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420A 420A turbo vacuum line problem 1psi boost

Posted by Hunteremerson17, Oct 10, 2018

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  1. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Liberty, Kentucky
    I recently bought a 99 eclipse GS that’s got a 420A motor that’s been turboed, I bought a 38mm external wastegate (6psi spring)and not really sure how to run the vacuum lines on it, as of right now it’s onlu pushing 1psi of boost and idles around -10 vacuum... I don’t have a clue what’s been done to the motor or what kind of setup they have... anything will help!
     

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  2. dsmcrzy

    dsmcrzy Proven Member

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    Post up some pics of the engine bay.

    The wastegate should have had some instructions with it on how to set it up. What ports you use on the wastgate will vary by manufacturer.
     
    My DSM:
    1996 Mitsubishi Eclipse N/T

    Street Build

    20g   manual
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  3. dustyboner

    dustyboner Proven Member

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    abq, New Mexico
    -10 is too low. 17-18 inHg at 5000ft above sea level so thats something like 20 inHg at sea level. Unless you have some crazy ass cam.
    how are you controlling fuel? FMU? megasquirt?
    does it cut out at 1 psi? if it does your probably in need of a fuel cut defenser of some flavor, to clamp the map sensor voltage.

    the wastegate vac. goes from the side port on the wastegate to any one of these:
    --turbo compressor housing
    --intercooler piping
    --intake manifold

    since your a 420a, i doubt that the innercooler piping has a vacuum fitting on it.
    if your turbo doesn't have a fitting on the compressor housing, go off the intake manifold.
     
    Last edited: Oct 10, 2018
  4. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Liberty, Kentucky
     

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  5. Hunteremerson17

    Hunteremerson17 Probationary Member

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    I Sent some pictures of the engine bay below..
     
  6. dustyboner

    dustyboner Proven Member

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    abq, New Mexico
    i had a nuespeed bar way way back but mine had yellow writing.
    any ways you need to cut the hose between the BOV and waste gate, insert a vacuum t, and run a hose from the T to the intake manifold
     
  7. dustyboner

    dustyboner Proven Member

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    abq, New Mexico
    here is your vacuum leak. hook the hose you just T'd in to one of these

    E8E3CA7C-E140-4515-A7BC-77DD0B30B6D9.jpeg
     
    Vegas smith likes this.
  8. silvreclips

    silvreclips Proven Member

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    Greenville, South Carolina
    A big thing I noticed was the vacuum port on the back of the intake has 3 ports, You only have 1 hooked up. You need to cap all of the extra ports. Your gauge may be reading incorrectly because of the extra ports being open.

    Is also looks like the BOV is connected to the wastegate but neither has reference to the intake manifold. Your BOV should go back to the intake manifold, and the wastegate should go back to the intake manifold. You can run 1 line and tee off if you choose to.

    Also what's going on with that catch can on top of the strut bar? Does the hood even close?
     
  9. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Joined Oct 10, 2018
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    Wastegate
     

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  10. dustyboner

    dustyboner Proven Member

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    upload_2018-10-10_6-4-36.png

    I can't even imagine why the is a tap on this wire off the cam sensor. If its not causing issues yet, im sure it will.
     
  11. Hunteremerson17

    Hunteremerson17 Probationary Member

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    the catch can hasn’t been mounted yet, it was laying down inside the engine bay and I put it up there to take pictures, but I’ll try to mount it somewhere else when I get the vacuum lines figured out, thanks for the help
     
  12. Hunteremerson17

    Hunteremerson17 Probationary Member

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    These are the only codes it’s showing as of now.
     

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  13. silvreclips

    silvreclips Proven Member

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    See post #3. You will need something to keep the ecu from seeing boost pressure.

    Whoever built this car did a very poor job. You need to look at what has been done to the fuel system to support this turbo. Do not go out and run this hard until you are sure everything is correct.
     
  14. Hunteremerson17

    Hunteremerson17 Probationary Member

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    is this the right way? I’m pretty sure I did the vacuum hoses as you said?
     

    Attached Files:

  15. Hunteremerson17

    Hunteremerson17 Probationary Member

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    I’m only 17, I just got my birth certificate and social security card yesterday in the mail, I’m going today to try to get my permit, so I won’t be driving it at all for atleast 6+ months, it’s only drove on the weekends for about 50 miles
     
  16. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Joined Oct 10, 2018
    Liberty, Kentucky
    0BEE0A92-447F-43E5-A20E-069B170F5B40.jpeg

    It builds about 3psi now and idles at 8psi vacuum now, as I said i don’t have a clue what’s been done to it or anything.
     
  17. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Liberty, Kentucky

    I put the wastegate vacuum line in the center, blocked off the left one, and the right one is connected to the blow off valve, it’s boosting 3psi now and idling around 8psi vacuum (950rpms)
     
  18. Hunteremerson17

    Hunteremerson17 Probationary Member

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    2psi more of boost but doesn’t seem to run much better than it already did, I don’t have a clue what it could be now. I run 93 octane in it as well, so does that mean it could be too rich or too lean for gas? I’m not sure about anything that’s been done too it but I did have to replace the old fuel pressure regulator and come to find out it had a aftermarket one as well and it was running through both regulators, so I took the aftermarket and the stock off and put a new stock one back on. It seemed to run better then
     
  19. silvreclips

    silvreclips Proven Member

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    What is the boost gauge connected to? You may have a leak on that line or at the gauge. You should be getting closer to 20"hg at idle. You can unhook the line and suck on it to see if it is holding pressure or of there is a leak. That would be an easy way to tell.

    I'm also glad to see you have a fuel pressure gauge, does it work? It looks like your maxed out at idle. It should be around 43psi. Don't worry about boost yet, get the car running good first and then we can work on the rest
     
  20. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Liberty, Kentucky

    Alrighty, so I found out the boost line is running into a T between the blow off valve and the right hose on the back of the motor, I took it off and blew through it and sucked through it, it doesn’t have a leak at all, and I got to looking and found out the fuel pressure gauge wasn’t hooked up to the battery so I ran wires and got it hooked up, it’s running between 39-40... so my next question is where does the boost gauge need to be at? Is it fine where it’s at?
     

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  21. silvreclips

    silvreclips Proven Member

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    Greenville, South Carolina
    The boost gauge is fine tapped into the BOV assuming the BOV doesn't have an internal leak. Hook the BOV straight to the intake and test again. See if the vacuum increases.

    The gauge also could be bad. Does the car run well at idle?
     
  22. Hunteremerson17

    Hunteremerson17 Probationary Member

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    The car runs decent, it just doesn’t like to idle that well when it’s cold, and if you’re driving it and push the clutch in the motor might die every once in a while unless you give it a little gas as soon as you push the clutch in
     
  23. Vegas smith

    Vegas smith Proven Member

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    The car probably has a lot of little stuff wrong with it. Do a boost leak test to fix all air leaks. I don't know what fuel pressure a 420a should have but find that out and set your pressure to that.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  24. Hunteremerson17

    Hunteremerson17 Probationary Member

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    Liberty, Kentucky
    Sounds like a plan
     
  25. dustyboner

    dustyboner Proven Member

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    abq, New Mexico
    Fuel pressure should be 47-50 psi with the stock FPR.
    With an adjustable FMU like a vortech SFMU and larger injectors it will be lower than that.

    Do you have a picture of the aftermarket one so i can ID it? Its a FMU that raises fuel pressure x number of psi per pound of boost pressure. Its so that you get the extra fuel you need to go with the increased air from the turbo.
    You definately need it, dont boost without it or you will destroy the motor from running too lean.
    Do you have a wideband o2?

    Also clear the codes and see if they come back. I can see in the last pics you posted that you have a missing link installed (so the map sensor doesnt see boost). So if its working correctly the map sensor code may be because of the disconnected vacuum lines.
    Same with the evap code. In stock form, the fitting with the 3 hoses on the back of the intake manifold connects to:
    - egr solenoid (side of head below cam sensor)
    - cruise control vacuum resivour (underneath intake manifold)
    - hard line on firewall ( goes to evap vent solenoid by gas tank)
     
    Last edited: Oct 11, 2018

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