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Thread: Well the poor old 535 and her

  1. #1
    Join Date
    Jan 2004
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    4,150

    Default Well the poor old 535 and her

    new fuel pump that i had gotten off of ebay weren't quite right....
    Since i installed it ,the tank,filter and injectors, I was having the usual hot start problem with 3 trys to start it when hot soaked...

    I checked the fuel pump pressure and it was good but instantly went to zero,when shut off, I thought to myself it could be the fuel pump check valve, or the fuel pressure regulator letting fuel drain past, or a number of leaking injectors. So i deadheaded the pump by pinching off the return line from the regulator and briefly cranked the engine, gauge shot up above 70 and then when i stopped cranking instantly went to zero
    That pretty much confirmed it. So i installed the bmw retrofit check valve kit 16 14 9 068 988..... pretty cheap from Patrick at bma, less than 10 bucks. Nice kit ,comes with checkvalve, fuel line, hose insulator, hose crimp clamps and plastic nut covers to get rid of sharp edges on the pump cover.
    Attached Images Attached Images  
    Last edited by Bill R.; 02-08-2009 at 05:42 PM.


  2. #2
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    Jan 2004
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    4,150

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    After running it for a good while getting it good and hot, shut engine down and waited 45 minutes with the pressure gauge hooked up... Pressure guage only dropped to here




    Quote Originally Posted by Bill R. View Post
    new fuel pump that i had gotten off of ebay weren't quite right....
    Since it installed it ,the tank,filter and injectors, I was having the usual hot start problem with 3 trys to start it when hot soaked...

    I checked the fuel pump pressure and it was good but instantly went to zero,when shut off, I thought to myself it could be the fuel pump check valve, or the fuel pressure regulator letting fuel drain past, or a number of leaking injectors. So i deadheaded the pump by pinching off the return line from the regulator and briefly cranked the engine, gauge shot up above 70 and then when i stopped cranking instantly went to zero
    That pretty much confirmed it. So i installed the bmw retrofit check valve kit 16 14 9 068 988..... pretty cheap from Patrick at bma, less than 10 bucks. Nice kit ,comes with checkvalve, fuel line, hose insulator, hose crimp clamps and plastic nut covers to get rid of sharp edges on the pump cover.
    Attached Images Attached Images  


  3. #3
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,249

    Default

    Thanks a lot Bill. Nice pics, I needed that too for my website and there are offten question about that, and will borough that and mention your name, if you agree.

    My collection so far
    http://i230.photobucket.com/albums/e...t/IMGA0609.jpg
    here non-BMW http://members.cox.net/zmuff/crop%20...lve%20done.jpg

    installation pics E30
    http://www.bimmerboard.com/forums/posts/496880/

    When yo talk to Patrick at BMA, tell him the pic does not work.

    Used with the search there with the part number, 16149068988 CHECK VALVE KIT
    Last edited by shogun; 06-25-2016 at 07:36 AM.

  4. #4
    Join Date
    Apr 2005
    Location
    Canada
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    222

    Default

    Quote Originally Posted by Bill R. View Post
    ....
    Since i installed it ,the tank,filter and injectors, I was having the usual hot start problem with 3 trys to start it when hot soaked... .
    Q1) Why a bad gas check valve is this hard starting problem source only when engine hot, not also when it's cold ?

    Q2) Does this check valve kit add a second check valve in serie with the pump, why not just replace the existing one ?

    Glad to see that it solve the problem easily and cheap.

  5. #5
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    Jan 2004
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    Quote Originally Posted by Claude View Post
    Q1) Why a bad gas check valve is this hard starting problem source only when engine hot, not also when it's cold ?

    Q2) Does this check valve kit add a second check valve in serie with the pump, why not just replace the existing one ?

    Glad to see that it solve the problem easily and cheap.
    When hot, the fuel will boil in the fuel rail by the injectors creating an air lock or vapor lock when you have it under pressure it raises the boiling point and also gives it no place to go. On a cold start the fuel is denser and the pump fairly rapidly gets to the injectors , but it still starts faster with a good check valve.

    Q2, it takes less than 5 minutes to install the check valve start to finish and doesn't hurt to have 2 in series, its a lot more trouble to pull the fuel pump out of the tank to replace the check valve. This was a cheap 88.00 ebay pump so for less than 10 more it works fine now.


  6. #6
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    Apr 2005
    Location
    Canada
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    Quote Originally Posted by Bill R. View Post
    When hot, the fuel will boil in the fuel rail by the injectors creating an air lock or vapor lock when you have it under pressure it raises the boiling point and also gives it no place to go. On a cold start the fuel is denser and the pump fairly rapidly gets to the injectors , but it still starts faster with a good check valve.

    Q2, it takes less than 5 minutes to install the check valve start to finish and doesn't hurt to have 2 in series, its a lot more trouble to pull the fuel pump out of the tank to replace the check valve. This was a cheap 88.00 ebay pump so for less than 10 more it works fine now.
    Thanks for your explanations Bill. Another one: When we purchase a new full pump does it come equip with a new check valve on it or do we have to order it separately ?

  7. #7
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    Jan 2004
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    Quote Originally Posted by Claude View Post
    Thanks for your explanations Bill. Another one: When we purchase a new full pump does it come equip with a new check valve on it or do we have to order it separately ?
    The check valve is condsidered an integral part of the pump, it comes with it built in more or less.


  8. #8
    Join Date
    Jul 2006
    Location
    Ottawa, Ontario, Canada
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    156

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    Bill R,

    How exactly did you hook up the check valve. From the picture I can't see now you tapped into the send line?

  9. #9
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    Quote Originally Posted by angusbn View Post
    Bill R,

    How exactly did you hook up the check valve. From the picture I can't see now you tapped into the send line?
    I added arrows and text to the picture , it should be obvious now.


  10. #10
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    Jan 2004
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    Erich, next time i order from bma i can check for you if you want. How many would you like? I can check my local dealer also, I have to pick up some e46 parts from them in the next couple of days anyway.


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