E30 m3 c101

[aaronmjr]

So the E30 M3 kept some of the early E30 stuff like the radiator setup, do you know if the C101 body side is wired the same throughout all years? Long story short I need a ready built engine harness for my S52 swap, and someone has one locally that is pinned for an 89' 325i C101. My M3 is a 1990.

[bmwmech1]

Get the ETM for both cars and compare. They are different from year to year, so you need to be sure the one for sale is compatible with your harness. BTW, most everything on the harness is the same whether it's an M3 or not, excluding a few small differences... There are a bunch of us doing V8 swaps and everyone's adapter harness wiring has been slightly different, year to year...

Garey

[aaronmjr]

I have both ETM's, but I don't see a section where it lists what-pin-is-what for the C101 connector. I found a spot where it lists those things for the diagnostic connector but that's it. Is there something simple I'm missing?

[aaronmjr]

I'm guessing this is what I need to do. Ugh.

Find the manual for your car or engine, whatever side you are doing pinouts for.

Open the manual, and skip to the section that starts talking about power distribution and various under hood parts.

This is what it will look like:





You want to look for any instance of either c101 or x20, such as what is circled. C101 is the e30 engine connector, x20 is the e36/e34 connector. So if you are looking at an e30 manual, just look for c101. When you look at the e36/e34 manual, look for x20.

The c101 connector is the big round connector on your firewall. It has 20 or so pins on it (it’s a square connector with less pins if you have an 84-85 model). Each pin will be drawn out in this manual. Here, in the example, we are looking at pin 10 (see the 10 next to where it says c101).

The curved lines show which way the signal is coming through the connector. In this example, you see it’s coming FROM the oil level sensor, TO the engine oil fault indicator (the oil level light in your car).

The VI/GN and BU/WT are the colors of the wires. The wire between the sensor and the connector is blue with a white stripe, the wire between the connector and the warning light is Violet with a green stripe.

The .5 next to the color is the wire size. Apparently this is in millimeters squared. .5 will be a little wire, .75 medium, 1 is big. (I think).

You now know what color the wire is on the engine side, what color t is on the body side, what pin it is in the connector, and what its function is.

The schematics are generally laid out as power (+12 volts) from the top of the pages, to ground at the bottom of the pages. Further details of what various symbols mean can be found in the beginning pages

[Jason89i]

only two or three are different. nothing major. cross reference with etm.