Need help with my s52 swap. Desperate. About to give up and sell everything

[EliE30]

So I bought a roller 1985 325E and a parts car 1998 m3 convertible with a s52. Watched a ton of YouTube videos and figured I could do everything myself. Car has been in my garage for 9 months already… I’m about to give up on it. I need someone to walk me through all the next steps I need to finish it. So I attached the e30 Getrag 260 trans to the s52 and dropped it into the e30. Did the wiring harness myself (see attached pic). I’m just so confused about all the vacuum lines. I did the m50 manifold swap. I had to install cheap eBay fuel pressure regulator. Car cranks and tries to start but doesn’t run. I can get it to turn over by spraying starter fluid into intake. But it runs for 1-2 seconds and dies. What could be my issue? Idc about AC or anything unnecessary, I just want to be able to drive the car… please help 😭 what would be my next step?

I’ve followed the
“DIY: In depth M52/S52 OBD2 swap”
forum that is posted on here and have done most of everything listed. I just want to make sure the engine runs fine before I finish it completely. What I have left to do is to install radiator and cooling system, connect brakes and bleed system, bleed clutch system, power steering, air intake, Ive got a e34 m50 throttle cable but need help fitting it, because it doesn’t seem right.. and then after all that I will need to fab up a whole exhaust with my eBay headers.

[jbontke]

Has the ECU has the EWS removed?

[EliE30]

Yes, here is my tune that I got

[EliE30]

Also I’m getting CEL code P0340 which Google shows camshaft position sensor. Any help with that would be much appreciated.

[jsta1109]

If you're getting a camshaft position sensor error it is quite likely to be a cause of some of if not all of the issues you're seeing. It is a very common to find damaged insulation on the camshaft sensor, have a look under the connector boot and see if that is the case for you. If you do need to replace it, buy a Genuine/VDO branded sensor. Aftermarket sensors will NOT work.



You mentioned a cheap fuel pressure regulator, I would get rid of that and either purchase a quality unit from a reputable brand or find a stock fuel rail with integrated FPR. The stock ECU will expect 3.5bar/51psi base fuel pressure and with a vacuum source it should idle at around 40psi-45psi.

If you wish to completely rule out vacuum leaks and confirm the engine runs okay, disconnect the MAF and try running the engine. This will revert to a base map and it shouldn't care about vacuum leaks (if any).

If none of the above helps, perhaps EWS is an issue? The DME would usually report a code for this on crank and I was under the belief it cut power to the coils/ignition, so even with starter fluid it shouldn't run. It may pay to have a stock tune with EWS delete just to rule out any potential issues with the 'tuned' DME.

[eternal24k]

double check you have your fuel lines are correctly hooked up, it's easy to reverse them, and I would just get a bosch FPR.

When I had EWS, i was not getting any spark, which it sounds like you are getting.

[hoveringuy]

double check you have your fuel lines are correctly hooked up, it's easy to reverse them, and I would just get a bosch FPR.

When I had EWS, i was not getting any spark, which it sounds like you are getting.

Looks like you have the correct fuel rail. Fuel goes in the front and flow to the back, where the regulator bleeds anything over 50 +/- psi. There's a Schroeder valve to test fuel pressure, testers are cheap.
Once you've eliminated fuel pressure you can focus on electrical things.

[Northern]

Are you sure the fuel lines are the correct way around?
Fuel pressure regulator might be bunk, M50 fuel rail will fit directly with the M50 mani.
Fuel pump working? (Prime with key, *and* actually building pressure)
Might need an OBD2 Throttle cable. This isn't mentioned enough but the E34 M50 cable fits the M50 TB.

Cam sensor as mentioned above, but the engine will start without it so I'd worry about getting it running first

[EliE30]

eternal24k yes I triple checked the fuel lines. Can you please send me a part number for that Bosch filter? And help explain where exactly it goes. Thanks!

[travis816]

It’s located Under neath the car, driver side maybe a foot off the rear wheel, near the frame rail.