Wiring, vacuum line, and cooling diagrams

[pussiwillow]

Alright, I'm prepping for when I finish my motor. I'm building an m50 3.0l stroker and converting to obd2. My motor had the harness cut and halfway disconnected upon receiving. All coolant hoses where cut, and I don't have much of a clue where the vacuum lines will run. I need pictures, diagrams and everything helpful, whether they're pictures of your manifolds off I can focus on your coolant lines and vacuum routing. Vacuum is the big hang up as I'm converting to obd2 while converting back to an obd1 manifold. Diagrams or pictures for obd2 labeled wiring harness, cooling system route and vacuum line routing for obd2 with obd1 manifold. I hope I made sense, I just need to get this all in line and will help tremendously on saving time. Thank you all

[flyfishvt]

That is not a common swap. Have you checked out the Engine Swap forum? You should also read the M50 manifold swap thread. It will allow you to do some reverse engineering.

What condition is the wire harness in? any missing connectors? You'll need an OBDII wire harness for this so you can get the o2 sensor connectors and the SAP connector. YOu'll also need a custom tune which you probably already know. Since you're going OBDII and a custom tune it would be a good time to do EWS delete. Unless you have software to align the DME to your car.

[pussiwillow]

It's not a common swap, it requires the crank shaft positioning sensor from a euro m52, they used a front mounted hall sensor in the same location using the same wheel as the m50. I am doing a sap delete, and am deleting ews. I will be running a stock s52 ecu, I'm doing a 3l stroker with m3 cams. It's been confirmed it will run perfect.

I just need diagrams or pictures of coolant hose routing vacuum routing and a labeled harness, I have not bought a harness yet. They are usually never labeled when people remove them, but hopefully I can find one, is obd1 and obd2 coolant routing the same? I've read the manifold swap thread, it helped greatly but I'm still having trouble, real oem will probably be my best bet, just hoping someone that rebuilt a motor took pictures of where everything hooks up and can post them

[paniolo]

Here is a pic with my OBD2 intake off that shows a lot of the hoses. Red arrows are coolant lines from the block, blue arrows are the returns. White circles attach to the intake, arrows show the vacuum lines. The visible white lines to the front feed the SAP exhaust valve. The two back circles, one goes to 328 exhaust flap and other to FPR. Green arrows are the fuel.



Pic of underside of M52 intake with vacuum hoses and ICV attached. The one way valve after the T goes to the SAP valve around the front of the engine. The other side of the T goes back to the exhaust flap on the 328. The short straight hose connects to a plastic hard line that routes to the FPR.



Hope these help

[pussiwillow]

Thanks a ton man! Very helpful! Anything I can find is great! I appreciate it man

[paniolo]

One thing you may have to deal with is the return pipe that all those blue return hoses identified in that first pic run too. On obd2 that is a physical pipe those hoses attach too and the other end attaches to the back of the t-stat housing and is sealed with an O ring. It is #6 in this realoem.com pic.



The M50 used a hose for the return line instead of a pipe and it attached to a nipple on the back of the t-stat housing. Item #6 on this '95 325is realoem pic.



I don't know if the attachment point to the back of the t-stat housing is part of the block and something that can not be modified? I like the M52 set up cause everything is pretty easy to replace, but going with the M50 hoses should not be an issue either.

One other issue I have wondered about is the throttle body heating hoses. On the M50 there is a t-stat as shown in above diagram (#11), that I assume is a reverse t-stat that closes when hot to keep the incoming air charge as cool as possible. That was deleted in the M52, I assume for cost cutting. I know some people here have eliminated that line on the M52 to keep the throttle body as cool as possible, maybe at the expense of cold weather smoothness. Have you thought about what you want to do with that? I would love to have real time obd2 monitoring to see what the air temp sensor reads with that heating hose attached and with it blocked and try and then figure out the hp impact.

edit: Oh snap! I bet the M52 pipe just used that existing hole where that t-body thermostat mounts on the M50 and they just blocked the hose nipple from the M50. So you could probably use any combination of those setups depending on what parts you have or can find cheap on a part out.

Thanks a ton man! Very helpful! Anything I can find is great! I appreciate it man

You're welcome! Glad I had the pics. At the time I did a detailed diy of replacing all the hoses and vacuum lines under the manifold, I decided to play with a vector graphics program to figure out how to annotate pics with colored arrows. It was a bit time consuming, but I learned something and you would not believe how often I have used that pic to show people where things route under the manifold. Glad to hear it helps people.

[pussiwillow]

Awesome that helps tremendously for sure! Thank you