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Do I need a boost fooler? Whats my problem?

Discussion in 'GM 6.5 Diesel Engines' started by Z79outlaw, May 11, 2008.

  1. Z79outlaw

    Z79outlaw Its tougher in Wisconsin

    Ok the I've alwayse kind of liked the factory boost set up it was always reliable and it'd peak at 12 and hold 10 psi until 3000 rpms whenever I got on her and she decline from there. Well the pump started going south and it would only hold 5 psi, before I replaced it with a home-made turbo master. Well thats been working great for me until this weekend, I get a intermittent check engine light now that goes on occasionally and power kicks in and out whenever I go WOT, also no smoke anymore, the truck is really sluggish now. So my question is what am I missing here? A boost fooler? So the ECM still thinks the factory system is operating and working like normal or what?
     
  2. chrisk1500

    chrisk1500 New Member

    875
    0
    May 5, 2008
    Wire in a 10k pot into the MAP sensor....yellow wire IIRC...
     
  3. Z79outlaw

    Z79outlaw Its tougher in Wisconsin

    Ok, thanks I thought that was what was needed, I thought it was the green wire though
     
  4. chrisk1500

    chrisk1500 New Member

    875
    0
    May 5, 2008
    Middle wire....whatever color that is...
     
  5. Z79outlaw

    Z79outlaw Its tougher in Wisconsin

    Well that made a hell of a difference, just got done soldering it in, and back from the test drive, I still have the SES light, but we'll see if that goes out tommorow on the commute to work, otherwise I've got a little more digging to do. I cant beleive I used the factory system for so long now:mad2:
     
  6. Acesneights1

    Acesneights1 New Member

    10,018
    10
    May 5, 2008
    Northeast CT
    A Heath Maxi Torque will solve that problem):h
     
  7. JiFaire

    JiFaire Lieutenant Staff Member Lead Moderator

    7,596
    173
    Feb 10, 2008
    Alberta, Canada
    What he said...

    A new chip, or reflashed ECM (PS- update your signature so we don't have to guess which kind of rice-burner you're driving) will solve your problems...

    What's happening is your stock programming is set to allow only a certain amount of boost; when you exceed that with your Turbo-Master, the stock PCM reads that as an overboost condition, and seeks to remedy that problem.

    Since your PCM-controlled WG controller is no longer in the game, it can't turn down the boost, so it next moves to protect the engine by cutting back on the fuel.

    Wiring in the 10K pot lets you change what the PCM 'sees' as the true boost value... essentially 'fooling' it into thinking things are normal. If you still have the light, it means you need to adjust the POT some more, 'cause your PCM is still seeing too much or no boost.

    A reflash will have a different warning value programmed into the PCM, as well as the added benefits of higher fuel delivery, changed torque curve, modified shift points and lockup values, etc.

    Best thing you can do for your truck after air and exhaust, IMHO.
    ______________
    Please include your vehicle details in your signature line. Did you read the FAQ's and search before posting?
    =================

    1994 Silverado SLT 2500, ExtCab LB, 2wd, 3.73 gears, "F" engine, 300 000 km, Snorkle-ectomy and Airbox mod, TCC mod, Mandrel-bent crossover, 3" mandrel-bent downpipe, 3" Duramax resonator, 4" constant-radius out the back.

    Parts Added: Heath PMD Isolator.Heath Max-E-Torq 2.0, Heath Turbomaster, Heath Severe-Duty Fan Clutch, Heath HO LP, Heath Injectors, Heath (Bosch) Duratherm Glowplugs
     
    Last edited: May 17, 2008
  8. mangus580

    mangus580 Member

    316
    1
    Jun 3, 2008
    Western NY
    I have often wondered about the effects of a boost fooler.

    If you are tricking the computer into thinking your boost is lower... doestn that make the fuel rate lower by comparison?

    I am noticing the same issue with the wife's 99 since I did the Turbo master (although it never trips the light.... but the code is almost always pending)
     
  9. 96TD

    96TD Recruit

    107
    0
    May 6, 2008
    Wilmington, MA
    In my opinion, the boost fooler does reduce the fueling a little. I have a homemade one. When I put it in, I no longer got the SES light, and had no more limp mode defueling, but it seemed like it had less power than before I put it on. I have since removed it after putting in a Heath Max-E-Tork. Which by the way is awesome!
     
  10. Z79outlaw

    Z79outlaw Its tougher in Wisconsin

    I too have noticed a loss of fuel especially at the higher rpms, and after 20 mins or so of driving my truck goes back into limp mode usually, I dont know, I'm gunna throw a Cummins in this truck and just get it all over with, it took me way to long to realize I want this 6.5 to be somthing that it never will be.
     
  11. Turbine Doc

    Turbine Doc Just Another Diesel Guy

    You aren't getting less fuel, you are getting same fuel unless chipped/flashed requesting fuel, boost without fuel is just more hot air, what fooling or a TM does with stock programming is that it doesn't clip boost where it normally would ie cruising at 70-75 mph stock programming will run 2-3 psi, climb a hill you'll get acceleration/boost up to 7-10 for short burst, then cut back to GM programmed low boost 2-3.

    With TM/fooling you will sustain boost at what ever you set boost for so that once fuel is added you'll already have "air on tap" to work/burn the extra fuel, there is a point of diminished return of adding more boost for boost sake,

    GM-X turbos are restrictive in outlet backpressure vs boost developed, you'll need more fuel to overcome backpressure. Which is why Slim Shady & myself are playing with the non wastegated Mitsubishi TD07-22A turbo big wheel & compressor lot of cfm moved, with low backpressure max I've recorded is 25 psi back pressure for 13 psi boost, GM-8 for same boost levels was 35+ psi backpressure.

    Exaggerated expalanation but compressor is trying to create push/air to be fed to engine, but back pressure in turbo is trying to slow the process down, remove backpressure the better a turbo can make sustainable boost, GM-X series turbos need more fuel/timing which stock program can't provide to help overcome backpressure, so eventually if you want to maximize power you'll need more fuel, then once you get more fuel you'll want a better turbo.
     
  12. mangus580

    mangus580 Member

    316
    1
    Jun 3, 2008
    Western NY
    I guess my point was.... if your computer things you are only getting 5psi of boost, when you really have 10psi.. .isnt it only going to provide fuel for 5psi, and not the 10psi you really have?
     
  13. JiFaire

    JiFaire Lieutenant Staff Member Lead Moderator

    7,596
    173
    Feb 10, 2008
    Alberta, Canada
    Nope. The PCM doesn't match the fuel to the boost... it just feeds fuel based on your foot.
     
  14. mangus580

    mangus580 Member

    316
    1
    Jun 3, 2008
    Western NY
    Well now I understand!

    In that case... boost fooler, here I come...
     
  15. 96TD

    96TD Recruit

    107
    0
    May 6, 2008
    Wilmington, MA
    I just got a reflashed computer, and yanked my boost fooler. Want one?
     
  16. 96TD

    96TD Recruit

    107
    0
    May 6, 2008
    Wilmington, MA
    Mike,
    Check your mail starting...tomorrow.
     

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