1988 IX running very rich, cutting out.

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  • dubrooks
    Noobie
    • Apr 2012
    • 19

    #1

    1988 IX running very rich, cutting out.

    A year or so ago I ran into a deer with the IX. It fell onto the hood of the vehicle, busting out the two left headlights, and landing denting in the hood pretty well. Ever since, the car has run extremely rich. Car ran like a champ before the accident. Radiator was junk, replaced with one I had around. had to pull the front part of the car out with a forklift, it was bent in so that the radiator was pressed against the engine fan. Put on a new fan and clutch as well.

    Vacuum smoke test: good, no leaks
    Timing belt, water pump: New, timing is spot on. Checked multiple times.
    Coolant sensors: New
    Crank sensor: tried others.
    -as an aside, the current one on the car is the original, it's solid metal and seems to touch against the mounting bracket.
    Airflow sensor: Swapped with known working ones out of three different 325i.
    Spark: fat and blue. sparking on all cylinders. New plugs.
    Distributor, wires: good. Swapped.
    Plugs: ALL carbon fouled, very rich smelling exhaust
    Check engine code: none.
    Injectors: cleaned, swapped, seem to spray fine and not leak
    Cat is clean, dropped exhaust. Swapped exhaust. 02 sensor is new.
    Alternator and voltage regulator: good. Wiring: good. 13+v at battery.
    Fuel pressure: good.
    FPR: Good, swapped.
    FPR vacuum: good.
    CCV: Good.
    ICV:swapped with known working. No luck.
    Grounds: one frayed. Replaced, cleaned mounting points, beefed up ground wires. Hood ground is now gone.
    Compression: about 10-20 psi low on all cylinders, leak-down test indicates worn piston rings, not blown head gasket. Head gasket was new before accident.

    When the car is started, it fumbles all over itself, specific amounts of 'gas' (pedal push) will make it rev up for a minute or so, but it will not idle on it's own for more than a few seconds, sounds like a stroker off timing or a lawnmower lol.
    If I disconnect the airflow sensor, I can drive it, kind of. Anything over half pedal-push will make the car cut out, but between 1/3 and 1/2 pedal push the car seems to behave. Doesn't sound like it's missing, there's just almost no acceleration to be had.

    I'm running out of ideas over here. It has to be something electrical, and it has to have been damaged by the accident. The deer hit the front left side of the car pretty well, by the airflow sensor. I've checked through the wires looking for visible damage to no avail, found this and that for wiring quirks and corrosion, which I've fixed. Added electric grease to all the connections.

    A fusible link can't cause a rich-run condition, can it? battery's been in/out IDK how many times. Re-wired the posts too. Worth my time to re-wire the c191? Another thing I was thinking was the three relays, main, 02, etc, they took a smack when the deer hit but I can't find any damage. Not quite sure how to multimeter those.

    My electrical troubleshooting knowledge is limited. Any advice would be awesome.
    Last edited by dubrooks; 11-24-2013, 07:12 PM.
  • AndrewBird
    The Mad Scientist
    • Oct 2003
    • 11892

    #2
    A bad o2 sensor will make it run rich. Looks like the only thing you haven't listed.

    Comment

    • spdracrm3
      E30 Modder
      • Sep 2009
      • 959

      #3
      Originally posted by NitroRustlerDriver
      A bad o2 sensor will make it run rich. Looks like the only thing you haven't listed.
      usually an O2 sensor will not affect and engine at start-up or even a short while after as it takes awhile for the element in the sensor to reach operating temp so the ECU will not even look at the signal from it , in fact a good test for an O2 is to restart after its been running poorly and if it runs ok then starts to run bad again after awhile its a good chance it the O2 feedback causing the problem.

      this is a wierd issue due to it starting after the accident so need to really scrutinize everything that got hit for damage/shorting/broken wires(especially grounds ,including to the ECU) (check multi-pin plug under intake manifold for jarring loose or corrosion on pins), if the main or fuel pump relays that were hit and had issues it wouldnt start ie no fuel pressure, no power to ECU , but if the O2 relay is shorted it might have caused damage to the ECU control circuits. im thinking its time to check all pins at the ECU for correct signals and voltages/grounds ,if nothing turns up unusual the try another known good ECU.


      ECU pinout 1.1 &1.3
      Angus
      88 E30M3 X2
      89 325IX
      92 R100GS/PD
      :)

      Comment

      • 4x4_e30
        Advanced Member
        • Sep 2013
        • 164

        #4
        I'd put all my money on that c191 connector. But I don't have any money :(

        Comment

        • SmokeE30
          E30 Mastermind
          • Jun 2009
          • 1730

          #5
          Check ecu pins for proper voltage and or swap in a known good ecu
          Shawn @ Bimmerbuddies
          Bimmerbuddies LLC
          717-388-1256
          2971a Roundtop Rd, Middletown PA 17057
          bimmerbuddiesllc@gmail.com

          Comment

          • dubrooks
            Noobie
            • Apr 2012
            • 19

            #6
            Cool, thanks for the advice. I will see what I can do about checking the pins. I have two spare computers, both out of 87 325is. The IX is a 1988 (harness, body, etc) with a 1987 engine from a 5-speed swap. Will the 325is computers work? if so I've tried one of them.

            The deer definitely hit the c191, but there is no visible damage other than being bent back a little. Will consider re-wiring after I check the pins. Will keep this updated with results from that when I can get her pulled into the shop to work on it. Getting cold out. Appreciate the input.

            Comment

            • spdracrm3
              E30 Modder
              • Sep 2009
              • 959

              #7
              another good info PDF on the ECU http://e30-talk.com/e30-wikipedia/t-...sch-76772.html its in English

              any 153 or 173 ECU should work here a list of compatible ECU's
              Angus
              88 E30M3 X2
              89 325IX
              92 R100GS/PD
              :)

              Comment

              • AndrewBird
                The Mad Scientist
                • Oct 2003
                • 11892

                #8
                Originally posted by spdracrm3
                usually an O2 sensor will not affect and engine at start-up or even a short while after as it takes awhile for the element in the sensor to reach operating temp so the ECU will not even look at the signal from it , in fact a good test for an O2 is to restart after its been running poorly and if it runs ok then starts to run bad again after awhile its a good chance it the O2 feedback causing the problem.
                Good point, didn't think about that.

                Comment

                • dubrooks
                  Noobie
                  • Apr 2012
                  • 19

                  #9
                  had some time to do some tinkering today... went through the bently fuel system control unit electrical tests. only found a couple things that might be of attention:

                  1: The air flow sensor starts at 640 ohms and ranges upwards to 930 when the starter is actuated (I didn't have a helper.) I feel as though this is normal resistance though... ?

                  2: The "cylinder identification sensor" (wtf???) says it should be less than 1 ohm resistance, mine is 1.8ohms. Not even sure what this sensor is really. Will do some research.

                  Grounds are all set, so is power to computer. injectors work fine, IAS has exact resistance. Didn't get to test purge valve..

                  I also checked the resistance of my plug wires, which are about 1k ohms (they should be 0....) I know that's high but the car ran fine before the accident. resistance of the coil is a little high but nothing crazy.

                  also tripple checked crank sensor resistance, it's fine.

                  Any thoughts appreciated.
                  Last edited by dubrooks; 12-04-2013, 07:43 PM.

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