Help with vacuum gauge readings. Extremely low. Possible leak?

Discussion in '94-95 5.0 - Specific' started by Kylebach14, Apr 18, 2014.

  1. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    Just finished up a HCI swap and noticed that it has no power so I did a vacuum test and it flickers between 7 and 10 which is extremely low. I heard that if you have a cam it will flicker. I just want to know why it flickers and why its so low. When I accelerate it climbs up and gets more steady. I've sprayed all over and cant find a vac leak. I'm thinking it could possibly be a lower intake leak. Would it be a waste of time to re do my lower intake gasket? Thanks

    Heres a vid of the gauge:
    https://www.youtube.com/watch?v=NbfrovhFpQ0
     
  2. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    Cam? Is your timing ok. How is the fuel pressure. . Use some permatex tack gasket sealer

    Enviado usando mi SHP-L710 usando TapaTalk
     
  3. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    TFS 1 Camand timing is set at 10 degrees with spout out. The engine was cold when I tested it if that has anything to do with it
     
  4. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    [​IMG]

    Enviado usando mi SHP-L710 usando TapaTalk
     
  5. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    Tfs1 I want to say I had 17 inches vacuum. When I did mine I unplugged every vac line plugged them. then plugged in one at a time. . It can also be the tune. Injectors size?

    Enviado usando mi SHP-L710 usando TapaTalk
     
  6. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    Stock 19 pound injectors,TB, MAF.
    I heard it may be a possible valve seal issue but I dont think thats the issue. I'm hoping its just the lower intake
     
  7. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    It's possible or a simple vac leak. Did you check the hoses going to the evap. Smog & egr hard plastic lines

    Enviado usando mi SHP-L710 usando TapaTalk
     
  8. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    I deleted the smog and taped off the smog lines. I also deleted my AC and left the two pipes in the firewall open. would this affect anything?
     
  9. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    Did you delete the egr?

    Enviado usando mi SHP-L710 usando TapaTalk
     
  10. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    Yes I deleted the EGR
     
  11. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    Then remove all those colored hard lines

    Enviado usando mi SHP-L710 usando TapaTalk
     
  12. toyman

    toyman Active Member

    Messages:
    874
    Likes Received:
    9
    Joined:
    Aug 25, 2008
    There are a lot of hidden vacuum lines. You could pay to have a smoke test done or you could fab a fitting to attach to the TB with a tire valve that will allow you to pressurize the system using a bicycle pump. If there isn't a leak the pressure will hold and if it's leaking you should be able to hear the hiss of the escaping air.
     
  13. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    Never thought about that

    Enviado usando mi SHP-L710 usando TapaTalk
     
  14. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    I'm not sure what is going on. I cant find a leak at all on this, yet it has low vacuum. Someone on another forum said maybe my rockers are too tight.
     
  15. Mack

    Mack Well-Known Member

    Messages:
    1,231
    Likes Received:
    52
    Joined:
    Apr 27, 2010
    Location:
    Rotterdam, Netherlands, Netherlands
    I have the exact same issue with my car. Last week I had a smoke test done and they found no leak. Can't figure out what is wrong either.
     
  16. rz5.0

    rz5.0 Legend

    Messages:
    5,853
    Likes Received:
    130
    Joined:
    Mar 26, 2010
    Location:
    Great state of TEXAS
    It's possible if your rockets are to tight then your valves are not closing all the way. . Also is your car tune?..

    Enviado usando mi SHP-L710 usando TapaTalk
     
  17. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    No it doesnt have a tune. I'm going back in and re doing my rockers. I think I may have tightened them too much on the preload.
     
  18. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    Re-did my rockers and it only gave me about a 1 or 2 inch improvement of vacuum. I found a leaky injector spewing gas out the top where it meets the fuel rail. Could this be a possible spot where I'm losing vacuum?
     
  19. toyman

    toyman Active Member

    Messages:
    874
    Likes Received:
    9
    Joined:
    Aug 25, 2008
    Leaking injector doesn't affect vacuum. That's likely a bad O ring. Check this site. You appear to be describing scenario 10 on the list. If it's late valve timing then you have your work cut out for you. Guessing the cam was not positioned correctly. Can you confirm the crankshaft and cam shaft sprockets were aligned and that the timing chain deflection was within spec.
     
  20. Kylebach14

    Kylebach14 New Member

    Messages:
    82
    Likes Received:
    0
    Joined:
    Mar 26, 2014
    When i installed my timing chain, I put it in dot to dot. Scenario 10 also says that it could be a possible intake leak? I deleted my ac and wasnt sure if anything from there would cause low vacuum. I plugged the plastic line by the passenger side fenderwell but I'm not sure if there is anything else?