Thread: Vacuum leak? I have my doubts.

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  1. #1 Vacuum leak? I have my doubts. 
    GT Level Member PWNED's Avatar
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    Recently coming from a 3.4/headers/rockers/intake setup. I just installed my Phenolic Full size IC and dropped to a 3.0 pulley with no KR @ 10.5 afr and 17* timing.

    Now my trims are all messed up. + 7 to 13 at idle. In certain spots at cruise I will hit high teens in both trims. As on my old setup I was +/- 5.

    For wot in this setup or old they are locked at 0.

    Now the reason I suspect it is not a vacuum leak is because when I remove my oil cap my ltft spikes to +16 (from +10-13) When I put the cap back on they drop back down to around 10.

    Now does going to a 3.0 from a 3.4 really draw that much air in to make that much of a difference other than wot?

    As I used RTV where it was needed to seal the supercharger and LIM to mounting surfaces.

    But I could be wrong. Maybe I have a leak somewhere besides the mating surfaces?

    Link to the scans.

    http://www.hptuners.com/forum/showth...013#post382013
    Last edited by PWNED; 05-04-2015 at 05:28 PM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq
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  2. #2 Re: Vacuum leak? I have my doubts. 
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    i assume no injector swap? i wouldnt expect it to throw it that far off at idle. it will definitely be leaner as the air charge is cooled and is getting more dense. seems like a lot as the BBV will be open at idle so the pulley shouldnt matter to much. due to the fact that your trims get worse when you pull the oil cap i would suspect that something is ****ed up in your PCV system. if you intercooler doesnt retain the PCV you should be venting the valve cover anyway.
    - 2001 Grand Prix XGT -- 11.21@124MPH
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  3. #3 Re: Vacuum leak? I have my doubts. 
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    I little update. I poured water on the injectors just as a hunch as the orings leaked a day prior (vac leak) but I installed new ones that day and all is good there.

    Next I poured water around the SC and IC by the snout and instantly started running like crap........
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq
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  4. #4 Re: Vacuum leak? I have my doubts. 
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    Still using the same injectors.
    The new Phenolic cores have functional front/rear pcv. No other modifications are needed as he states. If the pcv was messed up (with me pouring water around the snout area of the IC) it should not matter. If the pcv was messed up the oil cap should be hard to remove, right? But is not. I really don't know how I created a leak.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq
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  5. #5 Re: Vacuum leak? I have my doubts. 
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    Quote Originally Posted by PWNED View Post
    Still using the same injectors.
    The new Phenolic cores have functional front/rear pcv. No other modifications are needed as he states. If the pcv was messed up (with me pouring water around the snout area of the IC) it should not matter. If the pcv was messed up the oil cap should be hard to remove, right? But is not. I really don't know how I created a leak.

    it depends on what is messed up with the pvc but yeah some times. sounds like you have a vacuum leak up around the front somewhere.
    - 2001 Grand Prix XGT -- 11.21@124MPH
    - 2010 Chevy 2500HD LTZ -- Car hauler
    - 2011 BMW 328i Xdrive -- Wife's Daily
    - 2014 Ford F250 crew cab -- 6.2 liters of ford fail
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  6. #6 Re: Vacuum leak? I have my doubts. 
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    I am pretty sure I just found my vacuum leak. As you watch the video you can see the soap water being sucked in. Before hand I sprayed brake clean and stalled the motor out.

    https://www.youtube.com/watch?v=jY9E9UbW3p4

    https://www.youtube.com/watch?v=74QPKA-IMFA
    Last edited by PWNED; 05-05-2015 at 06:20 AM.
    02 Regal GS
    ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
    PB-------12.3 @ 110.......312hp/350tq
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