M50 Harness Question

[Blitzer418]

Hi all,
I just purchased a BMW M50 engine, but I don't actually own an E30. I'm actually looking to swap this engine into my 1972 Triumph TR6. I know this is an E30 forum, but I figured you guys would have the most knowledge for M50 engines.
Obviously I can't connect the M50 harness plug to the car, but can I connect the individual pins to the corresponding function (ie starter to button, ignition to key) or is it way more complicated than that?
Any information would be fantastic. Thanks guys!

[Nick's e30]

Hi all,
I just purchased a BMW M50 engine, but I don't actually own an E30. I'm actually looking to swap this engine into my 1972 Triumph TR6. I know this is an E30 forum, but I figured you guys would have the most knowledge for M50 engines.
Obviously I can't connect the M50 harness plug to the car, but can I connect the individual pins to the corresponding function (ie starter to button, ignition to key) or is it way more complicated than that?
Any information would be fantastic. Thanks guys!

You're going to need to watch for resistance changes and electronics differences. It was so complicated to try to get my stock stuff to work with my e30 5.0 swap that I ditched my stock instrument cluster entirely. My tach would bounce around unpredictably and my coolant temp gauge was similar. I'm also not an electronics guy and I didn't know exactly what to change to get things to work 100%.

[Blitzer418]

You're going to need to watch for resistance changes and electronics differences. It was so complicated to try to get my stock stuff to work with my e30 5.0 swap that I ditched my stock instrument cluster entirely. My tach would bounce around unpredictably and my coolant temp gauge was similar. I'm also not an electronics guy and I didn't know exactly what to change to get things to work 100%.

Hey Nick, thanks for the reply. Do you mind me asking what gauge cluster you used instead (or maybe you meant you got rid of it all together ), I was planning on going to the scrap yard and finding a 325 with the gauge cluster still in it. If not then I'll resort to online shopping.

[Mwishlist]

That sounds like fun, how much does a TR6 weigh?

If you don't have the electronics troubleshooting manual for the engine you can find it here:

http://wedophones.com/BMWManualsLead.htm

You may want to look at older BMW swaps as well. I think 2002 guys use a tach signal amplifier to make the low signal from the M50 ECU work with the old style tachs that normally take their signals from the coils.

[M3PO]

The M50 is pretty "standalone". When we swap these engines into E30's, there are only a few wires that need to "interface" with the vehicle/dash harness. Other than that, it's essentially providing power and ground.

For your Triumph, your main concern will probably be fuel pump, starter, ignition, tach, CEL, and alternator charging wires. Also, the DME/ECU needs a VSS (vehicle speed signal) that comes FROM the cluster/speedo or you'll have a reduced redline. That's easy to tune out though. There are plenty of tuners on here that can set you up with a VSS delete chip with a nice tune on it for a little more power.

You'll also need to get the correct coolant temp sender (probably the triumph sender) mounted in the head and get that connected up to the correct wire on your cluster. That's easy though. There are two senders on the M50, one for the DME and one for the cluster. Just replace the cluster one with the Triumph one and wire it up through the M50 harness.

The only issue in terms of using your triumph cluster will be the tach. The tach signal output from the BMW DME probably won't work with the Triumph tach.

edit: These engines have a fuel return. Not sure if your Triumph does but that might be another issue you'll have to sort out.

[Blitzer418]

That sounds like fun, how much does a TR6 weigh?

If you don't have the electronics troubleshooting manual for the engine you can find it here:

http://wedophones.com/BMWManualsLead.htm

You may want to look at older BMW swaps as well. I think 2002 guys use a tach signal amplifier to make the low signal from the M50 ECU work with the old style tachs that normally take their signals from the coils.

Yes, it should be a lot of fun! A stock TR6 weighs around 2300lbs, and the seller told me it'll be about 100 lbs lighter with the M50 engine.

As for the tach and speedo, the original gauges in the Triumph are actually good ol mechanical cables my original plan was to get a 325 gauge cluster and transplant the motors into my original gauges to replace the mechanical cables. Not completely sure how well that will turn out..

For your Triumph, your main concern will probably be fuel pump, starter, ignition, tach, CEL, and alternator charging wires. Also, the DME/ECU needs a VSS (vehicle speed signal) that comes FROM the cluster/speedo or you'll have a reduced redline. That's easy to tune out though. There are plenty of tuners on here that can set you up with a VSS delete chip with a nice tune on it for a little more power.

I'm hoping to walk around most of the problems buy somehow transplanting a 325 gauge cluster in.
You're also correct about the fuel return line, the Triumph didn't have one before. The tank is already out of the car, and I'll get someone to refurbish and weld a plug on it for the return.

As for the ignition, I found this simple diagram: http://circuitswiring.com/1993-bmw-m...iring-diagram/

Is this it possible for me to find the cable that goes to the ignition coil and hard wire it into my current switch?

[Blitzer418]

Heres a picture with a S50 in a TR6:

[f4tj0n]

You could also run nice aftermarket gauges?

[nando]

I think you will want to run an aftermarket tach. the E30 tach is probably more complicated than you'd expect - it's controlled by the SI board, so you can't just swap the tach itself into another cluster and have it work.

as far as running the M50 itself, it should be very doable. There's really not too many wires that you will need to have.

If you really want help though what you need to do is make a list of the wires that you want to hook up from your Triumph - what they do, what sort of signal it is, voltages, etc. Then we can tell you which wires correspond to the M50 harness and what will need to be modified or replaced.

[M3PO]

As for the ignition, I found this simple diagram: http://circuitswiring.com/1993-bmw-m...iring-diagram/

Is this it possible for me to find the cable that goes to the ignition coil and hard wire it into my current switch?

That diagram appears to be for an M20. The M50 is a coil-on-plug configuration. It's simple, but not THAT simple.

Someone above posted the wiring diagrams (called ETMs around here), that's where you should be looking. Specifically, the C101 connector for your year of M50 is where you will need to interface with your Triumph so learn it and get to love it lol!

As mentioned, you probably won't be able to transplant JUST the tach into your cluster, you will likely have to transplant the whole cluster. If you dig deep enough into the diagrams, you might be able to make it work but the cluster is pretty "integrated". I would look into a module to run your Triumph tach. Dakota Digital may make something that will convert the the BMW signal and spin your mechanical tach. Having an all original Triumph cluster would awesome!

edit: something like this http://www.abbott-tach.com/cablex.htm

[M3PO]

There are also companies out there that will convert your tach to electronic so you can have the original look and use the BMW signal.

[Blitzer418]

I think you will want to run an aftermarket tach. the E30 tach is probably more complicated than you'd expect - it's controlled by the SI board, so you can't just swap the tach itself into another cluster and have it work.

as far as running the M50 itself, it should be very doable. There's really not too many wires that you will need to have.

If you really want help though what you need to do is make a list of the wires that you want to hook up from your Triumph - what they do, what sort of signal it is, voltages, etc. Then we can tell you which wires correspond to the M50 harness and what will need to be modified or replaced.

I've attached a picture of the Triumphs incredibly simple wiring diagram and I've circled the ignition wire along with the starter wire. Both have the voltage of the battery coming through when the switch is engaged and is connected to a ground. As far as I know, those are the only two components I'll be using from the stock TR6 wiring.

Edit: It may also be worth mentioning that in those two circuits there is no fuse (although I doubt there should be one, does an E30 have a fuse for the starter and ignition?)

That diagram appears to be for an M20. The M50 is a coil-on-plug configuration. It's simple, but not THAT simple.

Someone above posted the wiring diagrams (called ETMs around here), that's where you should be looking. Specifically, the C101 connector for your year of M50 is where you will need to interface with your Triumph so learn it and get to love it lol!

As mentioned, you probably won't be able to transplant JUST the tach into your cluster, you will likely have to transplant the whole cluster. If you dig deep enough into the diagrams, you might be able to make it work but the cluster is pretty "integrated". I would look into a module to run your Triumph tach. Dakota Digital may make something that will convert the the BMW signal and spin your mechanical tach. Having an all original Triumph cluster would awesome!

edit: something like this http://www.abbott-tach.com/cablex.htm

I didn't even know there is a conversion from electrical to cable, thats really cool! I may have to do some more research and see if I can find the right one for the right price.. It would definitely make my life a lot easier.

[nando]

the E30 does have fuses but they are not in the wiring harness, they are built into the fuse box. there's a fusible link from the battery to the DME that will protect it if there's an overcurrent or if somebody hooks the battery up backwards.

I don't think there is a fuse for the starter but there's definitely one on the ignition switch. I think it's 30 or 50 amps. There will also be fuses for the fuel pump and maybe a couple other things. the ETM is pretty detailed though and will show it all.