engine swap M20 Swap Questions

[PetrolJunky]

Hello,

 

The M20 harness was connected to the fuse box and I cut it off yesterday so it should be fine. I have 2 greens that come off the c101 connector one is solid and one has a tracer.

 

If you happen to be in AZ for the weekend stop by :-))

 

Matt

[M3M3]

not all c101 connectors are the same.  the pins and wires on either side varied by year and engine in the e30. 

 

if it ran before you cut some thing off, relook at what was cut.

 

if it did not run, pull out the etm and start tracing wires.  at least confirm that the wire colors on each side of the c101 have continuity.  take the connectors apart and follow them.

 

you can spend the time now to make sure everything is right, or you can spend forever chasing electrical gremlins.....maybe it is just me, but i always choose option 1.

[PetrolJunky]

I am not looking at it, but I am %90 sure that they do not match on both sides. I am assuming I should follow the wires on the fuse box side?

[mike472]

I am a bit confused If you have MS3 you are going to have to wire the all the sensors to MS's relay board if that's what came with the car and you won't be using the e30 plug at all. You can't have both the factory ECU and MS ECU. I would check to see exactly what you have as far as the major components. Go to the mega manual on MS's website and do some reading on the system and you'll get a better idea of how their fuel injection system works. If you don't have MS's relay board you will have to create one of your own with a fuel pump relay and main relay along with a terminals strip to wire up all the sensors to the ECU. The MS relay board makes the job easy as it has the relays you need along with fuses and a terminal strip for connecting the sensors on the engine to the MS ECU box. I bought the relay board along with the six foot long 37 wire(thick!) cable to connect it to the ECU in the glove compartment. The MS system does not use the stock airflow metering box so it should not be on your engine with the MS system. It uses a MAP sensor instead. This is better then stock because it eliminates an obstruction in the airflow and cleans up unneeded plumbing which is always good if you have a Turbo system. You are better of with MS and a Turbo. Much more tunable then stock. The stock airflow meter is no good for metering fuel for a turbo. Not like the MS system which senses manifold pressure and adjusts fuel mixture accordingly. With a turbo you need a MAP sensor that will measure up to about 45psi depending on the amount of boost you want to run.

Relay Board

MS ECU

[PetrolJunky]

Mike472,

Thanks for the comment.

I understand that the ms3 is going to have to be rewired. Since it is someone else's build that I am trying to figure out, I feel that it's best to get it wired and get everything running.

Maybe I am going about it wrong, I am over my head on the whole thing :-)

[mike472]

You cannot avoid the real labor of thinking. Read the mega manual starting at the top of the MS3 section where it says "fuel system". Keep reading and scrolling down til you get to the end. Then do it again. And again. You are flying completely blind right now from what I'm hearing in your posts and you will continue groping for a solution until you do this or somehow get extremely lucky and wire it right by accident although I doubt that very much.

Try it. It's not that's hard. They have good pictorials that will help you understand.

[PetrolJunky]

Hello,

 

Here are the MS3 parts that came with the car. It was built by a service manager at BMW.

 

 

Matt

[morfiya]

if this was my car and the ms is not wired in yet i would get it running on the stock ecu wiring in the m20 is really not that bad abought 6 wires and boom should run use the search lots covered on this if not send me  a email ill send u some pics of mine currently running a m20 with 2 small turbos

[PetrolJunky]

morfiya,

 

Thank you, that is what I was planning on doing, I wanted to get it all running and make sure everything was up, then I would deal with the megasquirt.

 

I would absolutly love photos of yours, I am having a hard time with this. I am a programmer so I am good with logic but these wires truely fluster me.

 

Details of the wiring that you had to do would be awesome!

 

Matt

[mike472]

You have the main MS ECU but no relay board.  It doesn't look like it was completed as there are still some things that need to be assembled from what I can see in your picture.  It looks 95% done.  I hope you have the build manual.  Its easy enough to get if you dont.  You would just need the relay board and cable which will cost you a couple of hundred bucks.

 

You can take the stock route for now but I don't think its going to be very easy to modify for use with the turbo.  No adjustability unless you piggyback some sort of enrichment device onto it.  I'm sure people on the forum have done this but in the end, the MS is better as far as adjustability.  Your choice.

[PetrolJunky]

I am sitting here with it.

I have the c101 connector with the wires connected.

I ran a voltage meter in all of the wires on the c101 that I used and none are showing any power. Is that correct?

Also, the car itself does not connect to any power, I have come the the conclusion that it should connect to the battery.

Those may be very stupid comments, sorry, I am just learning here.

[TobyB]

Have you downloaded the ETM yet?

 

Do you have the E30 relay box?  It has 2 to 4 relays in a rather large plastic box, and you need it.

 

All your answers, and a lot more questions that you don't even know about yet, are in it.

 

t

[PetrolJunky]

Hello,

I do not have that relay box, I will try to find one.

I did get it started a minute ago, pretty exciting!

[M3M3]

Ahhhhh.....you said you had the relays on first page of this thread.