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Air Horn Intake Control Box

Discussion in 'Bay Tech Clinic' started by onetrackwonder, Jul 11, 2019.

  1. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Hey guys I'm after a bit of advice, yesterday I got a call from a mate who owns a Kombi in Tilba, it is a 1.8L and he said that it has a bad fuel smell and should I still be driving it, he had just picked it up from the mechanics after a few months off the road getting the auto box repaired, I said stay there I will be straight over, so I grabbed my spares package out of the Kombi and went over, both fuel hoses from the carbs too the t piece were pissing fuel, somehow they had stretched the fuel lines around the front of the air filter and not running along the fuel tank cover, anyway I fixed it all up and also removed the fuel filter which was sitting over the top of a plug lead that was also off the plug and I then mounted it under the chassis and out of the engine bay
    I have only ever had aftermarket carbs for the last 30 years and can't remember how all the standard air filter system goes together, but one thing that I noticed was a spring clip laying on top of the drivers side tinware, it has two small holes in it and while I looked more I discovered these two nipples poking out the bottom of the air horn, hope thats the correct term and it is loose and easily pushed up into the body of the filter system, so its obvious to me that the clip somehow holds the two nipple control box somehow, anyone know how
    [​IMG]
    I have found this, top right corner the red and green or is it yellow hose coming from the underside of the air horn, oohs like the clip that I found underneath but I can't see clear enough
    [​IMG]
    These two nipples on the mates bus also don't have any hoses on them so I have asked him to bring it over when he gets a chance so I can look further, what I have found is that one line runs to the brake booster T at the carbie and I'm guessing if that isn't connected it won't help with the idle, and it isn't idling that smooth, the other goes to this bit which I'm not sure what it is or does, air inlet ?
    [​IMG]
    any advice will be much appreciated,
    Tomorrow morning I am fitting an air flow meter to another old mates T3 Ute that I was lucky to source through one of our members here, and my poor old girl still sits broken in the shed due to not having time, ha,got to love the Kombi life, cheers Greg
     
  2. cbus

    cbus Well-Known Member

    Messages:
    11,750
    Location:
    sunshine coast
    Certainly no lack of retards posing as mechanics.:eek:
    Good move to tell him not to drive it.
    Sounds like a dodged bullet.

    You have it pretty much sorted.
    Vac tee to one pipe on the snout and the other pipe hose to the air intake indicated in last photo.
    If it's working it changes air for engine from snout that often has a 60mm cardboard hose feeding from near starter battery to the intake behind the filter box.
    Maybe vice versa?
    But warm and then cooler air intakes.

    And , yep.
    Any vac leak will cause rough idle.
    The classic after a backfire is to check the rubber elbows on the vac line takeoffs on the inlet manifolds that connect to the brake vac lines.
     
  3. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,523
    Location:
    Avalon Beach NSW
    A fair bit missing/ disconnected there....
    The fuel vapour reticulation system has quite a few connections that can, potentially fail.
    Prime cause of fuel smell is leaking hose connections to the fuel pump....you’ll need to get under the bus and trace back from the fuel tank if running a mechanical pump....it’ll be near the driver side rear wheel arch.
    Next most common failure is the T-piece that is up on the engine bay roof.....often perished and ignored.
    Both easy to fix and with cheap and readily available parts....
    Looks like the warm air flap is disconnected....it branches off the vacuum line T piece.
    Other bit of advice I’d give is to get that fuel filter OUT of the engine bay........
    Good luck .....Now go work on yer own bus !!!
    Cheers,
    Mark
     
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  4. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Thanks cbus, that 60mm hose was laying on the tinware, it went into the hole under the fuel filler hose and had a plastic funnel taped to it, I was laughing as I said what the f is that
     
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  5. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Mark the T piece was another thing I need to fix for him but its not perished, just more bits missing, I take the pics when doing stuff to help me remember, must be getting old ha.

    [​IMG]

    Where does this T take the vacuums from on the inlet system, I haven't been able to find it yet
    I did move the filter out of the engine bay when I made good the fuel lines

    Katherine and I are currently nearing the end of our home build, all works being done by us and hopefully another couple of months and we should be close so I haven't had much time to give the Kombi its much needed love, the distractions helping to fix other Kombi's around here helps to give me a much needed mental break, thanks for the help, cheers Greg
     
    Last edited: Jul 11, 2019
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  6. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,523
    Location:
    Avalon Beach NSW
    Will check mine tomorrow.....;)
    Someone else will know, hopefully.
    It’s not part of the vacuum line, rather, it reticulates the fuel vapours......should be a closed system via the fuel tank.
    I’ve learned to take pictures as I dismantle......has saved heaps of time !
    Cheers,
    Mark
     
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  7. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Just thought that perhaps it goes to the charcoal filter,?
     
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  8. cbus

    cbus Well-Known Member

    Messages:
    11,750
    Location:
    sunshine coast
    Yeah.
    I would have been adding a few derogatory comments about the architect of the device as well :D

    Maybe it was his way of capturing spilled fuel from the stuffed elbow at the filler ??:rolleyes:
     
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  9. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Will get a photo of the setup next time I work on it, :)
     
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  10. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,818
    Location:
    Penna, Hobart
    It goes from the t piece to the top of the air filter, but is there is a charcoal canister it may go through that firs. All the ones I have had go into the filter, and are predominantly 1974-75 models which never had the canister. It has a fitting which looks similar to the rubber boot for the coil lead.

    The big pic further up look different to most type 4 setups too. The left hand nipple on the air horn goes to a nipple under the air filter coming off the link pipe between the two manifolds. When the carbs are set up correctly you should be able to disconnect it from the air horn end and by putting your finger on and off you should notice almost no difference in revs. Increase in revs is too rich and decrease is too lean.

    Below is the diagram for the venting system showing the connections.



    [​IMG]
    go to Ratwell.com and there is more info (although with an American bent) than you will ever need.


    Adrian
     
    Last edited: Jul 12, 2019
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  11. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Thanks Adrian, I can't remember seeing the charcoal canister but at the moment I wasn't really looking for one either, I have seen that pic above many times as before the last bus top I changed all of those little bits of fuel line in the breather system as our bus developed a bad fuel smell, the bit #24 had actually slipped off causing the smell, this bus that I'm working on is a 74 and I wasn't sure what that #28 connected too so thanks for that, I know the Ratwell page well, all the pics above that I posted came from that site, amazing effort for someone to assemble all of that information for future generations of Kombi owners to have access too, cheers and thanks again, Greg
     
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  12. Grantus

    Grantus Well-Known Member

    Messages:
    15,735
    Location:
    Southern ACT
    I’ve followed this whole thread, but sadly have nothing useful or knowledgeable to contribute.....:(

    Yet I’d love to know more, or see some pics of the T3 Ute. :)
     
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  13. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Hey Grant thanks for the interest, also congratulations on your second place at the nationals, we were not able to make it there this year due to the house build and wanting it finished sooner rather than later, one day you may be able to help, especially with the T3, it came out today so I could change out the AFM and when it pulled up it was pissing water out from underneath, so got it in the shed and sorted the Air Flow Meter first which was pretty easy and then had a look at the water leak which turned out to be the coolant reservoir, it was leaking from the engine side of the seam around the middle of the bottle, further prodding I realised that it had some sort of filler over the leak which wasn't holding, so a quick search I found a new one and ordered it, while I was working I thought I should take a photo but the phone was in the house and I didn't think about it again, it is a white 2.1 litre single cab and look's pretty much like the one that you dragged home the other day only with more dents, I have yet to see any rust, when I first started working on it, it didn't look too bad, as he gets older he backs into and hits more things at his home so it is starting to get a bit knocked around but I think that it is still way cool, from the last time that I worked on it he has gotten very dodgy on his legs so I doubt that he will be driving for much longer unless the doctors can produce some magic, when I get the coolant bottle I will get a few photo's just for you, cheers Greg
     
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  14. Grantus

    Grantus Well-Known Member

    Messages:
    15,735
    Location:
    Southern ACT
    Thanks Greg,

    And the Tilba area is a very special place to live..... one of my favourite South Coast places to stop by for a coffee, and some cheese shopping, whenever I pass by. :)
     
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  15. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Thanks Grant, yes its a very special place, especially to us, make sure that you let us know next time you pass by and we will catch up, cheers Greg
     
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  16. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,818
    Location:
    Penna, Hobart
    Looks like you re all over it. Good luck,

    Adrian
     
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  17. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    1,017
    Location:
    Bateau Bay, NSW
    You’re mate is very lucky he’s got you to help him avoid catastrophe!

    “Air horn” may not be absolutely correct, but the most common name I’ve seen is “pizza slice” and I’m thinking “air horn” is probably a little more technically correct :-D

    The “Warm Air Thermostat” that is mounted in the Air Horn is held in place by a Spring Clip. The Spring Clip has an angled prong each side of each of the two Warm Air Thermostat pipe connections. The angle of the prongs makes it easy to slide the clip on the pipe connections, but hard to slide it off. The ends of the Spring Clip also have an angled prong hanging out that retains the hose on the hose connection. The Spring Clip is kind of a U shape if it’s correct.

    When working properly, the Warm Air Thermostat controls the amount of vacuum that goes to the Warm Air Flap Diaphragm depending on the temperature of the air inside the Air Horn. This means the air entering the air filter should be at least 21 deg C. When the air temperature exceeds 21 deg C, the flap moves across so that only cold air enters the air filter.

    That’s the Warm Air Flap Diaphragm. It controls a flap inside the air intake that controls how much cold or hot air comes into the air filter housing. Combined with the Warm Air Thermostat, the temperature entering the Air Filter should be at least 21 deg C. This helps to atomise the fuel and means your engine runs much better with better fuel economy.

    That’s no good mate. Perhaps I’ll have to come visit the ridge and we can have some beers and have a tinker.
     
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  18. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    1,017
    Location:
    Bateau Bay, NSW
    Here’s a picture of the Spring Clip and Warm Air Intake Thermostat (partially disassembled).

    23AFEED7-5E4B-47D2-BDB4-9643F11ABBBB.jpeg
     
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  19. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    1,017
    Location:
    Bateau Bay, NSW
    Here’s the setup with the carbon canister. (15) appears to be where you have a missing hose.

    On mine, the hose (12) comes off a hose connection on the side of the fan housing and hose (13) goes onto a one way valve that’s pushed into the top of the air cleaner housing. The carbon canister (1) is fastened to the roof of the engine bay.

    F1DDDAB8-6A96-4481-9D4F-D373C976276C.jpeg
     
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  20. onetrackwonder

    onetrackwonder Active Member

    Messages:
    110
    Location:
    Central Tilba, NSW
    Thanks Chris any time you guys want to come down to the Ridge for some R and R you would be more than welcome, had to go into Tilba today to get fuel for the bobcat and had a quick look at the kombi as it was parked in the main drag, there is no carbon canister and the warm air intake thermostat was now gone so I expect that it is in the system somewhere as the clip is not holding it there, just thought that I hope it won't fit down the throat of the carbie, must go into town again and get it out tomorrow, yes that was the clip that I found on the tinware, do you happen to have a photo of that clip installed as I can't get my head around how it holds the warm air intake thermostat in place , have to thank you guys again as I am getting my head around most of this, cheers Greg
     
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