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M30b35 Runs too Rich for Smog

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    M30b35 Runs too Rich for Smog

    I recently shipped my 1989 325i convertible with an m30b35 out here from VA. I intend to BAR the car, but want it to pass the smog requirements before I start the BAR process.

    I have tried to smog it several times, but I keep failing for high HC and CO even when I adjust the AFM spring to trick it into running leaner and run 50% E85. The car definitely smells rich and that is confirmed the Smog machine. The car also has almost 0 NOX.

    ECU:
    My setup is an m30b35 out of a euro 1986 735i. The engine came running motronic 1.1 on a yellow 150 ECU. I now have it running motronic 1.3 on a maroon 179 ECU. I have been using an old school BAUM scan tool to read the fault codes and running values. This tool indicates that my 179 ECU is for an e32. I have also tried smoging my car using a 150 ECU, but it may not have adapted since I only drove it ~2 miles before smoging it.

    Q: Does the ECU need more driving time to learn?

    Wire Harness
    I am using my stock m20b25 wiring harness modified to reach the m30 plug locations.

    Ignition:
    The spark plugs are Bosch WR9LS and have a light coating of brown consistent with running rich, but are not fouled or overly sooty. I have a very strong spark at the plug, which leads me to believe my cap, rotor, wires, coil, and plugs are good.

    Vacuum:
    I have replaced everything that was causing a vacuum leak. I do not see any obvious leaks when smoke testing, and the system is holding good pressure.

    Exhaust:
    I am using the down pipes from a 1991 535i going into my stock 325i exhaust setup. I drove the car several miles on the freeway before checking my cat temperatures. It is 380F pre-cat and 510F post-cat, so ~130F temperature increase across the cat. I assume this indicates that my cat is working.

    Air Flow Meter
    I have tried multiple AFMs as well as adjusting the AFM spring tension with no positive changes. Everything has been reset to the stock factory position.

    Fuel Pressure
    I am using the stock 3.0bar FPR and have measured my fuel pressure as roughly 3.2bar (~3psi high). I have also tried using a 2.5bar FPR in an attempt to lean the engine out, but the ECU must be compensation by increasing the injector pulse width.

    Fuel Injectors
    I have Bosch injectors labeled 0 260 150 203, which comes up as e32 735i injectors.

    Sensors:
    I have a brand new Bosch coolant temp sensor. Throttle position sensor is reading idle/mid throttle/WOT correctly. The crank position sensor must be working for the car to run/drive, but is originally from an m20b25. The air intake temp sensor in the AFM is reading accurately according to the BAUM tool.

    I was previously useing a universal Bosch O2 sensor, but it is only mounted in the down pipe reading Cyl 4-6. I used the BAUM tool to scan my O2 sensor and it was sweeping from 0.1v-0.5v (indicating lean conditions). I have tried multiple AFMs and AFM spring settings with no positive results. I was getting no fault codes.

    I replaced my O2 sensor with a Bosch unit designed for an e34 m30b35. I also unplugged my ECU to reset any adaptions. I am not getting any CEL or fault codes. The BAUM tool indicated the sensor is sweeping, but the average is slightly above the desired 0.450 volts, which is consistent with a slightly rich condition.

    Q: Would reading only 1 bank cause a problem?
    Last edited by McGyver; 07-07-2017, 08:28 AM.
    sigpic
    1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
    1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
    1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

    #2
    Not sure whether reading only one bank would cause a problem (I'd assume not).

    Try driving it a bit further - I've found with mine that when I reset it, it takes a good week or so of driving for the ECU to adjust things so that it's all running perfect.
    My e30: OEM+ with M30B35

    Comment


      #3
      Ok, I have a bit more info now.

      I plugged in a different Motronic 1.3 (179) ECU from an e32 to eliminate the possibility that it was just a bad ECU.

      The scan tool indicates all of my O2 sensor readings occurred while the car was in closed loop mode. I used the BAUM scan tool to measure the voltage from my O2 sensor as sweeping from 0.470-0.670 volts, which indicates a rich condition. If I unplugged the O2 sensor, the voltage measured a static 0.450 volts (car went into open loop). I also used a volt meter to measure the voltage on the actual wires coming from the O2 sensor, which exactly mirrored what I saw on the BAUM tool. This indicates my O2 sensor is working, but shows that my car is rich.

      I was able to use a 5-gas analyzer to get some actual info on my car.

      These are the current CA smog standards, which indicate that emission requirements are not that much different between m20 and m30 engines so it would not be significantly easier to get it smogged as an m30 car:

      Engine-------------m20b25------------m30b35
      Speed (mph)----15------25----------15-------25
      HC (ppm)--------108----83----------102------77
      CO (%)----------0.50----0.40--------0.68-----0.55
      NOx (%)---------767----706---------748------687

      Here are my baseline numbers with roughly 25% E85 mixed with 75% regular pump gas (max of 10% ethanol):

      Speed (mph)----Idle-----15------25
      HC (ppm)-------450------168----153
      CO (%)----------6.0------3.3-----3.57
      CO2 (%)--------10.8-----12.8----12.8
      O2 (%)----------0.5------0.0-----0.0
      NOx (%)--------8---------275----280

      Using a Lambda Calculator, I get a value of 0.898. This indicates a very rich condition that is beyond limits of a catalytic converter to "clean up". So although I may have a bad cat, I have some other problem that needs to be fixed first.

      Since I know I am very rich, I tried to introduce a vacuum leak in various ways to clean it up:

      Condition---------Oil Cap Off------AFM Idle Screw Out
      Speed (mph)-----Idle-----------------15---------25
      HC (ppm)--------520------------------168-------160
      CO (%)-----------0.04----------------3.8--------3.59
      CO2 (%)---------12.2-----------------12.8------12.8
      O2 (%)-----------3.5------------------0.0-------0.0
      NOx (%)---------46------------------186--------248

      After putting the AFM idle screw back in, I removed the vacuum line on the FPR. The resulting 15 and 25 mph tests were identical to the numbers with the AFM idle screw removed.

      I don't think it's a misfire because all of my plugs are in good condition and look the same. In fact, none of them look sooty as if they are in an overly rich environment.

      So my conclusion is that my car is just too rich. What input have I missed that would cause the car to be this rich or burn incompletely? Leaking fuel injector? Bad injector spray pattern? Something strange with using the e30 m20b35 wiring harness on an m30 with an m30 ecu? But both are Motronic 1.3?

      I am completely confused.
      Last edited by McGyver; 07-10-2017, 11:39 AM.
      sigpic
      1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
      1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
      1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

      Comment


        #4
        Could the euro b35 be like the euro b34? It was known as the dirty m30 because it wouldn't pass emissions and didn't have a cat iirc


        1989 325is l 1984 euro 320i l 1970 2002 Racecar
        1991 318i 4dr slick top


        Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
        Vintage race car revival (2002 content)
        Mtech 2 turbo restoration
        Brilliantrot slick top "build"

        Comment


          #5
          M30b35 Runs too Rich for Smog

          Low compression will run rich, check that as step 1, immediately after engine shutdown.

          Make sure your coolant temp sensor is good or it will run rich assuming engine is cold.
          I believe blue temp sensor is for ecu, brown is for gauge.

          Also do a valve adjustment for good measure. While engine is hot as well.

          I had a similar problem on my m30 b35, US version. I had a poor idle and poor throttle response, noticeable drop in torque @ 3k rpm. Ended up being crappy injectors with 240k miles and horrible garden hose spray pattern. I swapped in yellow 4 pintle bosch injectors (0280155700) and the problem went away. That's the last thing I would check tho
          Last edited by pandaboo911; 07-10-2017, 03:21 PM.

          Comment


            #6
            Originally posted by ThatOneEuroE30 View Post
            Could the euro b35 be like the euro b34? It was known as the dirty m30 because it wouldn't pass emissions and didn't have a cat iirc
            I would assume no for 2 reasons:

            1) the "dirty" euro m30b34 didn't come with a cat, but was also a 10:1 compression compared to the US 8:1 compression

            2) I don't believe BMW offered multiple compression variants of the m30b35, all should be 9:1. The difference is that the european e32 got the b35 in 1986 while the US e32 got the b35 in 1988
            sigpic
            1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
            1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
            1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

            Comment


              #7
              Originally posted by McGyver View Post
              I would assume no for 2 reasons:



              1) the "dirty" euro m30b34 didn't come with a cat, but was also a 10:1 compression compared to the US 8:1 compression



              2) I don't believe BMW offered multiple compression variants of the m30b35, all should be 9:1. The difference is that the european e32 got the b35 in 1986 while the US e32 got the b35 in 1988


              Ah okay


              1989 325is l 1984 euro 320i l 1970 2002 Racecar
              1991 318i 4dr slick top


              Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
              Vintage race car revival (2002 content)
              Mtech 2 turbo restoration
              Brilliantrot slick top "build"

              Comment


                #8
                it may be worth your while to register your car in a county that is "transfer of ownership only" for smog.. get a friend's address and open a local PO box. I did that with an old toyota pickup and never had to smog it, even though I lived in San Jose. Even when I was pulled over for lane changes or whatever the cop felt like being a dick4 they never asked why my license and registration addresses were different

                unfortunately your car won't be BAR legal because your donor motor is supposed to be out of a car the same model year or newer.


                it's a Kenny Powers quote on wheels

                Comment


                  #9
                  I think there is a form on the dmv website to report people like you.
                  Stuff like that, i would do every shady shit I could but heavy fines are too scary.

                  Comment


                    #10
                    Do you have to do annual smog tests?

                    An alternative is leave the registration as is and sand the 3.5 off the inlet manifold... no one ever notices down here ;) Even when I attended a local car show, BMW enthusiasts walked past the car for hours before someone noticed that the car wasn't M20 powered.

                    My e30: OEM+ with M30B35

                    Comment


                      #11
                      Originally posted by Das Delfin View Post
                      it may be worth your while to register your car in a county that is "transfer of ownership only" for smog.. get a friend's address and open a local PO box. I did that with an old toyota pickup and never had to smog it, even though I lived in San Jose. Even when I was pulled over for lane changes or whatever the cop felt like being a dick4 they never asked why my license and registration addresses were different

                      unfortunately your car won't be BAR legal because your donor motor is supposed to be out of a car the same model year or newer.
                      I still own property in VA. So for the time being, I'm going to leave it registered there until it runs clean enough to BAR.

                      And yeah, I may run into some problems at BAR because the engine block does have some ID numbers, but they are pretty hard to see in a bad location and all rusted over. I have some old info for a 1991 535i that I parted out in VA, so I'm hoping that will be enough to argue that the engine is acceptable.

                      Originally posted by LowR3V'in View Post
                      I think there is a form on the dmv website to report people like you.
                      Stuff like that, i would do every shady shit I could but heavy fines are too scary.
                      They do, so I'm working on getting everything on the level. It's just taking longer than I thought.

                      [QUOTE=lukeADE335i;4806050]Do you have to do annual smog tests?

                      An alternative is leave the registration as is and sand the 3.5 off the inlet manifold... no one ever notices down here ;) Even when I attended a local car show, BMW enthusiasts walked past the car for hours before someone noticed that the car wasn't M20 powered.

                      Bi-annual. I intend to BAR it so that it's 100% legal, but part of the process is the sniff test. So I can't start BARing it until it's running clean.
                      Last edited by McGyver; 07-19-2017, 10:42 AM.
                      sigpic
                      1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
                      1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
                      1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

                      Comment


                        #12
                        measure your

                        - fuel flow rate
                        - manifold vacuum at idle
                        cars beep boop

                        Comment


                          #13
                          Originally posted by kronus View Post
                          measure your

                          - fuel flow rate
                          - manifold vacuum at idle
                          How would I measure my fuel flow rate? Is that the same as my fuel pressure?

                          I've almost finished going through checking the entire fuel injection and ignition systems. I just bought a compression tester to measure that. I'm basically going through all of the steps in the Bentley one by one.

                          However, I am starting to believe that my issue has to do with the O2 sensor only measuring one bank. Based on my research of how the DME works, I think the DME is looking for pulses as each exhaust stroke passes the sensor. The DME would then interpret the voltage associated with each stroke to determine if the engine is rich/lean. I am assuming the DME is confused because it is only seeing 3 out of 6 expected strokes, so it's math is wrong.

                          When I use a volt meter to watch my O2 sensor fluctuate, the volt meter is showing some average over time, not the instantaneous pulses. To see the pulses I would have to use an oscilloscope. That would explain why the voltage on my meter indicates a rich condition, but the DME wants to still dump in extra fuel.

                          Then again, I might have it all wrong. An easy test would be to see how the car runs with the O2 sensor unplugged to see if open loop mode is combusting more efficiently. Likewise, I could just weld my O2 sensor in correctly...
                          sigpic
                          1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
                          1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
                          1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

                          Comment


                            #14
                            this is the 80s dude

                            the o2 sensor is not sensitive enough to differentiate between 3 and 6 exhaust pulses



                            for fuel flow rate, the procedure is documented in the bentley. involves pulling the rail, sticking some cups under it, turning the fuel pump on for x seconds and measuring mL of fuel in the cups.
                            cars beep boop

                            Comment

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