M52 Swap Fuel hook up questions

[Bmrlvr4lfe]

Hello E30 fanatics!
Im in the process of rebuilding a 1987 325is, here are some details….
M52 swap
M50 intake
Kassel M52 MS41.1 ECU reprogram and tune.
Ultimate Swap program (M50 intake, sap, ews removal)
getrag 260
Kassel plug and play wire harness (existing off m52- they did all the work on it and sent it back me)

We dropped the engine and transmission in, I am currently hooking the wire harness up and have come to some questions that I am needing the help from this group on…

1. I have both a m50 and early model m52 fuel rail. What’s the difference? And I’d there any benefit to using one or the other?

2. I’m having trouble wrapping my mind around the fuel actuator and how that gets hooked up properly. I have the one that was attached to the early model e39 fuel rail but I’m not sure where the vacuum lines go.

3. I read a lot about charcoal canisters and whether to use them or not. I have the e30’s should I hook it up or not, if so what vacuum lines get attached?

4. The reprogram of the ECU took out the SAP, what should I do with the sender on the intake side of the engine? It has a electrical connector and vacuum lines.

Thank you in advance, this board has got me this far and I appreciate all the contributions everyone has made. This is my first e30 but not my first BMW. (too many to count…🤪 )

Ben
Central VA
currently
F30
F15
E30

[mjweimer]

Sounds like a fun project. I have put a few comments below.


1. I have both a m50 and early model m52 fuel rail. What’s the difference? And I’d there any benefit to using one or the other?

M50 fuel rail has the supply hose at the front of the rail and the return hose at the back (firewall) side. Early E39 M52 rail has the supply and return both at the back side. Both will fit, E39 is cleaner in my opinion since both lines can route just along the firewall from the hard lines at the frame rail.


2. I’m having trouble wrapping my mind around the fuel actuator and how that gets hooked up properly. I have the one that was attached to the early model e39 fuel rail but I’m not sure where the vacuum lines go.

Is your M52 rail really an early E39 rail or are you talking about the OBD2 3/2/running lossless set-up that has a remote fuel pressure regulator and a fuel pressure feedback connection?
The pressure regulator on an early E39 rail should only have one vacuum line connection that would be connected via a 3.5mm hose to a port of the same size on the bottom of the intake manifold. The M50 rail should have the same exact pressure regulator in a slightly different location.


3. I read a lot about charcoal canisters and whether to use them or not. I have the e30’s should I hook it up or not, if so what vacuum lines get attached?

You need to vent the fuel tank somehow, so you can either delete the charcoal canister and vent the tank to atmosphere or connect the M52 purge solenoid to the E30 charcoal can. Just a couple of feet of fuel hose will get the job done and you won't need to worry about fuel smell or coming up with a good method to vent the tank. Just don't leave the tank vent line disconnected in the engine bay on the frame rail if deleting the canister, follow it back to the tank and figure out how you want to vent it at the back of the car.


4. The reprogram of the ECU took out the SAP, what should I do with the sender on the intake side of the engine? It has a electrical connector and vacuum lines.

I removed all of the vacuum lines and capped the port, I also modified the harness by removing the connector and associated wires....I believe these come out of the fuel rail harness but it's been a bit...if I'm remembering correctly, you can pop the cover and figure out where to snip the wires, cover with heat shrink, etc.

[Bmrlvr4lfe]

MJWEIMER: Thank you so much for the information, very helpful!! I will look at all of this when I get home, really thank you for taking the time to help me! Ben