Vacuum Leak

Discussion in 'SN95 4.6L Mustang Tech' started by UK_Wildcat_Fan, Aug 31, 2014.


  1. UK_Wildcat_Fan

    UK_Wildcat_Fan New Member

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    Hi
    I have a 2004 GT. I have a vacuum leak. I have sprayed carb cleaner to check where the leak may be. So far I have found a leak in the IAC valve hose. I have looked all over the internet for a hose to replace it with. Auto Zone and NAPA say that its a dealer part only. I was wondering if anyone may know where I can get a IAC valve hose to replace mine. I'm trying to stay away from my dealer because not trusting them. Thanks for any help.
     
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  2. TeamCaffeineGT

    TeamCaffeineGT Member

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    UK_Wildcat_Fan,
    You should be able to source a chunk of heater hose or large vaccum hose at your local hardware store. Not sure what leads you to believe you have a vaccum leak, high idle perhaps? If this is the case, the repairing the hose from the air cleaner to the IAC is not the solution. The IAC is bolted to the upper plenum and has a gasket between the two pieces. The unit us also electronically controlled, not vaccum controlled. The only vaccum lines o believe the car has are to the EGR, fuel pressure switch, the interior climate controls and a couple for the evap system. They all feed off of the main vaccum from the upper plenum. Hope that helps!

    Best of luck!
     
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  3. 1987stangman

    1987stangman Member

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    He would have an unmetered air leak that could cause a lean condition.
    If you have an advanced auto parts store where you live they have a 'help' section that has those odd ball pieces. You should be able to find something that works well. Same goes for the hose that comes off the valve cover on the drivers side. I sourced a new on from them.
     
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  4. TeamCaffeineGT

    TeamCaffeineGT Member

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    UK_Wildcat_Fan,
    We need more specifics on the symptoms you are experiencing that lead you to believe you have a vaccum leak!
     
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  5. UK_Wildcat_Fan

    UK_Wildcat_Fan New Member

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    Thanks for the replys I am getting a P0174 I know that is lean bank on the drivers side. So I was starting with simple things first. When the car is running the idle is rough like its going to die. I can hear air being sucked in or being blowed out. If knew how to post a video of it I would. Anyway I sprayed carb cleaner on hoses that would effect it on the drivers side. I was wrong when I said IAC valve hose. Its the hose under the IAC valve hose. When I sprayed carb cleaner on that rubber elbow the engine would surge like I would be pressing the gas pedal every time I sprayed that elbow. This rubber elbow connects to the trottle body. Hope this helps, and again thanks. I'm laid off right now and don't have the extra money to be throwing parts at it.
     
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  6. 1987stangman

    1987stangman Member

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    Are you only getting the P0174 code? A vac leak would generally cause a lean condition on both banks but if it's the hose that runs from the PCV valve to the intake that could Def cause a single bank lean condition. The computer tries to compensate by adding fuel. When it gets to a point it has added to much a code is thrown. But it sounds like you have found the issue using the carb spray. You need to get a scan tool capable of supplying live data and give us more info like long term fuel trim data for each bank. I would get your vac lines you think have an issue with fixed and reset the codes first to see if that helps. You can disconnect the battery for a few min to completely reset KAM. If you can get a scan tool and give us some more info we can give you more specific help.
     
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  7. TeamCaffeineGT

    TeamCaffeineGT Member

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    That rubber elbow is the main vacuum for EVAP and the fuel pressure switch. I believe the EGR runs off of the back of the plenum. Like 1987stangman stated above, fix the leak and then disconnect the negative battery terminal to clear the ECM DTCs. You should be able to get that elbow at the dealership, or a lot of the times the parts store will carry assortments of vacuum hose related parts.

    Good Luck!
     
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