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Thread: Getting a CIS E21 to run

  1. #1
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    Getting a CIS E21 to run

    First things first, I'm a BMW noob let alone anything with CIS.

    I've read a ton of different threads on here that have helped me get a friends 1979 320i running when cold but figured I'd make my own incase I'm missing something very obvious to someone more knowledgeable then me.

    As stated the car is a 1979 320i that I'm helping a friend get running. Car has sat for a few years and when I first started on it wouldn't run at all. Someone else has already had their hands on the car before me and removed all the fuel system up to the fuel distributor and had a Jerry can with a Walbro 255 feeding the fuel distributor directly.

    So on to the problems.

    1- With this fuel setup as soon as the pump is given power the injectors immediately start spraying no matter the position of the 3mm allen screw by the fuel distributor but I have been able to make it run like this.

    2- After cleaning the plunger in the fuel distributor I can get the car to start and rev happily when cold but after 15-20 seconds the revs will start to drop to the point where it will not run no matter the throttle input or position of the 3mm Allen bolt and will let the odd backfire out the intake (havent checked timing yet but it's on the to do list)

    3- I'm in the process of sorting out vacuum lines as I've read these engines are very finicky when it comes to vacuum leaks. I doubt my issues could be that easy though

    4- After reading a number of different posts some seem to point to the cold start relay? What's everyone's opinion on that?

    Thanks in advance and hopefully I'm missing something simple, I'd like to get this running so I can get back to my own projects Haha.

  2. #2
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    Cool

    Could be the pressure relief valve in the fuel distributor is stuck mostly closed causing High Pressure or Shimmed too much, could be the Fuel Pump is adding too much fuel for pressure relief valve to let the fuel return to the tank,, Fuel Pressure measured at the Fuel Distributor should be 60-74 psi,, injectors open ~ 44 psi on 80-83, the fuel distributor flexible fuel plate might be stuck open due to debris. my fuel distributor flexible fuel plate got stuck open once and Fuel pressure was 100 psi , So much pressure at startup some times the fuel injectors were launched out of the Cylinder Head,,rebuilt fuel distributor solved that. Cold Start Valve adds Fuel so long as the starter motor is engaged and then stops when warmed up supposedly, internal combustion motors like rich startups--no exceptions either. Fuel distributor rebuild is in Faq's,, 77 -79 Fuel distributors are not adjustable, 80-83's are adjustable per injector feed hole.



    Randy
    Last edited by 320iAman; 05-12-2019 at 12:08 PM.

  3. #3
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    1- must be resolved, otherwise it will never work properly. If you cannot get the 3mm allen to stop the fuel to the injectors, here are other possible culprits ::

    a) the fuel distributor's meter piston/plunger is sticking in a partially 'open' position, or is damaged.

    b) the air-flow meter plate is not at proper rest position. Proper rest position is to be level (rest height) and centered in it's bore, not scraping/catching on the edges. It is adjustable if needed (rest height and centering).

    c) bad o-rings in the fuel distributor, or the o-rings are too weak to hold unregulated pressure (related to what Randy described).

    Assuming all is proper - There should be zero fuel to the injectors until the air-flow meter plate plate is raised. The meter plate is that 80mm disk, under the rubber suction hood. *60mm disk for 1.8 engines.
    Last edited by epmedia; 05-12-2019 at 06:59 PM.
    Tbd

  4. #4
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    Thanks for the replies!

    I was worried the fuel pump might be a little much so picked up a fuel regulator with gauge that I'll go about installing before the fuel distributor and setting it the 60-74psi range to see if that helps.

    I am getting a strong constant flow out the return line but as I've never been around a properly working vehicle with this setup and it has sat for a time I'll double check that the return valve isnt gummed up like the meter piston was.

    I also have not looked at the metering plate yet but sounds like it may be a culprit.

  5. #5
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    Quote Originally Posted by CrunkGoat View Post
    Thanks for the replies!

    I was worried the fuel pump might be a little much so picked up a fuel regulator with gauge that I'll go about installing before the fuel distributor and setting it the 60-74psi range to see if that helps.

    I am getting a strong constant flow out the return line but as I've never been around a properly working vehicle with this setup and it has sat for a time I'll double check that the return valve isn't gummed up like the meter piston was.

    I also have not looked at the metering plate yet but sounds like it may be a culprit.
    Hi ...

    the fuel pressure regulator in the FD in a '79 model should be the later type with the "push" valve and is easily adjusted. Even the earliest type is adjustable but it is a lot more fiddly and the position of the shims is not obvious. I've managed to split up the "Fuel Supply and Adjustments" section out of the BMW 1977-79 North American 'Blue Book' manual into small enough chunks to be able to post it here for you.

    Using an external fuel pressure regulator may cause problems if it restricts the flow into the FD too much .. there should be a minimum of 750 cc of fuel out of the return line to the tank per 30 seconds with the fuel pump relay "jumpered".

    That you are getting "a strong constant flow out the return line" sounds like the fuel pressure regulator in the FD is probably not too much of a problem. All thought it probably does need all the internal o-rings replaced.

    The metering plate in the AFM does need to move freely and smoothly but iit is more likely to cause drivability issues like hesitation etc if it is operating enough to let the engine to start. The next question is ....
    How easily does it start ? Do you have to churn it for a while or does it start cleanly ?

    If it is starting cleanly ... it is possibly the Aux Air Slide/Valve (the one on the top of the cylinder head) or the Warm Up Regulator having problems during the warm up phase.
    Under a cold start ...
    The Thermo Time Switch controls the Cold Start Injector to add extra fuel to allow the cold engine to start.
    The WUR under cold conditions has also reduced the control pressure to allow extra fuel to the injectors.
    The AAV is opened enough to allow the right amount of extra air into the engine to allow all this extra fuel to burn properly.
    After engine start the AAV and the WUR should act together to reduce the amount of fuel going into the engine to normal running condition and at the same time the AAV should be closing to reduce the additional air into the engine so it all ends up at the right Air Fuel Ratio.
    Both the AAV and the WUR have electrical heating elements in them to do this. So try cleaning the plugs and sockets .. a bit of oxidation on the connections is never good.

    Also, check to see if the valve in the AAV moves. Before starting the engine ... take of one of the air hoses and note the position of the valve. When it shuts down after starting .. check it again to see if it has moved at all.

    The only way to check the WUR is to put a pressure gauge on it and watch to see if the control pressure starts to change after starting.

    These are the simplest things to check first .... unfortunately if it is none of these .. the 2.0 litre North American models have all that complicated vacuum controlled anti-pollution stuff on them. Looking at the diagram for it .. there is an addition vacuum controlled aux. air valve there too. Sorry, I don't have any idea how to check that stuff ... out here in the rest of the world we didn't have to worry about anti-pollution equipment for a few more years.

    Cheers
    Last edited by GDAus; 05-15-2019 at 04:43 AM. Reason: Reloading Attachments
    hmm .. Wonder what happens if I do this ...

  6. #6
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    To avoid possible confusion...
    The AASV (Aux Air SLIDE Valve) is 'metered air', meaning that the AASV does Not change the air-fuel ratio.. it just simulates your foot on the gas pedal while the engine is warming-up. The AASV takes a passage around the throttle plate in the throttle body, similar as the idle air screw's way of passage (also metered air).

    *The K-Jet 'Aux air SLIDE valve' is also referred as 'Additional/Aux air valve' in some litterateurs (adding to confusion even more).

    EDIT: lets refer this AAV as AASV "Aux/Additional Air SLIDE valve". Because the 2.0 has that big round thing that's also called an Aux air valve...

    I added the word SLIDE
    Last edited by epmedia; 05-15-2019 at 03:01 AM.
    Tbd

  7. #7
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    Quote Originally Posted by epmedia View Post
    To avoid possible confusion...
    The AAV (Aux Air Valve) is 'metered air', meaning that the AAV does Not change the air-fuel ratio.. it just simulates your foot on the gas pedal while the engine is warming-up. The AAV takes a passage around the throttle plate in the throttle body, similar as the idle air screw's way of passage (also metered air).

    *The K-Jet 'Aux air valve' is also referred as 'Additional air valve' in some litterateurs (adding to confusion even more).
    Hi Robert .... Thanks

    Yes .. I was struggling to try and explain all that. Trying to translate German technical terms gets a bit weird at times. that is probably where the overlap of terms has creep it.
    But somewhere amongst all the stuff I've collected on K-jet over the years .. there is a pretty big clear set of illustrations showing the vacuum systems on the NA 2 litre. I just have to find it and scan it. That should bring a bit more clarity to the situation.
    Last edited by GDAus; 05-15-2019 at 02:23 AM.
    hmm .. Wonder what happens if I do this ...

  8. #8
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    Looks like the attachments I added to my earlier post have just disappeared

    so I will try again
    hmm .. Wonder what happens if I do this ...

  9. #9
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    Quote Originally Posted by GDAus View Post
    Hi Robert .... Thanks

    Yes .. I was struggling to try and explain all that. Trying to translate German technical terms gets a bit weird at times. that is probably where the overlap of terms has creep it.
    But somewhere amongst all the stuff I've collected on K-jet over the years .. there is a pretty big clear set of illustrations showing the vacuum systems on the NA 2 litre. I just have to find it and scan it. That should bring a bit more clarity to the situation.
    The darn terminology. lol
    I did an edit to that post, because there's another 'Aux air valve' on the NA 2.0. I have to remind myself to include the word SLIDE, as you did.

    Here's a vacuum related pic from the Haynes, which does not show a cut-view of all the ports in the throttle body. Nor is the word SLIDE included to item #2. It also does not show 4th gear vacuum ignition timing advance components.

    click to enlarge
    Attachment 651724
    Last edited by epmedia; 05-15-2019 at 03:03 AM.
    Tbd

  10. #10
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    Quote Originally Posted by GDAus View Post
    Looks like the attachments I added to my earlier post have just disappeared

    so I will try again
    Those are Gold, I saved them. Great explanations on those big round air valves too (vacuum regulator & aux air valve).
    Last edited by epmedia; 05-15-2019 at 03:35 AM.
    Tbd

  11. #11
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    Quote Originally Posted by epmedia View Post
    Those are Gold, I saved them. Great explanations on those big round air valves too (vacuum regulator & aux air valve).
    looks like the forum is having a few gliches with attachments etc ..took me a while to get it to let me edit and reattach the files to my earlier post and now Roberts attachment is throwing up an error message

    But I have just scanned the other diagram I was looking for ... and I found a different reference to the electric Aux Air Valve calling it an Aux. Air Device

    Hopefully the attachment will stick this time
    Attached Files Attached Files
    hmm .. Wonder what happens if I do this ...

  12. #12
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    Thanks for the replies everyone! The attachments arent showing for me but im on my phone at work so I'll try when I get home on a computer.

    When the engine is cold it fires right up, no churning or on the starter for any excessive amount of time.

    Hooked up the pressure regulator last night, set it to the correct psi and still couldnt get the injectors to not spray when the fuel pump was given power. Checked the return line for any blockage and cleaned the pressure valve itself but didnt change anything.

    Pulled the plastic boot off the metering valve and it was fine, resting correctly and not binding in the slightest which leads me to believe the seals/o rings in the distributor must be bad. Upon closer inspection of the distributor itself it is leaking a bit of fuel from the base aswell.

    With that discovery we started checking over some of the other components and noticed the auxiliary air valve is stuck closed and the cold start injector intermittently seems to work now (was working when we first checked it so thought it was fine.) One crank itll spray the next it wont want to and so on.

    With these issues ontop of the distributor itself the owner of the car wants to give up on the injection and throw a carbureted intake on it to get it driving and eliminate the hassle (hes older and likes carburetors anyway.) If we go that route from the limited research I've done so far it seems any 2002 intake be it a 1.6 or 2.0 will bolt on but figured I'd double check here before ordering anything.

  13. #13
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    Quote Originally Posted by CrunkGoat View Post
    Thanks for the replies everyone! The attachments arent showing for me but im on my phone at work so I'll try when I get home on a computer.

    When the engine is cold it fires right up, no churning or on the starter for any excessive amount of time.

    Hooked up the pressure regulator last night, set it to the correct psi and still couldnt get the injectors to not spray when the fuel pump was given power. Checked the return line for any blockage and cleaned the pressure valve itself but didnt change anything.

    Pulled the plastic boot off the metering valve and it was fine, resting correctly and not binding in the slightest which leads me to believe the seals/o rings in the distributor must be bad. Upon closer inspection of the distributor itself it is leaking a bit of fuel from the base as well.

    With that discovery we started checking over some of the other components and noticed the auxiliary air valve is stuck closed and the cold start injector intermittently seems to work now (was working when we first checked it so thought it was fine.) One crank itll spray the next it wont want to and so on.

    With these issues ontop of the distributor itself the owner of the car wants to give up on the injection and throw a carbureted intake on it to get it driving and eliminate the hassle (hes older and likes carburetors anyway.) If we go that route from the limited research I've done so far it seems any 2002 intake be it a 1.6 or 2.0 will bolt on but figured I'd double check here before ordering anything.

    Ok .. the attachments I posted were PDF files so depending on your browser settings they were probably being downloaded rather than opened. Check you download folder.

    I must admit ... I thought you had gotten the injectors spraying with the engine stopped problem sorted out. ( I might have gotten this thread confused with another one in the forum )

    That they are still spraying and the new info that the electric AAV is stuck closed gives a different scenario on your problems.

    First off, I don't think you've mentioned anywhere if you have lifted the fuel distributor and made sure the metering plunger moving freely or not .... if is sticking and not dropping freely, then that needs to be fixed and could be your main problem.

    If it is okay then ...

    I think there is a strong possibility there is enough of a vacuum leak letting "unmetered" air into the engine side of the intake that the mixture has be richened to compensate .... and with the AAV stuck shut ..the mixture might have been richened more to get the engine to start from cold. That could have resulted in the metering plunger being high enough relative the the metering plate in the AFM, that it is letting fuel through to the injectors with the engine stopped.

    The 3 mm allen headed mixture screw has a very fine pitched thread on it and the adjustment range on a k-jet working properly is only a bit less than 1/2 a turn from too lean to run to too rich to run (from memory .. I haven't had to play with the mixture on mine for a long time)

    Also people get confused about which direction is which ....

    screwing it in (ie clockwise) richens the mixture
    screwing it out (anti-clockwise) leans the mixture.

    You can try screwing it out to see if the flow from the injectors lessens and hopefully stops.

    As to the stuck electric AAV... they do get gummed up with crud and it is possible to wash them out ... I start with kerosene and work upward to more aggressive solvents if that dosesn't work. There is an electrical heating element inside so dissolving the coating on that is the problem to be avoided.

    This is a link to a previous post about what's inside the AAV.

    https://www.bimmerforums.com/forum/s...9#post14617069

    Hope this might help

    Cheers
    hmm .. Wonder what happens if I do this ...

  14. #14
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    Ohh ... I should have added ..... if my scenario is right ...

    and you get the injectors to stop flowing with engine stopped .... it probably wont start unless the electric AAV is working and and the vacuum leak I'm suggesting if found and fixed.

    Cheers
    hmm .. Wonder what happens if I do this ...

  15. #15
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    The metering plate sounds like it’s sticky, I’ll tag along on that conclusion
    -John

  16. #16
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    Quote Originally Posted by CrunkGoat View Post
    Thanks for the replies everyone! The attachments arent showing for me but im on my phone at work so I'll try when I get home on a computer.

    When the engine is cold it fires right up, no churning or on the starter for any excessive amount of time.

    Hooked up the pressure regulator last night, set it to the correct psi and still couldnt get the injectors to not spray when the fuel pump was given power. Checked the return line for any blockage and cleaned the pressure valve itself but didnt change anything.

    Pulled the plastic boot off the metering valve and it was fine, resting correctly and not binding in the slightest which leads me to believe the seals/o rings in the distributor must be bad. Upon closer inspection of the distributor itself it is leaking a bit of fuel from the base aswell.

    With that discovery we started checking over some of the other components and noticed the auxiliary air valve is stuck closed and the cold start injector intermittently seems to work now (was working when we first checked it so thought it was fine.) One crank itll spray the next it wont want to and so on.

    With these issues ontop of the distributor itself the owner of the car wants to give up on the injection and throw a carbureted intake on it to get it driving and eliminate the hassle (hes older and likes carburetors anyway.) If we go that route from the limited research I've done so far it seems any 2002 intake be it a 1.6 or 2.0 will bolt on but figured I'd double check here before ordering anything.
    The cold start injector is on a heat/time circuit (via the heat time switch), so it may be working as designed.

    Because the fuel distributor is leaking (also probable bad o-rings causing leaks to injectors), the fuel distributor should be rebuilt (hopefully still rebuildable). Randy has a thread on the procedure and a source for rebuild kit.
    -----
    Is the warm-up regulator piped correctly? I ask about this wur because of how the other k-jet components have been modified... Fyi: if the wur has been set to very low fuel 'control' pressure (or non-existent control pressure), there won't be enough control pressure to force the fuel distributor's piston/plunger to proper rest position. Proper fuel 'control' pressure must be present when the fuel pumps are running, otherwise the fuel distributor's piston/plunger may just float to any position it wants.
    -----
    I the owner wants a carb setup, so be it. Just don't throw away the old k-jet components! please
    Last edited by epmedia; 05-16-2019 at 04:26 PM.
    Tbd

  17. #17
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    I've found this to very helpful in my efforts to do the same thing. When turning the fuel dist 6mm allen screw LEFT(ccw)=lean & RIGHT cw)=rich


    https://www.slideshare.net/guestceff...jection-manual

    Although a carb-if allowed in your area is cool too. If I could do a carb, I would go side drafts on a built motor. But we are under the control of big brother here in CA.
    Last edited by blacky77; 05-16-2019 at 05:02 PM.

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