Page 4 of 4 FirstFirst 1234
Results 76 to 92 of 92

Thread: What is going on?

  1. #76
    Join Date
    Jan 2009
    Location
    San Jose, CA USA
    Posts
    1,001
    My Cars
    91 850
    Yes, indeed and agreed. I have two OEM sensors in the cart now.

  2. #77
    Join Date
    Jan 2009
    Location
    San Jose, CA USA
    Posts
    1,001
    My Cars
    91 850
    I would like to mark this thread as "CLOSED and RESOLVED".

    Root Cause: Possibly faulty fuel pump but definitely faulty CPS (crankshaft position sensor) on the driver's side.

    Symptoms: Driver's side huffing and puffing (misfiring underload). Eventually goes into an almost LHM but not quite because the driver's side still firing (fuel/spark at a very retarded rate). Attempting to clean the CPS sensors resulted in completely crank only and no start situation.

    Fix: Replaced with brand new BMW OEM CPS sensors. Warning, it's quite a bit of work replacing the bottom CPS sensor (the one for the driver bank). Refer to this link for more info on what people had to do to and how I tackled the power steering pump pulley bolts (https://www.bimmerforums.com/forum/s...Sensor-Install).

    Measuring the resistance across the bad CPS leads yield infinite resistance. Cable was chaffed and shorted.

    And last but not least, thank to you all the fellow 8ers for contributing their thoughts, ideas, and suggestions!
    You guys are awesome as always!

    Regards,

    Chris

  3. #78
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    ChrisFuture8, thanks for sharing your experiences with us, very helpful.

    I struggle with a similar problem. Diagnosis (DIS) shows both an ignition error (16: no CIS signal) as well as a oxygen sensor error (201: out of control) ON BOTH SIDES!
    Engine starts up fine, but then runs very rough and goes to LHM after a few minutes.
    Swapped DME's, AFM's, oxygen sensors, but no change. New spark plug cables, new fuel pressure regulators. Runs bad even with both oxygens sensors disconnected...
    During misfiring, clear fuel smell from the working exhaust, so running way too rich (CO too high). Possibly a hesitating ignition; I will first check wiring to the (new) coils.

    Any suggestions maybe?

  4. #79
    Join Date
    Sep 2008
    Location
    Santa Barbara
    Posts
    2,518
    My Cars
    91 Dinan860 & 91 850 6sp
    Albert... sounds like the O2 sensor plugs might be reversed...
    '91 Dinan 860 Stage III (soon to be Dinan TT 6L)
    '91 850i 6sp (mint)
    '91 850i 6sp (getting there)
    '90 Dinan 750iL TT stage III
    '94 850 CSi (being restored to factory perfect)
    '96 850Ci, The George Carlin car
    '94 840ci (4 short - obvious parts car), '91 850i parts car
    '73 3.0 csi, '08 535i, '95 318i
    ...and a few other non BMW cars

  5. #80
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Thanks, I thought about that, and actually tried swapping the connectors. Result was even worse.

    Update: after a cold start, it now only runs a few seconds before dying. So problem not related to the oxygen sensors. Coils get power from the DME (flashing test lamp), and fuel pressure at both sides is perfect (3.2 bar, dropping to 2.5 bar when sucking at the FPR hose). So there is spark and there is fuel, and the inlet systems has no vacuum leaks. DME's changed also. Mmm.

    CPS? Will check.

  6. #81
    Join Date
    Jan 2009
    Location
    San Jose, CA USA
    Posts
    1,001
    My Cars
    91 850
    Albert,

    This was my second bout with half engine running and during the troubleshooting process, I spent money on installing a lot of new parts and learned a lot during the process too. Thought I had the LHM troubleshooting process nailed down from the first failure but nope, there's more that I just learned.

    Anyways, with that out of the way, I hope you don't have to go down the route replacing parts endlessly.
    Start small and replace parts only when you have exhausted the diagnostic and troubleshooting steps.

    1: Have you checked both caps and rotors to make sure they are in functional condition?..ie: parts are not corroded out, worn down, etc.

    2: When was the last time the motor ran properly and since then, what has changed?

    3: Do you have a mechanic stethoscope to listen to the injectors. Some people have used a long screw driver and it should work but your ear is also next to the engine so it's not as accurate. The stethoscope is best. Typically, when you first fire up the motor, all injectors will run for several seconds before the bad side cuts out.
    The culprit to that could be the CIDS signal is not picked up by the DME. The remaining bank will stay running but very rich (as you have noticed at this point). Don't leave the engine running for long cause you will kill the cat converter and O2 sensor eventually.

    4: What is the condition of the ignition coils? They should not show any signs of puffing or have materials oozed out.

    5: While the motor is running wiggle and or slide the round doughnut ring of the CID sensor cable to see if it would make a difference.

    6: How difficult is it for you to start the motor? Does it catch within a second or two after cranking?

    7: If you were to check the impedance of the CPS sensors, the readings you should get should be around 550Ohms or so. And, of the three pins, only one combination of the two pins will register internal impedance. The rest will be infinite resistance...(wide open).

    Hopefully, one of the items above is the cause to your LHM. Once you're able to get both sides of the motor to run, and if it runs rough, then it's old parts that are going bad, but for now, an electronic sensor is not working at all.
    Last edited by ChrisFuture8; 03-05-2018 at 03:01 PM.

  7. #82
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Chris, thanks for your response. I am slowly running out of options...

    Symptom: engine starts instantly, to die after exacly one second.

    Measurements: fuel pressure is OK (both sides 3.2 bar), test lamp indicates activated injectors (both sides flashing), test lamps on coils flash, and pulled spark plug shows sparks (both sides, perhaps bit weak). So all conditions are present for a running engine.

    But after a second, all injectors go dead, and the engine stops. So the engine kills itself deliberately, but why..

    Replacements: used DME's, new mass flow sensors (Rilex), new coils (Bosch), 12 new spark plug cables incl CID donuts (both reading 0.2 ohm at connector), new crankshaft sensors (both reading 520 ohm at connector), new fuel pressure regulators.
    I measured the rotors (changed a broken one), the distributor caps look OK.

    Stomp test shows 1222 (oxygen sensor control, irrelevant in cold engine I guess), and 2247 (CID sensor).

    What would you do next? New distributor caps, perhaps causing too weak sparks?

    PS sorry to hijack your post..

  8. #83
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,366
    My Cars
    99 840ci Sport Indv
    Running for a couple of seconds and then stopping is most likely be due to a lack of signal from the Cylinder Identification Sensors on cylinders 6 and 12 - the system is designed to switch OFF the injectors if there is no signal to stop wash-down of cylinders that are not firing.

    A good signal from the sensors need:

    HT leads on 6 and 12 to be the correct type and diameter
    Cylinders 6 and 12 should be firing
    The sparkplugs fitted should be the OEM type (1K resistance I think, not sure)
    The sensors should be working and point the right direction axially
    The sensors need to be correctly connected to theDME's
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  9. #84
    Join Date
    Jan 2009
    Location
    San Jose, CA USA
    Posts
    1,001
    My Cars
    91 850
    [ PS sorry to hijack your post.. ]
    Not at all, Albert.

    Timm is right. Are you absolutely certain your CPS are connected to the correct plugs right underneath the oil catch?
    Is your car left hand or right hand drive? The CPS at the bottom position connects to the top left of the connectors at the bottom of the oil catch. For reference, left is driver's side and right is passenger side if you're sitting inside the car. The passenger's side CPS sensor is connected to the bottom right plug at the bottom of the oil catch.

    That leaves the two CID plugs open. The bottom left of the driver's side is for CID sensor for the driver's side (cylinder 12) and the top right plug is for the passenger's CID sensor that's from cylinder #6. Make sure these four cables are plugged into the correct plugs. Also, make sure your spark plug cables are plugged in the correct order at your distributor.

    If your distributor or caps are still usable, the motor should stay running if that's where the trouble is. It may not run as strong or smooth if those components are worn but your motor dies fairly immediately which again, points to the Cylinder ID sensor or CPS sensors either bad may not be plugged into the correct order. Since you just replaced those (assuming they are correct for the car), then verify the order of where they are plugged in.

    If your plugs are 1K Ohm, then they are the right resistance, if not, the motor will still run but just not as strong or smooth. That would be another problem.

  10. #85
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Quick update:
    Bank 7-12 with ignition fault: the (new) connector at plug 12 appeared badly corroded inside, possibly never made good contact. Replaced the connector, fixed, fault gone.
    Bank 1-6 with oxygen sensor fault: to diagnose the issue, I connected 2 digital volt meters to the sensors, and started the cold engine. Fired right up and ran fine. After a short while, both sensors went to closed loop (voltage fluctuating 0.1-0.9 V). But 5 minutes later, the 1-6 sensor voltage decreased to just above zero, and the CEL went on. I checked the wiring to that sensor, no obvious damage. Both fuel pumps pressure tested OK earlier, but could fuel punt 1-6 loose pressure after a while, causing the extremely lean mixture? That would explain this fault: I will test this.

  11. #86
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,366
    My Cars
    99 840ci Sport Indv
    The DME has a resistor network that would hold the Lambda Voltage at around 0.5V if there was a loss of connection between it and the Lambda sensor. That is why the voltage sits in the middle of the range when the engine is cold.

    Obviously if there was a short circuit (dampness in the connectors or insulation breaking down) then it could well drop to 0V. But, the main question must be: is the sensor/wiring at fault, or is the mixture really much too lean?
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  12. #87
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Quote Originally Posted by Timm View Post
    But, the main question must be: is the sensor/wiring at fault, or is the mixture really much too lean?
    Exactly.
    I see 3 causes for a very lean mixture: 1) too low fuel pressure, 2) "false" air sucked into inlet manifold, or 3) not firing injectors.
    1) is unlikely, as I tested the fuel pressure, but not in a running engine (will measure again and bridge both fuel lines to look for a change).
    2) is unlikely, as I removed the manifolds and sealed everything (will test difference left-right using a vacuum gauge).
    3) is unlikely (will test using stethoscope or test lamp).
    Interesting..

  13. #88
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Another update. Engine starts fine now, uses both banks, both oxygen sensors in closed loop, no more faults in the DME's.
    However, it does not run OK.
    DIS shows an injection signal (17 = ti) of 3.7 ms in bank 1-6, and 5.3 ms in bank 7-12. Spec says 3.8 idling. So it appears difficult to keep bank 7-12 running. I guess since one or more cylinders are not firing, either no fuel or no spark. Swapped MAF's, problem did not move. Vacuum OK.
    Will investigate, nearly there...

  14. #89
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,366
    My Cars
    99 840ci Sport Indv
    How did you fix the problem you had with the Lambda voltage dropping to 0V?
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  15. #90
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    Timm, I guess an oxygen sensor going to zero is the result of a DME shutting down fuel injection in a bank.
    During todays test drive, it happened a few times initially. the CEL came on, with 1247 (secondary ignition) fault.
    But somewhat later, the problem did not return, so I am puzzled.
    The one thing I did not renew are both distributors, perhaps worth a try to go for new Bosch units.

  16. #91
    Join Date
    Dec 2006
    Location
    Sunny Cali,
    Posts
    8,431
    My Cars
    6.5 second 69 Camaro
    Could also be the Health of your fuses in the trunk.

  17. #92
    Join Date
    Jan 2017
    Location
    The Netherlands
    Posts
    11
    My Cars
    850i
    We took the car for a tour organised by the Dutch BMW Classics Club.
    Although it ran on 12 cylinders all the time, without CEL, it still doesn't feel OK. DIS indicates an injection time of 4.8 ms at idle (both banks), spec says 3.8 ms. Hence also fuel consumption was way too high with 16 l/100 km during the slow tour.
    Next steps are a compression test of all cylinders, and analysis of oscilloscope images of the ignition.
    IMG_5144.jpg

Page 4 of 4 FirstFirst 1234

Similar Threads

  1. What is going on with my new rotors and pads???
    By Philo in forum 1992 - 1999 M3 (E36)
    Replies: 6
    Last Post: 03-22-2004, 12:02 PM
  2. What is going on, I got too much backpressure
    By ///Thirtytwo in forum 1992 - 1999 M3 (E36)
    Replies: 2
    Last Post: 08-12-2003, 02:31 AM
  3. What is going on?
    By Deadeye in forum General BMW sponsored by Intercity Lines
    Replies: 3
    Last Post: 07-14-2003, 09:47 AM
  4. What is going on?!
    By Kyle K. in forum Off-Topic
    Replies: 3
    Last Post: 08-02-2002, 04:54 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •