Results 1 to 22 of 22

Thread: 2.7 - 86 325 Engine Sputters/lags & Rough start

  1. #1
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325

    2.7 - 86 325 Engine Sputters/lags & Rough start

    Well, I have been having certain issues with my 3 series.

    On heavy acceleration or driving normal the car sputters, jerks and picks up power right after. I was thinking it could be a bad fuel pump, or faulty injector.

    I have tried a few over the counter remedies like fuel injector cleaner and switching up to higher octane.

    Also another issue that i am having is on cold starts. The engine wants to turn over but it won't or it will start and die off immediately. Its starting to concern me because i work far and i would hate to be stranded.

    Any recommendations? I would appreciate any input reguarding the issue.


    More Specs on the car,
    Manual
    2.7 Engine
    230xxx miles

    Thanks,
    Ashar

    Cheers!

  2. #2
    richardodn's Avatar
    richardodn is offline Old Guy BMW CCA Member
    Moderator
    Join Date
    Nov 2008
    Location
    Lakewood, CO
    Posts
    9,942
    My Cars
    20 440ix cab, 12 X3 35ix
    First things first. Check for vacuum leaks. The sputtering off idle changing to power as the RPMs increase is a typical symptom.
    "Howdy, Folks!"

    1986 Delphin 528e - Roof rack equipped lumber hauler.
    1989 Zinnoberrot 325iX Sedan - I miss this car. (Deceased)
    1998 Avus Blau 328iC - Someone else's project now
    2008 Platinum-Beige X3 3.0si - Current project
    2012 Alpine White X3 xDrive35i - My new snowmobile.
    2020 Estoril Blue 440i xDrive cabrio - This car is a blast to drive.

  3. #3
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    No vacuum leaks.

  4. #4
    Join Date
    Dec 2004
    Location
    Huntsville, AL
    Posts
    25,923
    My Cars
    87 325is
    Quote Originally Posted by 86 325e View Post
    No vacuum leaks.
    The only way you can say that with any credibility is if you've just had a smoke test run on the intake. Otherwise you don't know if there are any intake leaks.

    Intake leaks are the most common cause of hard cold starts. But they probably aren't the cause of the driveability issues. For those I'd look to the fuel system (run the tests in the Bentley), the AFM, the timing reference sensors, or the ignition wires/plugs/rotor/distributor cap.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

  5. #5
    Join Date
    Dec 2007
    Location
    Marietta, ga
    Posts
    1,143
    My Cars
    e30 x2 93e36 94e34
    do a tune up on your car

  6. #6
    Join Date
    Jul 2010
    Location
    CT
    Posts
    283
    My Cars
    X84-318 X86-325 89-325i
    I have/had the same issue at idle and same starting conditions. I did the fuel filter, coil, plugs, dist cap, rotor, wires, and it's better. Not perfect, but much better. I actually think some of it might be my (bad)cat.

  7. #7
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    Could it be my fuel pump?

    the car starts cold, goes to 500rpm and dies out. The car starts to smell like fuel.
    Last edited by 86 325e; 01-11-2011 at 08:18 AM. Reason: Automerged Doublepost

  8. #8
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    Still having problems.

  9. #9
    Join Date
    Feb 2010
    Location
    MYRTLE BCH SC
    Posts
    1,045
    My Cars
    86 porsche 930, 88 325is
    could be a leaking injector. does your car have a cold strat valve? have you checked for fuel leaks? check for leaks at the fuel pump too.
    [__] RUNNING: [__] NOT RUNNING: 86 PORSCHE 930
    [__] RUNNING: [__] NOT RUNNING: 88 BMW 325is 200K+
    [__] RUNNING: [__] NOT RUNNING: 2000 MERCEDES E320 WAGON
    [__] RUNNING: [__] NOT RUNNING:99 GRAND CHEROKEE 160K::
    [_:_] RUNNING: [__] NOT RUNNING: mazda B2200

  10. #10
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    I replaced my pump and my fuel filter and i put in a new battery. The car starts on the day i get it fixed. The next day it hesitates a little and starts to sputter again. Today I go to start it, it wouldnt start (about 28 degress F) I go to start it after school, and its starts up right away. What could the problem be?

    I really need help ASAP!!! Please!!!
    Last edited by 86 325e; 02-28-2011 at 09:42 PM. Reason: Automerged Doublepost

  11. #11
    Join Date
    Jan 2011
    Location
    Minneapolis, MN
    Posts
    17
    My Cars
    1985 325e
    I would check your charging system. Similar thing was happening to me, idling funny then quitting. Lights went dim on the interstate last week and car quit running. Replaced alternator but that wasn't it. Turned out to be the stupid battery cluster bulb was burned out so interrupted the circuit. It's a shot in the dark, but...

  12. #12
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    My battery cluster bulb still works.

  13. #13
    Join Date
    Dec 2004
    Location
    Huntsville, AL
    Posts
    25,923
    My Cars
    87 325is
    I'm sure that you hoping for an answer that says "Replace this part and all will be well'. But on a 25 year old car it seldom works out that way. There can be a single cause, but more often the problem will be the result of several lesser causes. You can throw parts at it and hope for a favorable outcome, but the desired result will be achieved faster and cheaper by a systematic approach.

    Idle or hard starting problems are most commonly caused by intake leaks and/or
    a sticky or defective Idle Control Valve (ICV). The only reliable method of
    locating intake leaks is to have a smoke test run on the intake and crank case
    and to test the brake booster with a gage and vacuum pump. The complete list
    of possible causes of an intake leak is:

    Intake boot
    Throttle body gasket
    ICV hoses & connections
    Brake booster, hoses, and connections
    Crank case breather hose
    Evaporative control hoses, valve, and expansion tank
    Fuel pressure regulator & hose
    Injector seals
    Valve cover gaskets & bungs
    Oil filler cap
    Dip stick o-rings
    Oil return tube o-rings

    While leaks in some of those can be found by inspection or by spraying carb
    cleaner on suspect areas, not finding leaks that way doesn't eliminate the
    possibility. Only a smoke test will really work.

    Once the possibility of intake leaks is eliminated, the ICV needs to be
    removed and cleaned with carb cleaner until the vane inside moves freely. When
    the ignition is switched on you should be able to feel vibration from the
    ICV. If no vibration the ICV is bad, there's a problem with its wiring or
    connector, there's a problem with the TPS, or the DME (or Idle Control Module
    (ICM) on an ETA car) is faulty.

    For the DME (or ICM) to control idle, the idle switch in the TPS must work
    correctly. The switch should close when the throttle stop is 0.030-0.060" off
    the idle stop screw.

    The fuel system should be tested via the suite of tests in the Bentley manual
    as invalid rail pressure can be a contributor to idle and starting problems. A
    simple injector check is to pull the injectors, jumper the fuel relay to run
    the pump, and see if the injectors are leaking. You can also point the
    injectors into a towel, remove the coil wire, and crank the engine to see if
    all of the injectors appear to be spraying in a similar fashion. The best
    approach to possible injector problems is to have the injectors cleaned and
    flow tested. Since raw fuel can or will be released in these tests, have a
    fire extinguisher handy.

    On an ETA engine, the time-temperature switch should be tested or replace with
    an new unit and the cold start valve check for operation and leaks.

    The O2 sensor can be a contributor to idle problems. The O2 sensor is a
    scheduled maintenance item with a useful life of no more than 100k. If the
    sensor has that mileage or more (or is of unknown age), replace it.

    The AFM can be a contributor. If the vane doesn't move freely or the
    resistance track is worn the DME may be receiving invalid data from the
    AFM. And if someone has fiddled with the bypass air adjustment the DME may be
    unable to stabilize idle. The bypass air adjustment should only be adjusted
    per the procedure in the Bentley and with an exhaust gas analyzer. And even
    then everything else associated with engine management has to first be
    operating properly. If the AFM becomes a suspect, replacement with a good used
    unit is the best approach.

    Improperly adjusted or malfunctioning valves will affect idle and starting. As
    can compression issues from ring or cylinder wear. A valve adjustment is
    called for every 15k. A useful diagnostic is to run compression and leak down
    tests on the engine. And aged ignition wires, plugs, distributor cap, or
    rotor can cause problems. Insulation does break down with time and heat. And
    since the youngest E30 is going on 19 years old, if the ignition system is
    original or the plugs are old replacement is indicated.

    Although not usually a problem, a bad DME temp sensor is a possibility. That
    generally won't cause an unstable idle, but can cause hard cold or hard hot
    starts and/or a rough idle. As can problems with the timing reference sensors.

    When all other possibilities have been eliminated and idle or starting
    problems persist, replacement of the DME, or if applicable the ICM, is
    indicated.
    Last edited by thejlevie; 03-05-2011 at 01:51 PM.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

  14. #14
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    When I start the car it smells like fuel outside.

  15. #15
    Join Date
    Sep 2010
    Location
    Olive Branch, MS
    Posts
    45
    My Cars
    1986 325es
    Great information I need to keep tabs on here. Thanks.

    Quote Originally Posted by thejlevie View Post
    I'm sure that you hoping for an answer that says "Replace this part and all will be well'. But on a 25 year old car it seldom works out that way. There can be a single cause, but more often the problem will be the result of several lesser causes. You can throw parts at it and hope for a favorable outcome, but the desired result will be achieved faster and cheaper by a systematic approach.

    Idle or hard starting problems are most commonly caused by intake leaks and/or
    a sticky or defective Idle Control Valve (ICV). The only reliable method of
    locating intake leaks is to have a smoke test run on the intake and crank case
    and to test the brake booster with a gage and vacuum pump. The complete list
    of possible causes of an intake leak is:

    Intake boot
    Throttle body gasket
    ICV hoses & connections
    Brake booster, hoses, and connections
    Crank case breather hose
    Evaporative control hoses, valve, and expansion tank
    Fuel pressure regulator & hose
    Injector seals
    Valve cover gaskets & bungs
    Oil filler cap
    Dip stick o-rings
    Oil return tube o-rings

    While leaks in some of those can be found by inspection or by spraying carb
    cleaner on suspect areas, not finding leaks that way doesn't eliminate the
    possibility. Only a smoke test will really work.

    Once the possibility of intake leaks is eliminated, the ICV needs to be
    removed and cleaned with carb cleaner until the vane inside moves freely. When
    the ignition is switched on you should be able to feel vibration from the
    ICV. If no vibration the ICV is bad, there's a problem with its wiring or
    connector, there's a problem with the TPS, or the DME (or Idle Control Module
    (ICM) on an ETA car) is faulty.

    For the DME (or ICM) to control idle, the idle switch in the TPS must work
    correctly. The switch should close when the throttle stop is 0.030-0.060" off
    the idle stop screw.

    The fuel system should be tested via the suite of tests in the Bentley manual
    as invalid rail pressure can be a contributor to idle and starting problems. A
    simple injector check is to pull the injectors, jumper the fuel relay to run
    the pump, and see if the injectors are leaking. You can also point the
    injectors into a towel, remove the coil wire, and crank the engine to see if
    all of the injectors appear to be spraying in a similar fashion. The best
    approach to possible injector problems is to have the injectors cleaned and
    flow tested. Since raw fuel can or will be released in these tests, have a
    fire extinguisher handy.

    On an ETA engine, the time-temperature switch should be tested or replace with
    an new unit and the cold start valve check for operation and leaks.

    The O2 sensor can be a contributor to idle problems. The O2 sensor is a
    scheduled maintenance item with a useful life of no more than 100k. If the
    sensor has that mileage or more (or is of unknown age), replace it.

    The AFM can be a contributor. If the vane doesn't move freely or the
    resistance track is worn the DME may be receiving invalid data from the
    AFM. And if someone has fiddled with the bypass air adjustment the DME may be
    unable to stabilize idle. The bypass air adjustment should only be adjusted
    per the procedure in the Bentley and with an exhaust gas analyzer. And even
    then everything else associated with engine management has to first be
    operating properly. If the AFM becomes a suspect, replacement with a good used
    unit is the best approach.

    Improperly adjusted or malfunctioning valves will affect idle and starting. As
    can compression issues from ring or cylinder wear. A valve adjustment is
    called for every 15k. A useful diagnostic is to run compression and leak down
    tests on the engine. And aged ignition wires, plugs, distributor cap, or
    rotor can cause problems. Insulation does break down with time and heat. And
    since the youngest E30 is going on 19 years old, if the ignition system is
    original or the plugs are old replacement is indicated.

    Although not usually a problem, a bad DME temp sensor is a possibility. That
    generally won't cause an unstable idle, but can cause hard cold or hard hot
    starts and/or a rough idle. As can problems with the timing reference sensors.

    When all other possibilities have been eliminated and idle or starting
    problems persist, replacement of the DME, or if applicable the ICM, is
    indicated.

  16. #16
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    so i figured it was a cold start injector, but would it cause the sputtering and jerking?

  17. #17
    Join Date
    Apr 2011
    Location
    Richmond, IN
    Posts
    21
    My Cars
    1999 BMW M3 'vert
    Quote Originally Posted by 86 325e View Post
    so i figured it was a cold start injector, but would it cause the sputtering and jerking?

    Did you replace/ disconnect the cold start valve? Did this fix your issue?

    I am working with a similar situation on a car that has been sitting for a LOOOONG time. It is currently missing the VC breather hose, so I am hoping that my cold start issues will be fixed when that is in place. If not, I am suspecting the CS valve. My car runs fine when warm, but dies when going into gear (load) while cold- seems to be running too rich when the engine is cold.

    I have checked most of the basic things and done a tune-up so far.

  18. #18
    Join Date
    Apr 2011
    Location
    claremore, ok. 714017
    Posts
    361
    My Cars
    1987 bmw 325
    i had a bad idle problem too not too long ago and even though the primary problem i was trying to fix turned out to not be a problem, eta car just are ment to idle lower. anywhoo i found alot of things that needed replacement in the mean time. check your air flow meter make sure the resistance is consistent and even as the door is open and closed. check fuel pressure. where is it idling at? on the eta cars there is a switch/sensor in the tstat that has 2 spade connectors if its out then your car will idle high around 900-950 rpms all the time and it will run really rich. its meant top close when the coolant gets to a certain temp. check your o2 sensor make sure its good. it will cause the problems your describing. i didnt believe these cars needed the o2 sensor so much, ive never owned a car that has a working one and they all ran and drove fine but not these cars. if your fuel pump is going it will probably make a high pitched whining sound. but remember these fuel pumps are noisy to begin with. exactly how noisy is normal seems to vary from car to car almost. i hope some of this helps if you havent checked these things already.

  19. #19
    Join Date
    Apr 2011
    Location
    Richmond, IN
    Posts
    21
    My Cars
    1999 BMW M3 'vert
    Well, I believe my issues are a combination problem as well. It seems to be running better than it ever has now that I shorted the coolant temp. sensor and also disconnected the O2 sensor and cold start valve. I think I will replace all 3 of these sensors and I should be back in business.

    I also took apart the AFM and made sure the wiper arm and everything was working correctly then cleaned it with some contact spray. I may try to check out the TPS as well if these 3 sensors don't clear everything up. These cars are getting OLD. every connector I have removed has looked very cruddy and required cleaning so it is hard telling what exactly will fix it completely.

  20. #20
    Join Date
    Oct 2010
    Location
    Chicago, Illinois
    Posts
    220
    My Cars
    1986 BMW 325
    For some reason my car doesnt sputter at all anymore. The only problem is a rough start. Once the car has went through a warm up during the day the car starts up quickly every other time that day

  21. #21
    Join Date
    Sep 2014
    Location
    byhalia, ms
    Posts
    1
    My Cars
    1986 bmw 325e E30

    what ive done

    I've had the exact problem for the past 3 years with my 86 325. I mean you have done the best describing my problem. I'll tell you what I have replaced to save you the trouble and tell you what to eliminate. Ive replaced feul pump, fuel filter, fuel pressure regulator, cold start injector, coolant temp sensor, distributor cap and button, TPS, Mass air flow.. or is that the map sensor... thing that connects to the intake boot lol $200 alone, oxygens sensor, and i think thats it. I bought every part new and unless i bought a defected part somewhere these parts can be eliminated for sure. Keep in mind i only payed $500 for this care and it has 400,000+ miles original motor.

    - - - Updated - - -

    Oh yes and even if it quit... it will be back I promise. Had this problem long enough to know. Summer runs and idles GREAT above 80 degrees f. Come winter its my POS lol.

  22. #22
    Join Date
    Mar 2019
    Location
    Billings MT
    Posts
    1
    My Cars
    1986 BMW 325
    My 1986 325 with the 2.7, as your driving it down the road it will feel like it cuts out but then out of nowhere it takes off and it continuously does it. Any ideas what it could be, replaced the fuel filter.

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
  •