m42->m20 swap

[Shift_Now]

Well I just completed the m42 to m20 engine swap. I hooked up the connector for the wiring harness to the fuse box, aswell as the wires at the junction block. I have spark, as well as fuel, but I still cannot get the thing to fire/run. As far as I can tell, tehre are no vacuumm leaks(so I ruled that out), all the connectors that are part of the wiring harness seem to be connected. Are there any additional wires I must run? what is the deal? thanks

[Dyno4mance]

I am doing the same but have not got that far yet....please keep me posted as to what was the issue as I am sure I will hit the same problems...
there seems to be a few posts about this swap over on e30tech.com

[G60 CAB]

Just helped another R3Ver with this problem. Not 100% sure on if this works for everyone but this is how I got my system to work.

Would probably be a good idea to sticky this just in case.

Obviously soldering would be more ideal but I went with the butt connector route since I wasn't sure about everything.

First wire goes from fuse #5 to the ECU harness. Just tap one of the two wires coming off the fused side of the circuit and run the wire through the firewall by the harness grommet.



Now this is a little complicated. That wire from #5 fuse runs into the solid red wire from the ECU AND the solid green wire ALSO runs back into the solid red wire. So two wires into one. Most likely, that solid green wire will be running to the white connector, I pulled it out and just looped it with the wire from #5.



Now for the tach to work, the two wires that run to that white connector will be ran to the cluser on the BLUE CLUSTER connector (black and white wire on the cluster connector). The blue/black wire will be ran to the BLACK wire on the cluster connector and the white wire runs to the white cluster connector.

Also, make sure you have an M20 coding plug for your cluster or your tach will be off.



And this might be required on your car too, I found this out the hard way. During this swap, you MIGHT have lost power to your power windows and blower motor, in which case you will need to do the following:

Relay K5 and K7 are both unloader relays which act opposite as a normal relay, so you may have lost a ground during the harness swap that you will need to add for your windows and blower motor to work.

The green/black wire that runs under the circuit board for K5 and K7 (pigtailed with two wires running out of it) will need to be grounded to somewhere on the chassis, which will complete the circuit and bring the power back to your windows and HVAC system. I just tapped the wire in the middle where it goes from K5 to K7.

[Shift_Now]

what does the fuse #5 control? It turned out that when I put in the 19lbs injectors the ECU hadn't adjusted to them, so I swapped in the old injectors, and it ran fine. I didn't have to hook up any wires, nor run any additional wires, nor did I have any unused connectors( But I no longer have ABS brakes?)

[G60 CAB]

Hmmm, no idea, but thats what it took to get mine running. Weird.

I don't have ABS either, must have lost a connection during the C101 swap.

[Funkmasta]

Just helped another R3Ver with this problem. Not 100% sure on if this works for everyone but this is how I got my system to work.

Would probably be a good idea to sticky this just in case.

Obviously soldering would be more ideal but I went with the butt connector route since I wasn't sure about everything.

First wire goes from fuse #5 to the ECU harness. Just tap one of the two wires coming off the fused side of the circuit and run the wire through the firewall by the harness grommet.



Now this is a little complicated. That wire from #5 fuse runs into the solid red wire from the ECU AND the solid green wire ALSO runs back into the solid red wire. So two wires into one. Most likely, that solid green wire will be running to the white connector, I pulled it out and just looped it with the wire from #5.



Now for the tach to work, the two wires that run to that white connector will be ran to the cluser on the BLUE CLUSTER connector (black and white wire on the cluster connector). The blue/black wire will be ran to the BLACK wire on the cluster connector and the white wire runs to the white cluster connector.

Also, make sure you have an M20 coding plug for your cluster or your tach will be off.



And this might be required on your car too, I found this out the hard way. During this swap, you MIGHT have lost power to your power windows and blower motor, in which case you will need to do the following:

Relay K5 and K7 are both unloader relays which act opposite as a normal relay, so you may have lost a ground during the harness swap that you will need to add for your windows and blower motor to work.

The green/black wire that runs under the circuit board for K5 and K7 (pigtailed with two wires running out of it) will need to be grounded to somewhere on the chassis, which will complete the circuit and bring the power back to your windows and HVAC system. I just tapped the wire in the middle where it goes from K5 to K7.

Can you re-post the pictures?