When the eta engine in our LeMons 87 325e parted ways with coolant and cooked itself, I bought another 86 325e former LeMons car which already had an M50 swap and was already running and driving. It had rolled and the body wouldn't pass tech so they sold it cheap.
Anyway, I'm getting started with the work to install the M50 in my car and am tackling the wiring. When I first looked at the harness I noticed it was kinda hacked up, lots of stuff cut and spliced, and the C101 connector was cut off in favor of some Radio Shack computer connector. So I decided to buy a replacement harness so I'd start from scratch and be able to cut the original C101 off the E30 harness and splice it to the new M50 harness so it'll plug in with the OE connector. Unfortunately I ended up getting an automatic harness but I can make it work. I was using this chart as reference
I later realized what I thought were lots of hacked up connectors are actually factory splices that are normally hidden inside the plastic firewall box wire holder thing, heh. So it's not as bad as I thought.
I first compared to the ETM and the wires seemed to match the chart despite a couple of color differences. As I looked at them today, I realized the old M50 harness that came from the donor car only had 7 wires connected to C101 replacement connector. I traced them and compared them to the uncut M50 harness, and they are (position # from original E30 harness):
1. Alternator - blue
4. Coolant temp - brown/white
5. Oil pressure - brown/green
7. Ignition - green
9. Tach - black
13. Fuel pump relay - green/violet
18. Ignition - black/yellow
The car ran and drove fine (I drove it), so obviously it worked, but would this combo of wires hooked up alone cause any problems? I noticed the plugs were pretty carboned up. The car didn't have an oxygen sensor at all IIRC.
Ideally I'd like to simplify the wiring as much as possible, so using the 7 wire harness is appealing. Bear in mind this is in a gutted race car with no interior, no check control panel, only the stock instrument cluster (for the fuel gauge and tach, but I just got an aftermarket tach since our 5K eta tach won't cut it anymore). I'll be running aftermarket oil pressure and water temp gauges with pressure warning lights, so all I really need is the gas gauge on the original cluster.
Opinions?
Anyway, I'm getting started with the work to install the M50 in my car and am tackling the wiring. When I first looked at the harness I noticed it was kinda hacked up, lots of stuff cut and spliced, and the C101 connector was cut off in favor of some Radio Shack computer connector. So I decided to buy a replacement harness so I'd start from scratch and be able to cut the original C101 off the E30 harness and splice it to the new M50 harness so it'll plug in with the OE connector. Unfortunately I ended up getting an automatic harness but I can make it work. I was using this chart as reference
I later realized what I thought were lots of hacked up connectors are actually factory splices that are normally hidden inside the plastic firewall box wire holder thing, heh. So it's not as bad as I thought.
I first compared to the ETM and the wires seemed to match the chart despite a couple of color differences. As I looked at them today, I realized the old M50 harness that came from the donor car only had 7 wires connected to C101 replacement connector. I traced them and compared them to the uncut M50 harness, and they are (position # from original E30 harness):
1. Alternator - blue
4. Coolant temp - brown/white
5. Oil pressure - brown/green
7. Ignition - green
9. Tach - black
13. Fuel pump relay - green/violet
18. Ignition - black/yellow
The car ran and drove fine (I drove it), so obviously it worked, but would this combo of wires hooked up alone cause any problems? I noticed the plugs were pretty carboned up. The car didn't have an oxygen sensor at all IIRC.
Ideally I'd like to simplify the wiring as much as possible, so using the 7 wire harness is appealing. Bear in mind this is in a gutted race car with no interior, no check control panel, only the stock instrument cluster (for the fuel gauge and tach, but I just got an aftermarket tach since our 5K eta tach won't cut it anymore). I'll be running aftermarket oil pressure and water temp gauges with pressure warning lights, so all I really need is the gas gauge on the original cluster.
Opinions?
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