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Sluggish '99 5.7 vortec K2500 CCSB OBS

This is a discussion on Sluggish '99 5.7 vortec K2500 CCSB OBS within the Technical / Maintenance forums, part of the General Discussion category; Hey guys! I picked up my “new to me 99 k2500 CCSB OBS” last week and have been trying to ...

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    Sluggish '99 5.7 vortec K2500 CCSB OBS


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    Hey guys! I picked up my “new to me 99 k2500 CCSB OBS” last week and have been trying to get it where I want or think it should be.
    My question today is about it being sluggish… When not romping on the throttle the truck runs smooth and without missing a beat, which is great! However we don’t (or at least I don’t) get my trucks with V8’s so that I can go under the speed limit and not haul some A$$ every once in a while right? Any ways when I romp on the pedal it just drives like I’m at 40-50% throttle? What could it be?
    I have the 5.7 vortec with a 4l80e and running 35’s… I’m thinking the 35’s are my problem since I have never had larger than 285’s on any of my vehicles? I’m not sure what the gearing is yet, could that affect my throttle response? I would like to get the tires spinning a little bit or at least be able to pass on the highway (super slow acceleration).
    I’m hoping someone will have some ideas on how to wake this beast up? Any help is appreciated…
    -Thanks

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Gearing is 3.73... Is that too high for 35's.

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    doesnt matter what gears you have 35's are going to be heavy feeling when accelerating and braking
    Last edited by ToyHauler; 07-02-2013 at 04:36 AM.
    99 GMC Yukon SLE 4dr
    KYB monomax, air lift, tekonosha, reese dual cam, bfg at/ko

    87 Firebird, 07 Monte Carlo lt, 98 Bonneville SSE, 04 F550 CC 4wd service body

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Hmmm... I don't seem to have any trouble stopping... it's just accelerating. I am going to clean the MAF sensor since I read that could be part of the problem. I'm also going to see if I can find a fuel pressure gauge to test the pump... does any one know what the optimum fuel pressure should be?

    Smaller tires are not an option right now since the truck came with a 6" lift and I don't want to take it off and buy new tires...

    Thanks,
    All help is appreciated

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    i got new delphi everything mine is 58 key on engine of and goes into the mid 60's running
    99 GMC Yukon SLE 4dr
    KYB monomax, air lift, tekonosha, reese dual cam, bfg at/ko

    87 Firebird, 07 Monte Carlo lt, 98 Bonneville SSE, 04 F550 CC 4wd service body

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    3.73's with 35's, and a 4L80E....mmm, its not going to be a powerhouse with a 5.7.

    The 4L80E had higher gearing in 1st than the 4L60E..so it feels sluggish right off, from that. Add to that, the loss of mechanical advantage from the taller tires.

    This is exactly why I wouldnt consider a 5.7L 2500 or 3500 when truck hunting, all the ones I drove, felt...underwhelming for a 3/4 ton...when you consider that other 3/4 and 1 ton trucks can be had with 400hp Diesels, and 300+hp Big blocks, I just couldnt see getting one with the same powertrain as a 1/2 ton. BUT...that said, it shouldnt be sluggish, it should feel like a 1/2 ton truck..
    95 K3500 Silverado
    Reg cab, long bed
    454TBI/4L80E/BW4401
    4.10's
    150K

    95 K2500 Silverado
    Reg Cab/Long bed
    6.5 Turbo Diesel,
    4.10's
    128K miles

    94 K1500 Sierra Z71 OFF ROAD
    Reg Cab, Stepside
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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    3.73's with 35's, and a 4L80E....mmm, its not going to be a powerhouse with a 5.7.

    The 4L80E had higher gearing in 1st than the 4L60E..so it feels sluggish right off, from that. Add to that, the loss of mechanical advantage from the taller tires.

    This is exactly why I wouldnt consider a 5.7L 2500 or 3500 when truck hunting, all the ones I drove, felt...underwhelming for a 3/4 ton...when you consider that other 3/4 and 1 ton trucks can be had with 400hp Diesels, and 300+hp Big blocks, I just couldnt see getting one with the same powertrain as a 1/2 ton. BUT...that said, it shouldnt be sluggish, it should feel like a 1/2 ton truck..
    95 K3500 Silverado
    Reg cab, long bed
    454TBI/4L80E/BW4401
    4.10's
    150K

    95 K2500 Silverado
    Reg Cab/Long bed
    6.5 Turbo Diesel,
    4.10's
    128K miles

    94 K1500 Sierra Z71 OFF ROAD
    Reg Cab, Stepside
    350 TBI
    2" lift, 33's
    201K miles

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    When I got the truck I was expecting a lot more since everyone talks up the vortec 350... not only that but it has a superchips sticker on the truck. So at first I though the previous owner just put the sticker on for the "cool" factor... so I got ahold of him and asked if the truck was chipped, tuned, or just had a "cool" sticker and the answer was chipped...

    After that I started reading up to find out what chip it may have and I have now recently found out that no one makes a chip for this engine... Can anybody give any input on the chip thing?

    Next is the tires... it's throwing my speedo off since it was not re-calibrated! Could this affect anything other then me having no idea how fast I'm going, which I'm used to cuz I had an 03 2500hd and those clusters from 01-07 are total poop piles.

    One last thing before I go back to work... hehe... are my expectations totally screwed since I'm kind of expecting the 5.7 to do what my 6.0 did?

    454/4x4... if I could of found a BBC I would have jumped all over it... I was without a vehicle for almost 3.5 months since my 03 got stolen. So when I finally found what I thought was a sold truck at a more then sold price I took it... I still think I stole the truck but now I want to drive like it's stolen.

    -Thanks

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Contact Blackbear performance for a real computer tune. They can remove the torque management from the computer to give ya some more juice. Your have an 80e so your trans can handle a little more abuse.
    04 1500 Z71 6.0 LQ4 swap, BlackBear 06+ Grill/Hood, Vette servo, 3 BL,RC Keys, Truxedo, Bull Bar,KC, Cooper ST's Bilstein 5100's Tow's, Pypes M-80.


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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    the 5.7 is never going to be as good as the 6.0. but it will tow stuff if you are patient, which it was designed for and sounds like you are not patient. there is a reason why the 5.7's are cheap. if you want something that will tow things quickly you will have to go back to a 6.0 or diesel
    99 GMC Yukon SLE 4dr
    KYB monomax, air lift, tekonosha, reese dual cam, bfg at/ko

    87 Firebird, 07 Monte Carlo lt, 98 Bonneville SSE, 04 F550 CC 4wd service body

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Blue 04 Z71, thanks. Do you know anything about the chip question that was asked?

    ToyHauler, you are correct... I do not have patients what-so-ever! And I do miss my 6.0 very badly.... I have not towed with this truck yet, but now I'm not looking forward to it.

    Ok on to updates... I finally got a fuel pressure test kit and I was consistently at 61 while the pump was cycling key on engine off. Now is where it gets weird. As soon as the pump is done cycling the needle drops rapidly to 0. While running I was at 58 and with throttle I got to 65. Not being to familiar with this test we hooked up my father-in-laws 03 6.0. He was at 58 key on engine off and when the pump was done cycling he went from 58 to 55 and the pressure held... which mine didn't. Any idea why my truck didn't hold the pressure and his did, is it just due to the fact that his truck is newer?

    Next, I am getting two codes when the truck is scanned. 122 and 1122 and apparently they are both for the TPS(that's what the AZ guy told me)... not sure what the difference in the two is but I'm going to replace it this week and will update if there is any noticeable difference.

    -Thanks

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Hey guys, I got some new updates...

    We replaced the fuel pump and filter, so no more fuel pressure issues. The truck starts ten times easier then before and I may have saved needing to replace the starter sooner than later. Also replaced the TPS and it seemed to help out with the throttle response.

    Next is the bad news... she died on me on the way home(60 mile trek). I am thinking that the thermostat went out and the truck over heated. This happened in about 2-3 minutes at high speeds(80mph). Lights went on, on the dash, and the truck died... once pulled to safe location we let the truck cool down and added some water(it was 11:30pm and that's all I had). Once we started looking around, the engine compartment was soaking wet, on the passenger side and not a single busted line. once filled with water we heard it boiling in the block and still no leaking. It seems to me like the thermo went out and the antifreeze shot out threw the cap(yes the cap was still there).

    After all this we waited about an hour to see if we could turn her over and she didn't even pretend to start. After continuing to check her out we noticed that it looks like antifreeze got into the oil... I'm thinking she's getting a new(rebuilt) engine. Turned the key twice nothing and on the third, heard a quick wine and pop and that was it... we called the tow truck and she's at the shop today waiting for a rebuilt 350 to be dropped in.

    If any of you guys have some inexpensive upgrades I should do, let me know. I know I have read about replacing the spider with an aftermarket one that is better, does any one have a name or brand so I can price it out? Also, I have read about replacing the intake gasket since the stock gasket is crap, any idea on which I should have them use?

    -Missing her already

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    delphi spider and felpro gaskets, they have a set for doing the lower with come with the other gaskets except only one valve cover gasket. it probably hydrolocked from the intake manifold gasket issues these have. alot of times if you just take the plugs out and see if it cranks it will shot the water out. just make sure you clean the rad and condenser fins, give it a new thermostat you should be good with the overheating if you are getting a rebuilt engine. i would have tried to save yours if it was me at most likely needed head gaskets, 350's are tanks
    99 GMC Yukon SLE 4dr
    KYB monomax, air lift, tekonosha, reese dual cam, bfg at/ko

    87 Firebird, 07 Monte Carlo lt, 98 Bonneville SSE, 04 F550 CC 4wd service body

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    If I had the time I would have tried to save it by doing what you suggested or I would have rebuilt the engine myself... however I have more money then time right now and that's not saying a lot since I don't have very much money either... The nice thing is I will get a warranty on the rebuild which I don't get doing it on my own. I will be going threw the truck with a fine tooth comb once I get it back.... I should have it on 7/18, but then she will be parked from the 19th-27th while I'm out of town... I will try to update once I get the truck back(before I leave).

    Any pointers for breaking in a rebuild?

    -Thanks

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    should probably ask your builder, there are varied opinions on the internet. most say take it easy for a while(vary engine speed), regular dino oil, and change it after a thousand miles or so
    Last edited by ToyHauler; 07-12-2013 at 07:59 PM.
    99 GMC Yukon SLE 4dr
    KYB monomax, air lift, tekonosha, reese dual cam, bfg at/ko

    87 Firebird, 07 Monte Carlo lt, 98 Bonneville SSE, 04 F550 CC 4wd service body

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    If you had the coin and some time you could drop in a 6.0. Just need a motor and a harness from nelson performance. Since its a 96+ you already have the high pressure fuel pump.
    04 1500 Z71 6.0 LQ4 swap, BlackBear 06+ Grill/Hood, Vette servo, 3 BL,RC Keys, Truxedo, Bull Bar,KC, Cooper ST's Bilstein 5100's Tow's, Pypes M-80.


    1989 Silverado 2500 94+grill, Ram air hood, Mild built 355, Th400,

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Quote Originally Posted by ToyHauler View Post
    delphi spider and felpro gaskets, they have a set for doing the lower with come with the other gaskets except only one valve cover gasket. it probably hydrolocked from the intake manifold gasket issues these have. alot of times if you just take the plugs out and see if it cranks it will shot the water out. just make sure you clean the rad and condenser fins, give it a new thermostat you should be good with the overheating if you are getting a rebuilt engine. i would have tried to save yours if it was me at most likely needed head gaskets, 350's are tanks
    350's are tanks for sure. Bought my dads 96 tahoe with 95000 miles and the kid overheated it and said the motor was junk. Took the heads off and the cyl's still had cross hatching. Threw on some new head gaskets and it runs like a champ.
    04 1500 Z71 6.0 LQ4 swap, BlackBear 06+ Grill/Hood, Vette servo, 3 BL,RC Keys, Truxedo, Bull Bar,KC, Cooper ST's Bilstein 5100's Tow's, Pypes M-80.


    1989 Silverado 2500 94+grill, Ram air hood, Mild built 355, Th400,

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Quote Originally Posted by ToyHauler View Post
    delphi spider and felpro gaskets, they have a set for doing the lower with come with the other gaskets except only one valve cover gasket. it probably hydrolocked from the intake manifold gasket issues these have. alot of times if you just take the plugs out and see if it cranks it will shot the water out. just make sure you clean the rad and condenser fins, give it a new thermostat you should be good with the overheating if you are getting a rebuilt engine. i would have tried to save yours if it was me at most likely needed head gaskets, 350's are tanks
    350's are tanks for sure. Bought my dads 96 tahoe with 95000 miles and the kid overheated it and said the motor was junk. Took the heads off and the cyl's still had cross hatching. Threw on some new head gaskets and it runs like a champ.
    04 1500 Z71 6.0 LQ4 swap, BlackBear 06+ Grill/Hood, Vette servo, 3 BL,RC Keys, Truxedo, Bull Bar,KC, Cooper ST's Bilstein 5100's Tow's, Pypes M-80.


    1989 Silverado 2500 94+grill, Ram air hood, Mild built 355, Th400,

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Quote Originally Posted by Blue 04 Z71 View Post
    If you had the coin and some time you could drop in a 6.0. Just need a motor and a harness from nelson performance. Since its a 96+ you already have the high pressure fuel pump.
    I wish I new that before I committed to the rebuilt 5.7!!! I would have loved to get the 6.0 again!!! Is it as simple as an engine swap with a new harness or is there a lot of fab that needs to be done? I still may do this in the future... I might be getting a 99 suburban with the 5.7 but it has about 300K on the clock and has been sitting for about 4-5 years. Don't worry if I get it... its going to be free If I end up getting the burb I may swap it for the rebuilt 5.7 and drop a 6.0 in my truck... hmmmm

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    Re: Sluggish '99 5.7 vortec K2500 CCSB OBS

    Quote Originally Posted by GotCha21 View Post
    I wish I new that before I committed to the rebuilt 5.7!!! I would have loved to get the 6.0 again!!! Is it as simple as an engine swap with a new harness or is there a lot of fab that needs to be done? I still may do this in the future... I might be getting a 99 suburban with the 5.7 but it has about 300K on the clock and has been sitting for about 4-5 years. Don't worry if I get it... its going to be free If I end up getting the burb I may swap it for the rebuilt 5.7 and drop a 6.0 in my truck... hmmmm
    Need conversion motor mounts (about 100 bucks), motor, harness, computer and a tune, and some fuel line adapters. There are some good write ups on LS swaps.
    04 1500 Z71 6.0 LQ4 swap, BlackBear 06+ Grill/Hood, Vette servo, 3 BL,RC Keys, Truxedo, Bull Bar,KC, Cooper ST's Bilstein 5100's Tow's, Pypes M-80.


    1989 Silverado 2500 94+grill, Ram air hood, Mild built 355, Th400,

 

 
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