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Thread: Vacuum issues

  1. #1

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    Vacuum issues

    At idle i get 14 in.... but driving down the road i get 5in...

    New cat..new muffler.. cleaned egr.. new vacuum hoses.

    Last tank of fuel was 11.7 mpg..

    2.4 auto

  2. #2

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    Try adjusting your timing to raise your idle vacuum to about 20. If you can't get it to that reading, you either have a leak around the manifold somewhere or your rings are toast, but if you were getting normal readings prior to your exhaust being repaired, a restriction has been introduced somewhere.
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  3. #3

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    I took the lines off the charcoal canister and plugged the lines, pulled the EGR off and verified it was clean, and put gasket sealer on the gasket ( as I had it off last year to clean and wanted to make sure it sealed)...

    Vaccum is up to 17 in at idle and up to 6 in at 60 mph in overdrive... but I can get 8in in 3rd gear at 60 and 3100rpm...

    GRRR... hard to believe that at less than 2000 RPM I can`t get any vaccum.. which I suppose is because I`m crazy underpowered and need more throttle to maintain speed...

  4. #4

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    To be clear.. this is manifold vacuum I'm reading.. not ported vacuum

  5. #5

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    does the needle fluctuate? Or is it a steady vacuum signal. A friend of mine had a relatively new car, allegedly caused by a tank of bad gas, it melted the guts in the cat. It was down on power until it wouldn't start or run. Try unbolting the the exhaust and start it up and see what the vacuum is. New parts are just as suspect to me as old parts. I once got a used cat that was cleaned up really well and taped back up in the box. Didn't realize it until it was half installed and there was a stripped stud sticking out of the flange.

  6. #6

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    Unplugged the egr and capped off all three ports on the throttle body and now im up to 9 in in 4th and 11 cruising at 3000 in 3rd..

    The cat is new.. and the truck pulls to 5000k no problem unlike with the old pump it wouldnt pull to 3800..

  7. #7

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    After driving almost 1000km.. i can now cruise at 10 in.. and get 17 in at idle...
    Could it be sitting has done this?

  8. #8

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    Rings not sealing properly/coked up and then finally getting some oil - maybe?
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  9. #9

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    Maybe I should run sea foam through this engine

  10. #10

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    That 'might' clean up the combustion chambers but it won't do much else (no harm in testing it out). Maybe try an engine flush as spent oil laminating everything inside an engine doesn't help.
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  11. #11

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    What do you have for vacuum when engine braking? Your reading of 17 at idle sounds weak to me, unless you have a lumpy cam.

  12. #12

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    Descelerating i get 24in vacuum.
    Engine is bone stock

  13. #13

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    That doesn't sound bad to me. Others on here would probably know better than myself. I would suspect it has to do with ignition or valve timing. An easy thing to check is that the timing mark on the harmonic balancer hasn't moved. Find TDC by putting a small stick in the #1 spark plug hole, rotate the engine slowly by hand until the stick is at it's highest point, and verify that you are close to the TDC mark.

  14. #14

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    So i ran seafoam through the engine using a vacuum line...
    I smoked and then i let it sit for an hour.

    When i started it up after the hour.. i couldnt see my hour or my 2 neighbours house and it smoked for a good 15 min while i ran the engine at 3000rpm..

    Wow...is that normal?

  15. #15

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    Yes, that stuff is great if you ever want to make a smoke screen - just run a vac line to the manifold and have the other end attached to the seafoam in the cab and give it a blast. I am on the fence with this stuff. I think a hand trigger spray bottle with clean water would do the same job in the combustion chambers minus the white cloud (and it's free). Water is boiled straight in the chambers, the steam penetrates the carbon build up and then it swells and burns off. You can hear it crackle through the exhaust system...
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  16. #16

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    Yup, water works great! No theatrics, but you don't have to spend 10 bucks either.

  17. #17

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    Running a bit better.. pulls great to 4100... they slowly creeps to 5000rpm. Could be valvetrain limits or just the way the stock cam is. I have no idea. It should have TONS of fuel to use with that new pump

    I'm running the truck this Saturday at a Mopar Show and Drag Race.. I hope to run at least 19 seconds..

    I'm gonna set the kick down to shift automatically at 4100 then RPM out the back in 3rd gear..

  18. #18

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    Try retuning the ignition (this will work as long as your O2 sensor is working) -

    http://www.mightyram50.net/vbulletin...ll=1#post59777

    ...should dig up some hidden HP
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  19. #19

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    Well.. she is slow.. nest pass at the track was 20.33 at 62...
    That works out to 47.5 hp to the rear wheels..

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