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Vaccum Routing Help Desperately Needed!

Discussion in 'The Garage' started by K5er4Life, Dec 1, 2005.

  1. K5er4Life

    K5er4Life 1/2 ton status

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    Ok heres the deal, I picked up this 86 Crew Cab 4x4, with a 454/400/205. It has a little stumble when gas is given. If you give it either little or heavy gas it will stumble, a bit. Nevertheless, I went in to give the carb a tune up and I found that most of my vaccum lines are incorrectly routed. Could this be one of the causes of the stumble? What else is weird is the previous owner gave me a recent smog cert and the truck has passed emissions (except once in about 1994). Can you pass emissions test with the hoses incorrectly routed?

    Might as well throw in a few questions I was wondering. Has anyone ever seen these 4x4 Crew cabs in Cali (says on RPO sticker that its cali emissions equipped) with true dual exhaust and no cats. This truck has 80k original miles has been well taken care of and is almost unmolested. I say almost because the vaccum lines are the only thing that looks like it has been jacked with, I am baffeled with the vaccum hoses. Which gets me to my main question and most important. I can run the hoses fine and read the diagram but I am unsure of what some of these valves and hoses route to. Can someone please tell me what the hell the, "EFE/Dist TVS, EFE, Dist relay valve and TRC Valve" is. I did a search and didnt find much. I need to know anything else in the diagram that may be of help, as far as where these components are located, what they look like, or anything to help me identify them. This is my first dealings with the carb, and its a 86 (yay) so its gots lots 'o' vaccum lines everywhere. I took some pictures and I would greatly appreciate any help I can get, I have no idea where these hoses go until I can identify what all these valves and things are. Please someone help me out, any information given will be greatly appreciated.

    Also how do I know what ports to connect the hoses to on the carb? Are there markings on the carb that correspond to the letters on the diagram? ...J,B,L,T,H?

    And the service manual is of no help to help in identifying whats going on.
    Any advice as to where to start?

    Im terribly sorry for the 50 questions but this is a moment where aside from asking everyone here these questions I wont know who or where to go.

    Here some pictures...

    [​IMG]

    [​IMG]

    [​IMG]
     
  2. trailblazr81

    trailblazr81 1/2 ton status

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    Theres alot of wierd one way valves, and temperature activated vacuum vlaves. I just got rid of my 86 so cant help with pics. :doah: Those hoses are a pain. Your little sticker is in good shape. I used that and the bigger version in the manual.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Letters are actually on the carb, but hard to see with it installed in some of the locations.

    To me that vacuum diagram looks pretty simple...if the numbers of hoses going to the item correspond to what you see in the engine bay, that's what it is. :)

    For example, both TVS (thermal vacuum switch IIRC) in the diagram match up to what you took pictures of, as you annotated.

    Vacuum hoses hooked up wrong can definitely cuase problems...not all the ports get vacuum all the time, and some do. A hose hooked up wrong may cause a timed vacuum leak, or a constant one.
     
  4. K5er4Life

    K5er4Life 1/2 ton status

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    The diagram is easy to read, especially blown up. But I just am not sure that the EFE and the EGR Purge is what I labeled it in the picture.

    The whole thing is very screwy. If I labeled the pictures correctly than many of those hoses are incorrectly routed. Im going to dig in there this weekend and straighten it all out and I want to make sure I know what is what. Does anyone have a '86 454 cali controlled truck I could have pics of? Im not to worried about the sputter, I still am going to do cap/rotor, plugs, wires, timing, filters...etc Adjust the q-jet as needed. That should straighten anything wrong with it. I just have never had to mess with an 86 carb, I kind of like my TBI after seeing this mess of vaccum lines.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Just a thought, is your EFE TVS broken? It appears from the picture you have three lines, but there are four shown in the sticker...
     
  6. K5er4Life

    K5er4Life 1/2 ton status

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    Ok I think Im getting it figured out, the line is there. It looks broken because you cannot see the fourth line behind it. So I think I am correct in labeling pictures. But the only thing I dont see is that big valve that that I wrote in yellow, "whats this big valve?" I dont see it in the diagram or know if it is even suppossed to be in the system. Do you recognize that valve? Could it be the TRC valve?
     
  7. 90blzr

    90blzr 1/2 ton status

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    :haha:
    Just because you got a certificate saying it passed emissions...doesnt mean it
    'passed' emissions :wink1: But it IS good enough to get registration etc, for the next two years :D
     
  8. K5er4Life

    K5er4Life 1/2 ton status

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    The thing is I have smog certifiates from a few different places, all through different years performed by different smog techs showing that it passed. Also I looked on the cali dmv website which tells me when and where the cert was issued, and carfax confirmed this. Thats also why I am a little baffeled by it being able to pass. The po gave me alot of reciepts that show everything from oil, trans, radiator fluid changes. To when he had the brakes serviced. All the regular maintenance, the po didnt do any work on his vehicles, he took them in. The only way I can imagine the vaccum lines getting screwy was in around 2000 I have a receipt for servicing of the intake gaskets. (Im sure they were leaking a bit or something) Everything adds up in the truck, as far as the odometer reading, smog certs, services, everything.

    BTW...My blazer seems to have no problem "passing" smog every other year too. :wink1:

    Heres a pic of my blazer.

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  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Pull a vacuum line off of either side and see if it's a check valve. It could be something as simple as an inline filter as well, like the one for the brake booster. Not part of smog, so not on the chart? Just a WAG.
     
  10. K5er4Life

    K5er4Life 1/2 ton status

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    Thanks for the help guys. Im am going to digg into to this thing right now, so Ill let you know how it turns out.
     

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