with solder) and heat shrink them. Until then I would unplug the EGR vale so it stays closed. The weather proof butt connectors have solder in them. You slide them over the wires hook the wires together, slide the connector over the wires, heat to melt solder and they heat shrink right around the repair. I usually get them at the local NAPA store but you might have to educate them on what you want .

JinxyJ08 10-11-2012 10:40 PM

I'm going to look at it again soon. If it is burnt at the harness what do I need and how do I to re-wire and possibly re-pin it? Does anyone know where to get the correct harness and it not cost me a ton?

josemedeiros007 10-12-2012 06:12 PM

If you need a good used replacement harness, I would try Bavarian Auto Recyling
I am told that a Bently Shop manual has the best wiring schematic for a BMW, but I don't have one yet.

There is an online wiring schematic you can use, but I and another on this forum found an error with the sensor wiring color for the connector for a Charcoal Filter schematic also called a Evap Purge Control Valve.

My sensor issue thread:

CN90's thread is very informative:

Jose F. Medeiros
1998 E39 528i 265,000 miles
San Jose, California
Thomas A. Edison: 'I have not failed. I've just found 10000 ways that won't work."

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