Pontiac Grand Prix Forums : Grandprix
 

Grand Prix Forums is the premier Pontiac Forum on the internet. Registered Users do not see the above ads. Please Register - It's Free!

Pontiac Grand Prix Forum - Welcome Register today! Contact us!

Results 1 to 17 of 17
  1. #1
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default mpgs and power back! (throttlebody cleaning)

    This has been a long time coming. For the past 2 years I've been trying to figure out the loss of MPGs and random hard starting (thought it was my fuel pump going slowly). After watching a video on youtube I suspected my throttlebody. Apparently carbon build up in normal on these 3.8L throttlebodies (I know quite a bit about these things but didn't know that!) Anyway, holy hell was mine bad!!!

    I removed it and cleaned it up really well. Took before pics of both sides (note how black the inner side was!!) Anyway, on my drive to work today, back to 30-31mpg on the highway. Throttle response is WAY better, and the hard starting is gone.

    I'm sure there's a thread on this but wanted to share my experience.

    I also removed my 2004 silverado's throttle body and cleaned that (wasn't nearly as bad carbon wise). I will be checking my wife's 06 base grand prix tonight.

    Last pic is of the supercharger body. I just bought new fluid to once again swap for the super charger... only way to clean this passage is to remove the upper supercharger I'm assuming? If I'm going that far and have to already remove the fuel rails, I might as well remove the upper intake, thermostat, heater helper hoses and replace them (with the aluminum ones), replace the belt and coolant hoses. And do a coolant swap.

  2. #2
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)




    Sent from my iPhone using Tapatalk

  3. #3
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
    Join Date
    Sep 2009
    Location
    Rogers, MN
    Posts
    20,659
    Chats
    80966

    Default Re: mpgs and power back! (throttlebody cleaning)

    You don't have to clean the supercharger mouth, there would be no difference in how it performs even if it was clean. Ideally you want to remove the rotor pack, seal off the neddle bearings and go to town with some oven cleaner or really good brake cleaner and a soft brush to get all of it off. The EGR pipe in the opening there is what causes the soot to stick to the throttle body.

    The reason your silverado doesn't get that problem is because there is no EGR valve on those engines, 2000/2001 was the last year. They just get a little oil/grime build up from the factory PCV system.

    SMGPFC Member #1

  4. #4
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    Thanks for the response DIRKA DIRKA (your avatar is killing me ahahah!)

    So I could technically block off the far end, and the EGR passage and clean it out, heck I could use my shopvac to ensure i suck stuff out while I clean it...

    We'll see, that worries me a bit, I don't want that crap getting sucked into the motor.

  5. #5
    GTP Level Member cheatah faheatah's Avatar
    Join Date
    May 2016
    Location
    Rouge Island
    Posts
    856
    Chats
    2395

    Default Re: mpgs and power back! (throttlebody cleaning)

    Your before picture looks just like my 2006 n/a did before cleaning. I likened it to burnt maple syrup...lol.
    not what it looks like

  6. #6
    GT Level Member
    Join Date
    May 2017
    Location
    Dirtyzville, Mizzery
    Posts
    285
    Chats
    651

    Default Re: mpgs and power back! (throttlebody cleaning)

    Quote Originally Posted by SC06GT View Post
    Thanks for the response DIRKA DIRKA (your avatar is killing me ahahah!)

    So I could technically block off the far end, and the EGR passage and clean it out, heck I could use my shopvac to ensure i suck stuff out while I clean it...

    We'll see, that worries me a bit, I don't want that crap getting sucked into the motor.
    Just take the blower off and clean it.

    It's easy to do. You could in theory smooth out the inlet to make it easier on yourself instead of scrubbing everything out, too.
    1999 Chevrolet Silverado K1500 Classic Z71 - Intake/Gibson Exhaust - The Daily
    2004 Chevrolet Corvette MRM A4 - AFE S2 Intake/TSP Catless LT's/3" ORX/C6 ZR1 Wheels/Exhaust Tips
    Sold WBody's: '98 GT, '98 GTP, '00 GTP, '03 GTP, '05 GXP

  7. #7
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    Looks like removing the blower requires removing the fuel rail, correct? Along with some vaccum lines, the rear plug wires ect... I need to change the supercharger oil, assuming that would be best done after this, lol.

  8. #8
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    would be it worth anything to clean the EGR valve? Those damn things are troublesome on aging cars.

  9. #9
    GT Level Member
    Join Date
    May 2017
    Location
    Dirtyzville, Mizzery
    Posts
    285
    Chats
    651

    Default Re: mpgs and power back! (throttlebody cleaning)

    Quote Originally Posted by SC06GT View Post
    Looks like removing the blower requires removing the fuel rail, correct? Along with some vaccum lines, the rear plug wires ect... I need to change the supercharger oil, assuming that would be best done after this, lol.
    Removing the blower is a few steps...yeah. Fuel rail is four, 10mm nuts. That just pops right out and you can slide it aside to the right hand side of the engine bay after you've un-plugged the sensors around it on the harness and the injector clips. You'll need a 15mm wrench to push the tensioner down to remove the belt. Take apart whatever intake system you've got, unplug the throttle body...then on the back side of the blower you've got a couple worthless brackets with the main o2 plug and the MAP sensor. After all that business is out of the way, you'll need to unbolt the blower itself...be sure to unplug the BBV and any other misc. brackets like the EGR and such so you don't bend/damage stretch anything. It actually is very straight forward and simple. I even think the '04+ blower gasket is metal and re-usable. If not; they're like $10 at the blower parts store listed under the Intake Plenum Gasket. It'll come with the O-Rings and everything you'll need to stab it back on, too.

    Quote Originally Posted by SC06GT View Post
    would be it worth anything to clean the EGR valve? Those damn things are troublesome on aging cars.
    I deleted the EGR on every 3800 I've ever owned. No more carbon build-up, no issues if the valve fails, no chances of hunting a super hard to find vacuum leak via the gold accordion tubing, not to mention it really cleans up the engine bay. Nothing but positives. Some people say you lose gas mileage but I never noticed anything.
    1999 Chevrolet Silverado K1500 Classic Z71 - Intake/Gibson Exhaust - The Daily
    2004 Chevrolet Corvette MRM A4 - AFE S2 Intake/TSP Catless LT's/3" ORX/C6 ZR1 Wheels/Exhaust Tips
    Sold WBody's: '98 GT, '98 GTP, '00 GTP, '03 GTP, '05 GXP

  10. #10
    SE Level Member
    Join Date
    Jan 2012
    Location
    Valencia
    Posts
    72
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    Quote Originally Posted by blueguy91 View Post

    I deleted the EGR on every 3800 I've ever owned. No more carbon build-up, no issues if the valve fails, no chances of hunting a super hard to find vacuum leak via the gold accordion tubing, not to mention it really cleans up the engine bay. Nothing but positives. Some people say you lose gas mileage but I never noticed anything.
    dumb question. how do you delete it? block off plates? does this make the car not pass smog? I'm in CA (FML)....
    Daniel - Code name ILMODC (il-maude)
    Current ride: 2000 GT, 1998 GTP (wifes) -
    Work in Progress: 1987 Trans Am KnightHawk Edition (5.3 LSSwap)

  11. #11
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
    Join Date
    Sep 2009
    Location
    Rogers, MN
    Posts
    20,659
    Chats
    80966

    Default Re: mpgs and power back! (throttlebody cleaning)

    Remove it, block the 2 ports and tune out the codes.

    It would still pass an emission test as the EGR is only active once the vehicle is running and certain speed/rpm/load are met. Basically it's only going to turn on at freeway speeds in 4th gear. If the vehicle is subject to a visual inspection and they know exactly what the vehicle should and shouldn't have, it would likely fail.

    You could still block off the ports and leave the EGR in place to pass visual and disable the codes in the computer.

    SMGPFC Member #1

  12. #12
    GT Level Member
    Join Date
    May 2017
    Location
    Dirtyzville, Mizzery
    Posts
    285
    Chats
    651

    Default Re: mpgs and power back! (throttlebody cleaning)

    Simple enough; I had a penny RTV'd in each bracket.

    Worked like a charm.

    I think ZZPerformance still sells the nice looking aluminum pieces to block it off for like 10 bucks.
    1999 Chevrolet Silverado K1500 Classic Z71 - Intake/Gibson Exhaust - The Daily
    2004 Chevrolet Corvette MRM A4 - AFE S2 Intake/TSP Catless LT's/3" ORX/C6 ZR1 Wheels/Exhaust Tips
    Sold WBody's: '98 GT, '98 GTP, '00 GTP, '03 GTP, '05 GXP

  13. #13
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    So If I block the EGR valve off and remove it.... I'll have a CEL/Check engine light though, correct? What are the benefits of removing that unit? I mean you stated a few things.... I could at the very least try it.

    Would I need both the exhaust and intake blocks?

    https://zzperformance.com/3800/exhau...off-plate.html

    I don't have my car infront of me so I can't just look lol.

  14. #14
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
    Join Date
    Sep 2009
    Location
    Rogers, MN
    Posts
    20,659
    Chats
    80966

    Default Re: mpgs and power back! (throttlebody cleaning)

    Read post #9 again, that will answer your one question, there really isn't much more to it. It stops carbon build up and the smaller chance of the part failing someday or being an issue.

    Yes the CEL/SES will be on if you don't tune the code out.

    SMGPFC Member #1

  15. #15
    GT Level Member
    Join Date
    May 2017
    Location
    Dirtyzville, Mizzery
    Posts
    285
    Chats
    651

    Default Re: mpgs and power back! (throttlebody cleaning)

    Quote Originally Posted by SC06GT View Post
    So If I block the EGR valve off and remove it.... I'll have a CEL/Check engine light though, correct? What are the benefits of removing that unit? I mean you stated a few things.... I could at the very least try it.

    Would I need both the exhaust and intake blocks?

    https://zzperformance.com/3800/exhau...off-plate.html

    I don't have my car infront of me so I can't just look lol.
    Yes; you need both plates to block off both parts of the EGR.

    As Cam said as well; I explained that all in post #9. You will need a tune to get rid of the CEL.
    1999 Chevrolet Silverado K1500 Classic Z71 - Intake/Gibson Exhaust - The Daily
    2004 Chevrolet Corvette MRM A4 - AFE S2 Intake/TSP Catless LT's/3" ORX/C6 ZR1 Wheels/Exhaust Tips
    Sold WBody's: '98 GT, '98 GTP, '00 GTP, '03 GTP, '05 GXP

  16. #16
    SE Level Member SC06GT's Avatar
    Join Date
    Jun 2016
    Location
    Wisconsin
    Posts
    25
    Chats
    0

    Default Re: mpgs and power back! (throttlebody cleaning)

    10-4 thanks. ZZP states I'll lose 1mpg. Lamesauce.

  17. #17
    GTP Level Member cheatah faheatah's Avatar
    Join Date
    May 2016
    Location
    Rouge Island
    Posts
    856
    Chats
    2395

    Default Re: mpgs and power back! (throttlebody cleaning)

    Quote Originally Posted by SC06GT View Post
    10-4 thanks. ZZP states I'll lose 1mpg. Lamesauce.
    https://youtu.be/gYdXkUNuFzQ
    not what it looks like

Similar Threads

  1. new to pontiac no power to back door
    By sleeperpontiac in forum General Tech Discussion
    Replies: 1
    Last Post: 07-07-2015, 10:04 AM
  2. RPMs all over the place and MPGs down?
    By h0wl0ngcanitbe in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 10
    Last Post: 06-08-2012, 09:46 AM
  3. Straight Hwy MPGs
    By TLSheff in forum Off Topic Discussion
    Replies: 12
    Last Post: 02-16-2011, 10:37 PM
  4. Mpgs running in 3rd gear
    By Knipdm01 in forum Off Topic Discussion
    Replies: 10
    Last Post: 12-29-2009, 12:14 PM
  5. MPGs
    By BwolfGT in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 8
    Last Post: 12-06-2009, 08:19 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •