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    ODB2 S52 Starting Problem

    Ok, this is driving me up a wall.

    Backround
    So i finished the swap, odb2 all oem except for the fuel tank sensor.
    The car ran great, idled perfectly, no issues whatsoever.
    Then it began to have trouble starting, starting and idling fine after two or three cranks.
    Lately it was taking me longer and longer to start, until it left me stranded after trying to start it for about an hour.

    Resolution
    The battery is a fresh bmw battery, the starter spins the motor great.
    I checked compression on the motor, 200,200,205,195,192,190, so thats not bad.
    I replaced the loud, but working, 318is fuel pump, with an e36 m3 fuel pump, that had much more noticeable spinning torque when i bench tested them both.
    I made sure the ews system gets power at all times and when the ignition is switched, also made sure to position the transponder chip properly inside the anntenae ring( which prevented me from initially getting the motor running after the swap).
    Spraying starting fluid is weird because it might stumble for a second or two, but then it won't ignite during later sprays.
    I tried to check for spark, but apparantly the coil needs to be grounded along with the plug itself, so i'll recheck for spark.
    I replaced the crank position sensor with a cheap 40$ duralast, noticed the old sensor had a hairline fracture and was leaking oil. Still nothing:(
    The pikes peak code scanner gives me a few codes for oxygen sensor related issues, but nothing that relates to a no starting condition. No camshaft sensor code or crankshaft sensor code for that matter.

    Im so overwhelmed that i can't figure out whats wrong.
    The symptoms sound like it could be anything from a bad ecu, ews system being missaligned somehow, ...
    I don't think its a bad ecu, because im able to read codes from it.
    I really should get some fuel pressure gauge to see if its near the required 50psi from the schrader valve on the fuel rail.
    Besides all that, i really could use some advice.
    Should i order oem cam and crank sensors to be sure, Should i just have a known good ecu flashed for ews delete?

    #2
    Then it began to have trouble starting, starting and idling fine after two or three cranks.
    Lately it was taking me longer and longer to start, until it left me stranded after trying to start it for about an hour.
    With good scan tool, that can read BMW factory codes, like INPA or Snap On, you can read both the DME and EWS module codes, if there is a problem with EWS it will have a code for it. Also while you are cranking you can watch the data from the scanner and see if you get any RPM there. You got to have good diagnostic tools

    Comment


      #3
      I got it started, put the old crank sensor on and it fired right up!
      In the troubleshooting process i noticed one of the coil boots had a weak spring inside, so cleaned the plugs while i was at it.

      Comment


        #4
        Ok, so since the crankshaft sensor had a crack and worked whenever it wanted to, I replaced it with an oem sensor, and it didn't seem to make a difference.
        It starts when it wants to. Once it's started, I take it on a spirited drive and it performs excellent. Pikes peak scanner still shows a code for the crankshaft sensor and ews signal, the other codes are o2 sensor codes.
        How else can I scan the ecu, since it only has the round connector when installed in an e30!
        HELP, I CAN'T DRIVE THIS BEAST EVERYDAY.

        Comment


          #5
          You can wire up an OBDII port that you can scan OBD codes with. I've done this with my m52 and have hooked up a bluetooth OBDII scanner to my phone via the Torque Android app.

          The wiring is pretty easy. There is actually only one data wire. You can get it from pin 88 on the ECU connector. From there it runs to pin 17 at the BMW round diagnostic connector, then through the cap to pin 2 where it runs into the cabin through the X20 connector.

          The OBD2 port pinout is standard, you can find that info anywhere. For the e36 info, check out page ELE-90 of the E36 bentley.

          You'll probably have to buy an OBDII extension cable to get the correct connector so you can plug in your code reader.
          M/S52 Wiring Diagrams
          Z3M S52 to late model 325i wiring diagram
          M52 to 318is wiring diagram

          Comment


            #6
            There is also an adapter for the round diagnostic plug that will allow you to plug in an OBD-II scanner. I use one with a bluetooth OBD-II adapter and Torque.

            Link

            (For when the ebay link ultimately dies, just Google "20 pin to 16 pin BMW adapter" or "BMW to OBD" adapter)

            '91 318is - OBD-II S52 swapped - E30 M3 5-lug - 5x120 BBS RC090 (E39 Style 5) - TCK D/A coilovers 550/700 [SOLD]
            '87 535i - Vacuum brake conversion [SOLD]
            '93 525iT - 5-speed swap - 320k and counting
            '09 328xi - 6-speed

            Comment


              #7
              Originally posted by Gooch View Post
              There is also an adapter for the round diagnostic plug that will allow you to plug in an OBD-II scanner. I use one with a bluetooth OBD-II adapter and Torque.

              Link

              (For when the ebay link ultimately dies, just Google "20 pin to 16 pin BMW adapter" or "BMW to OBD" adapter)
              Thats exactly what i need to do, anyway i fixed the starting problem. With the key in position 2 i wiggled around the wiring harness and can hear the fuel pump turning on then off, i took off the intake manifold and redid the wiring harness nicely

              Comment

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