Lacking power from 0-20(1st gear) LT1 need help - Page 2
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5.0 and 5.7 Discussion, Lacking power from 0-20(1st gear) LT1 need help in Cadillac Engine Technical Discussion; Originally Posted by N0DIH You don't have a stuck PCV valve or something do you? It would make it doggy ...
  1. #16
    ocjmakaveli's Avatar
    ocjmakaveli is offline Cadillac Owners Enthusiast
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    Re: Lacking power from 0-20(1st gear) LT1 need help

    Quote Originally Posted by N0DIH
    You don't have a stuck PCV valve or something do you? It would make it doggy until you get going. The ECM would be showing a way off long term fuel correction, and once long term gets set, short term should get back around 128. But it will be fluxating much more wildly than with no vacuum leak.

    Sounds like something got put together wrong, connected wrong, or is leaking.

    Fuel pressure regulator do anything like this? (I can't imagine it would, but...)

    I haven't read up on the flow charts on the 4L60E, but on the THM350/400 manual shift does increase fluid pressures across the board. The flow circuits change a but.
    I'm still waiting until i get the exhaust bolt back on right now i have the car torn apart with the exhaust bolts removed I just needed to order a right angle drill so im waiting for it because sears has them for 99.00 and I don't want to spend so much for a drill that will get hardly used.

    I'm also upgrading to grade 8 OEM exhaust bolts I bought from ebay so that I won't have this problem again. I should be done by friday or sooner.

    As soon as im able to get this bolt removed i'll put it back together and see if this fixes my problem or else ill invest in a the akm cable so that i can plug my laptop into the car and see the details of my cars pcm etc.

    The only other strange thing is lately i get a strong fuel smell just from backing into the garage which takes maybe 10 seconds at most and then the garage smells horrible for a couple minutes which didn't happen before could the exhaust leak cause this?

    by either leaking exhaust or by causing an incorrect adjustment by the o2 sensor causing too much fuel too be burned?

    the way my car behaves well most of the time is when i step about 1/4 of the gas down its ok but anything harder it won't react like it used too or is supposed too it just acts like if i am only steppng about 1/4 down on the pedal.

  2. #17
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    N0DIH is offline Cadillac Owners Master
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    Re: Lacking power from 0-20(1st gear) LT1 need help

    I wonder if the knock sensor is "seeing" the noise from the leak and pulling back timing. Else I can't se how an exhaust leak could ever hurt performance. The Opti treats the LT1 as 8 1cyl engines, so if it sees the leak as a knock on one cyl, it will pull that one cyl back for sure.

    If....

    I guess you can pull the 2 knock sensors and drive and see how it does. If power returns, that is the problem. Or can you simply remove the knock sensor module in the ECM?

  3. #18
    ocjmakaveli's Avatar
    ocjmakaveli is offline Cadillac Owners Enthusiast
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    Re: Lacking power from 0-20(1st gear) LT1 need help

    i forgot to mention my pvc valve is about 18 months old and has less than 5000 miles on it could it still be bad?

    there are a couple thing i read about exhaust leaks and here they are

    "This may help: I had a passender side manifold leak that progressed to the point that it was sucking in enough fresh air that the O2 sensors sensed a lean condition, so the PCM richened the right bank to the point that the car ran like you describe. It wasn't the rough running that concerned me the most, but when you push that much unburned fuel through catalitic converters they plug up pretty quick.
    "

    thats what seems to be happening to my car this is why lately i am smelling such a strong fuel odor.

    I'm beginning to think that I broke this bolt around the same time i did my intake manifold job along with the main rear seal because I also did the engine oil pan gasket and i had to lift the engine so i used the exhaust manifolds and wrapped a chain around them this may have caused the bolt to snap on the pass side.

    I remember a few days after i was done i was checking the engine and htat when i noticed the alt bracket to manifold bolt was dangling so I am pretty sure this is the culprit because it all started after that time.

    I suggest checking your exhaust bolts guys this a very common problem and the originals are grade 5 and there was a GM TSB suggesting to upgrade to grade 8 to avoid breakage problems.

    on another note I just found out the vacuum should be between 15-22 I just ordered a gauge and should have it by friday.

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