740 Throttle body

Discussion in 'Volvo 740' started by Bill, Oct 17, 2003.

  1. Bill

    Bill Guest

    As part of my on-going "sorting" of my 1989 740GL the next job is to clean
    the throttle body....or is it?

    I can't find it!

    I have put some pictures of the engine (B230E, CI Fuel injection) at:

    http://www.worldisround.com/articles/23352/index.html

    Can anyone point me in the right direction.

    Thanks

    Bill
     
    Bill, Oct 17, 2003
    #1
  2. From a point at sea, to the circles of your mind, this is Bill:

    It's under the inlet manifold - that big aluminium thing with legs on
    top of the engine. There's a black rubber boot that connects the air
    flow meter to the throttle body. If you operate the accellerator cam
    (the accellerator cable attaches to it) you will see a linkage moving
    - follow this linkage to the throttle body.


    --

    Stewart Hargrave

    A lot faster than public transport


    For email, replace 'SpamOnlyToHere' with my name
     
    Stewart Hargrave, Oct 17, 2003
    #2
  3. Bill

    Bill Guest

    Thanks Stewart, I will have another look later. I got the Haynes manual you
    recommended (the black covered one). I see why it is preferred over the new
    one, certainly more comprehensive, except for the throttle body!

    Bill
     
    Bill, Oct 17, 2003
    #3
  4. Bill

    Bill Guest

    I have just been out and had another look. As you say there is the rubber
    boot. The throttle body is the bit between the boot and the inlet manifold,
    correct? To remove it is it just a simple operation of undoing the worm
    drive clip that holds the boot to the TB, removing everything connected to
    it, then undoing the nuts. There is a microswitch attached which is
    operated by the linkage, but looking at my picture again I don't think it is
    attached to the TB, just blocks easy access to the nut. Is the throttle
    position switch inside the TB, or does it remain in the inlet tract when the
    TB is removed.

    Apologies for so many questions, but I would rather ask before I start than
    get stuck halfway through the job!

    Thanks again

    Bill
     
    Bill, Oct 17, 2003
    #4
  5. From a point at sea, to the circles of your mind, this is Bill:
    Never needed to get that far myself, but it sounds about right. I
    would anticipate that there would be a gasket or O-ring between it and
    the manifold.
    My car is a bit earlier than yours ('87) and doesn't have a TPS, so I
    don't know the answer to that. AIUI, unless you have a catalyst, K-Jet
    doesn't need one. Thinking about it, mine too has a microswitch that
    I've puzzled over. It's not connected to anything, so my guess is that
    it is there for models that have some sort of constant idle control -
    it seems it would only sense when the throttle is fully closed - and
    is redundent on mine.

    TBH, unless you have a problem specifically related to the throttle
    valve I wouldn't be going to the trouble of removing it. Clean and
    lubricate the outside linkage mechanism, make sure this is working
    smoothly, and opening and closing properly. There is much less inside
    the TB than outside it (only the butterfly valve of the throttle).
    It's not nearly as complicated as a carburetter.


    --

    Stewart Hargrave

    A lot faster than public transport


    For email, replace 'SpamOnlyToHere' with my name
     
    Stewart Hargrave, Oct 17, 2003
    #5
  6. Bill

    James Sweet Guest

    Weird, that's the first time I've seen that setup, looks almost like an '81
    or earlier 240 except for the distributor on the back of the head. Was KJet
    cheaper than LH Jet or something?
     
    James Sweet, Oct 18, 2003
    #6
  7. Bill

    James Sweet Guest



    When I did this on a '79 240 I found it was easier to remove the intake
    manifold, though you should replace the gasket if you do that. There's also
    a gasket between the TB and the manifold that should probably be replaced
    but if you're careful you can reuse it if you have to.
     
    James Sweet, Oct 18, 2003
    #7
  8. Bill

    G Klein Guest

    On your Fuel system there is no throttle body as in a
    LH car what would have to be done is either remove the
    rubber boot that goes in between the Intake Manifold &
    the throttle unit or as others have suggested remove
    the intake manifold
     
    G Klein, Oct 18, 2003
    #8
  9. Bill

    James Sweet Guest

    Sure there is, in fact it's the exact same throttle body LH Jet uses, it's
    just mounted on a different manifold.
     
    James Sweet, Oct 18, 2003
    #9
  10. Bill

    Mike F Guest

    K-Jet is cheaper, and simpler, so there's less to go wrong. However
    it's not as precise, so emissions are higher. It was always used on the
    normally aspirated 8 valve "E" engines.
     
    Mike F, Oct 20, 2003
    #10
  11. Bill

    James Sweet Guest

    Perhaps less to go wrong, but what can go wrong seems to do so more often. I
    know some have had great luck with KJet but for me it's been nothing but
    hassle, LH Jet always seems to run perfectly and when it doesn't the problem
    is generally pretty obvious and easily diagnosed.
     
    James Sweet, Oct 21, 2003
    #11
  12. Bill

    Mike F Guest

    Sitting for a long time without use is hard on K-Jet, because of the
    accurately machined steel parts in the fuel distributor. Other than
    that the only part that really fails is the warmup regulator, and
    sometimes injectors. It's biggest flaw is how it reacts to vacuum leaks
    though.
     
    Mike F, Oct 21, 2003
    #12
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