Reduce Engine Power

Discussion in 'GM Powertrain' started by 22inSilverado, Apr 16, 2009.

  1. 22inSilverado

    22inSilverado New Member

    I have a 2005 1500 silverado It has been recently every once in a while going in to reduced engine power and i have notice that also the check engine light has came on, i had the check engine light check and it said that the O2, now the truck is straight piped and i don't have mufflers on the truck so if any one can think of something or know of something it would be awesome to know thanks!!!
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    reduced engine power

    Did you leave both front and rear 02s on truck when you modified the exhaust?
  3. 22inSilverado

    22inSilverado New Member

    Yes they are all 4 still there the only thing that isn't is the mufflers
  4. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Do you still have the cat con in place?

    You say it has NO muffler? Do you mean NO muffler, or maybe some sort of muffler built into the straight pipes?
    No muffler would wake the dead! There must be some baffles in your pipes, right?

    My guess is you thrown off the engine tuning so much-with the no muffler exhaust- that "it" the ECM thinks something is dramatically wrong, and it drops into some sort of limp home mode.

    Second guess, if the cat cons are in place, but no mufflers, maybe the cat cons don't properly burn (they-cat cons- speed up the burning of hydrocarbons) the unburned hydrocarbons because they need the downstream restriction of the mufflers to burn correctly.

    You might not be able to run a modern engine-with sensors etc- without a muffler.

    PS A good muffler doesn't cost much power-in fact, straight pipes with no"chip" tuning might actually drop low end power while not increasing top end power.

    PPS-Did you ever see Thunder Road? Good movie with cars running open pipes.
  5. 22inSilverado

    22inSilverado New Member

    No it is y-ed into duals with 4 inch tips there are no mufflers on it what so ever and yes it is really loud. But the check engine and reduced engine power is not helping things what so ever!! =[
  6. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Is the catalytic converter also gone?

    If it is gone, then the electronic controls will be going haywire. The O2 sensors will be giving the ECM information that it can't make sense out of.

    Your best bet is to replace the cat con, and try it like that.

    Modern vehicles have all sorts of controls-yours is going into a limp home don't hurt itself mode because it thinks something is wrong because of the weird reading it is getting from the O2 sensors(if the cat is gone)

    If the cat is present, just the lacl of a muffler can make the cat not work correctly(a guess).

  7. 22inSilverado

    22inSilverado New Member

    No the cat is still there and it just started happening out of the blue i have had the exhaust for about 2 and a half years and it just started happening so i don't know if it just got worse over time or what.
  8. Rice

    Rice New Member

    Your neighbours probably poured sugar into your gas tank :glasses:

    Seriously, why would you want to run it w/o mufflers?

    I don't think that you will find a solution on the internet.
    I suggest to plug a diagnostic computer and get the codes. I'm sure there's got to be a whole bunch of them, like lean mixture, etc...
  9. 22inSilverado

    22inSilverado New Member

    I was a young dumb kid when i had the exhaust put on all i cared about was loud i also put on edelbrock headers on at the time so, I am looking to purchase a new exhaust system but wanna find out the problem that is at hand now with the reduced engine power.
  10. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    I woulod bet it is something simple-like a dead O2 sensor.They are common, and not too expensive. I think you can take it out-bring it to autozone-they will check it and tell you if it is dead.

    Make sure you get a code reader-borrow from Autozone- and read the codes 1st so you don't do a lot of un necessary work.

    You might find the cat con is dead-plugged-not too uncommon.

    Get-borrow the code reader- and it will tell you exactly(more or less) what is broken and why it is in a limp home mode.

    I wouldn't buy a whole new exhaust-just have someone plug a muffler into your straight pipes-A decent muffler shop can do that easily enough. Heck, it will probably improve your low end throttle response.


    PS- In 1975 I removed the prefectly good stock mufflers on my 1971 383 Cuda and replaced them with cheapo Thrush mufflers.Made lots of noise, and slowed me down a bit- Live and learn!

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