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Thread: Waste Gate Check

  1. #1
    Join Date
    Apr 2000
    Location
    Bonney Lake WA via Powder Springs GA
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    Question Waste Gate Check

    What is the proper way to check the waste gate actuator? I moved the rod to the read and pumped up the diaphragm. It started to move slowly and by about 3 inches it had moved all the way forward. The book said it should move quickly. I then pumped it up to 15 inches and it bled down to 3 fairly quick. If I pushed the rod back then the pressure raised back up to over 5.

    Is this good or bad? I am blowing black smoke on acceleration. The harder I accelerate the more smoke I blow. The injectors are new with less than 4K miles, new heads, and she seems to run pretty good, but I am only getting 12 miles to the gallon
    .
    Last edited by chris_maxwell; 08-09-2009 at 19:02. Reason: lbs rather than inches
    chris maxwell
    transplanted to Georgia from the great northwest, and now back to the Evergreen State
    1995 GMC ext cab K2500 HD 4:10 gears, 4" exhaust, Kennedy Chip 162,000 miles, Gear Vendor Under Overdrive, rebuilt transmission with trans go shift kit, time for head gaskets....
    maxwell9@rocketmail.com

  2. #2
    Join Date
    Feb 2000
    Location
    Montana
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    11,382

    Default

    If your wastegate actuator is normal and your vacuum tester does not have any leaks, it should hold a vacuum for a long time (several minutes at least). The diaphragm in the actuator should not leak.

    Black smoke is a usual first indicator that there's a lack of boost pressure. When the engine is idling, it should take considerable effort to move the wastegate actuator rod against the vacuum - using just your fingers on the rod (or pliers if it's hot). This is a quick test of the vacuum system that an owner can perform in his driveway. If the vacuum appears to be OK, but the engine is still producing black smoke during a WFO run, I'd replace the wastegate solenoid if it hasn't been done in a few years or 75K+ miles.

    Jim
    Last edited by More Power; 08-09-2009 at 20:21.

  3. #3
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
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    Default

    The vacuum system on these is subject to failure do to several things.
    The vacuum pump wears out, the wastegate solenoid (LH VC at the rear)
    The plastic lines break or crack.
    Wastegate acutator wears out and needs service.

    A turbo master will fix all these ills and you no longer need any of that anoying stuff.

    Set for a max boost of 10 PSI and its off to the rodeo.

    I have never used the Banks chip but the Heath chip works with the Turbo master and you will not get codes and or defuel if you have too much boost.

    Very simple to install and use. Very forgiving device that just plain works.

    I have one on my 95 and its just the best thing since sliced bread.


    If you decide to keep the vacuum system the pump should see 26"Hg at the pump and the reading should be steady.
    The reading at the wastegate actuator should be about 20"hg with engine at idle.

    A code 78 will set if the solenoid has an electrical fault but normally the ecm will not complain unless it sees no boost or way too much.

    Be sure the plastic lines are in good order as well as the rest of the system.

    Again the turbo master is the ideal device as it is a simple rod with a spring and a couple nuts to adjust it.

    Crank it down until you get 10 PSI under a hard pull (MAX) and your set.

    USE A PYRO and BOOST gauge with the the TM as you are now the only thing between a heavy foot and a melted six and a half


    Have fun

    Best

    Missy
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  4. #4
    Join Date
    Apr 2000
    Location
    Bonney Lake WA via Powder Springs GA
    Posts
    80

    Red face More info

    Thanks both Jim and Robyn for the response. I did measure the vacuum at idle, the vacuum is 26 going into the solenoid (new a few thousand miles ago) and about 16 coming out and going into the wastegate. I didn’t check the vacuum while driving; only idling as I borrowed the gauge. I replaced all of the plastic lines with rubber. I have no codes.

    If the wastegate doesn’t hold pressure (how much should it hold as I am holding about 3) then it is bad? As far as I know the tester holds pressure (I put my finger over it and it held). The rod moves freely with some resistance with the engine off, once in awhile it felt as though it wanted to stick when pulled to the rear. When the engine is running it is very difficult to move if I can move it at all.

    I am getting black smoke on mild acceleration. At times the truck has a different feel when going down the road (sometimes it wants to go and other times it just wants to smoke). I am putting front brakes and shocks on it this weekend. I have put about 6 grand into it the last year + so I am hoping I am getting close to being able to enjoy this thing for the next 100 K miles. I love my truck
    chris maxwell
    transplanted to Georgia from the great northwest, and now back to the Evergreen State
    1995 GMC ext cab K2500 HD 4:10 gears, 4" exhaust, Kennedy Chip 162,000 miles, Gear Vendor Under Overdrive, rebuilt transmission with trans go shift kit, time for head gaskets....
    maxwell9@rocketmail.com

  5. #5
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
    12,282

    Default

    If the wastegate actuator will only hold 3"HG then its got issues and needs to be replaced.

    Robyn
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  6. #6
    Join Date
    Apr 2000
    Location
    Bonney Lake WA via Powder Springs GA
    Posts
    80

    Default what should it hold?

    Has anyone checked their wastegate to see what it will hold? MY boost would peak at 10 for a second, and then go down to 7 and hold it while accelerating. I still had black smoke. I bypassed the solenoid and plugged straight into the wastegate from the pump and I had 29 PSI and no smoke, ran great. I only did that for a couple of miles. Since I have marine injectors in the truck, is it possible that my BANKS chip doesn’t allow enough boost to be produced? Their website says it will produce 10*11 psi max.
    How do you know for sure if your cat has a blockage? It may have got a fair amount of water in it when the head manifold went.
    chris maxwell
    transplanted to Georgia from the great northwest, and now back to the Evergreen State
    1995 GMC ext cab K2500 HD 4:10 gears, 4" exhaust, Kennedy Chip 162,000 miles, Gear Vendor Under Overdrive, rebuilt transmission with trans go shift kit, time for head gaskets....
    maxwell9@rocketmail.com

  7. #7
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
    12,282

    Default

    29 PSI is well along the road to a place you don't want to go.

    If your chip is programed right you should not get any codes no matter what the boost.

    The chip may still only allow the boost to run 7-8 pounds.

    With some serious fuel, you need about 10-12 PSI or your gonna get smoke.

    I am not familiar with the Banks chip so I can't say how its set up.

    The Heath chip will allow you to run whatever you desire until it melts.

    10-12 is all these engines need without a charge cooler.

    The waste gate actuator should hold vacuum until its released. If yours leaks off replace the sucker.

    If you can run 29 PSI and not get any codes, I would install a turbo master and adjust it to peak at no more than 10-12 PSI and ditch the vacuum system altogether.

    Just leave the waste gate solenoid plugged in to keep the computer happy.

    You can cap the hose connections on the solenoid and either just unhook the vacuum pump or remove it altogether from the idler assembly.

    Leaving the bracket and the pulley part will allow the use of the same belt (Good Plan)

    The turbo master is a neat clean and simple way to go.

    Best

    Robyn
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

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