SWAP Thread: '91 325i Sedan - S50b30us

[hwy84]

FPR vs. FPR

Ha, yes. By FPR I meant Fuel Pump Relay, even though I typically mean Fuel Pressure Regulator. Apparently now FPR = Feeling Pretty Retarded.

In any case, thanks for confirming. I'm pretty certain I jumped 30 and 87 (based on the numbers on the relay pins), and got nuthin'. I'll move on to fuses and then directly to the pump next.

Thanks - and keep the suggestions flowing, I am all ears!

Oh - and thanks for the 4-door props... but don't congratulate me yet! I'll feel worthy of congratulating when the thing moves under its own power. :curse:

[hwy84]

Holy crap!

IT RUNS! Sweet sky above, it RUUUUUNNNSS!!!!!

Turns out the stomp test code had nothing to do with anything and was a big red herring. I pulled the fuel pump relay, jumped it, and listened to the pump (with the back seat off) and I could hear it spin. Knew then that the pump was good. Quintuple checked my wiring, and I was confident it was correct.

What's left to check when all the electronics call for fuel, and you get no fuel? That's right. The fuel lines.

Yup. I had reversed 'em.

Put them the right way, and the "M Crap" started right up, stumbled for about 20 seconds, and then just settled into a nice smooth idle. (A very angry idle, since I only have the center section installed right now, and no muffler. Actually sounds awesome.)

So yeah. That's it. You gotta love when your car keeps you humble. It's like I was getting too cocky, and my car said,

Sure you can study the ETMs for 3 different cars, and make a wiring harness that works, and do all the other thinking crap that goes into this swap... but F you. You'll screw SOMETHING up.

And the car was right.

But I just don't care. I am so excited I could just about die. In fact, I may die, since I am currently covered in gasoline... Pulling the reversed lines off the rail sent a gallon-sized money shot of high pressure gas all over me.

Off to the shower.

Thanks for the help r3v!

[Danny]

Good to hear of another s50 4door in the bay!

Congrats on getting her running!

[hwy84]

Good to hear of another s50 4door in the bay!

Congrats on getting her running!

Thanks, man! Now... Smogging. Hopefully this will go smoothly.

Gotta love California!

[cmybimmer]

Congrats!! And i'd hate to be working on a car with this chilli weather andd such short days. I was working on my swap during the summer and the 15 hours of sunlight in a day seemed to fly by :rofl:. Props :up:

[hwy84]

24 valve/4 door mafia?

Thanks, and you're right - I owe this whole swap to the power of a cheap no-name headlamp, and the heat of burning frustration/rage that kept me warm under the car in 30 degree temps when I was swearing at bolts and wires and reversed fuel lines. ;)

My kingdom for a garage...

Looks like the Norcal 24v/4-door Mafia is all assembling in this thread! Sedans FTW!

[cmybimmer]

I can imagine the frustration.. But its all in the past now. Time to go for lots and lots of joyrides!

I want s50/s52 power now :(

[328ijunkie]

Glad you got it figured out!

Btw: Diagnostic 16 17 <- not needed. And wont really do anything.

[hwy84]

Glad you got it figured out!

Btw: Diagnostic 16 17 <- not needed. And wont really do anything.

Damn. How will my engine know if I have the flu? I was so hoping for rapid diagnosis. ;)

Seriously though, that isn't continuity from the Diagnostic connector to the ECU? I admit, I didn't delve deeply into it in the ETM, since I figured it wasn't critical to actually running the car...

<EDIT>

I think I answered my own question. Looks like X20 Pin 17 feeds diagnostic info to the OBC... which my E3 ain't got. Yes?

[328ijunkie]

Pin 16 and 17 on the x20 are purely diagnostic for the e36. It's so you can plug into the diag port and talk to the abs, body control module, srs, etc.

[hwy84]

Brakes Drag - Pedal returns slowly

Nope, no binding or other issues with a relocated stock booster. feels just like it did before the swap.

Well, I have taken the car out for a couple shakedown runs, and my brake pedal is very slow to return.

With the car OFF, the pedal returns, but it is slow. Maybe takes literally an extra second to return the last inch of travel all the way to the top after I remove my foot.

With the car ON, the vacuum in the booster keeps the pedal from returning for much much longer, and the brakes drag.

My booster rod is attached to the stock mounting tab that is on the SIDE of the pedal assembly. This means the rod is angled. Is it possible that the angle in the linkage means the rod is dragging on something inside the booster, and that the return spring isn't strong enough to overcome that drag anymore?

How have other folks solved this booster issue? I imagine I could drill the pedal arm and put the clevis on the pedal arm itself, but that seems like it will weaken the pedal arm in a way I am not super excited about...

Any other thoughts on the slowness? I have bled all the air out of the system. I ran literally 2 liters of fluid through the system, and it is bleeding totally clean and free of bubbles...

[328ijunkie]

Its binding. Move the booster over more.

[hwy84]

Its binding. Move the booster over more.

Bummer.

I have very little clearance between the booster and the intake manifold as it is (less than 10mm) - I can imagine that the engine could move enough on the mounts to contact the booster if I move it any closer, especially as the mounts wear over time. How close are people getting?

I only moved the booster 12mm (just under half an inch) - and others seem to have done this no problem... was there something else I should have done to make it work without binding?

I am curious to know how other "stock booster" folks dealt with the linkage...

Of course, I drilled new holes in the FW instead of slotting it, thinking it was going to result in more secure mounting. Now it just means less flexibility for moving the booster.

[328ijunkie]

No i mean move it farther away from the manifold.

[328ijunkie]

My car:

Booster shaft is straight as an arrow.


Ninja edit:
This is the reason i never use stock boosters on customer cars... GHETTO!