96 LT1, gm847 cam and 1.6rr valvetrain install, some input needed
07-31-2009, 01:44 PM
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96 LT1, gm847 cam and 1.6rr valvetrain install, some input needed Myself and a good friend installed an 847 cam, double roller chain, mezeire ewp, comp pro mag 1.6rr nsa with the guide plates, pushrods, k800 springs, new seals, retainers, etc recently. using tunercats he put a baseline on the car so it would idle on its own, now it's making a popping out the exhaust, its very noticeable under very light throttle, sounds like maybe every 5 or 6 rotations itll pop out the exhaust almost like a gunshot. its not a constant thing, will happen about every 8-10 seconds, under more throttle it goes away and anything above 2500rpm and it runs ok, but at idle and very low speeds it does it. anybody know what could be causing this, or would the computer just need some more tweaking done to it? in the last few months the car has had a new opti, new tr6 plugs gapped to .035, and new 02 sensors as well, so I know its none of those.
Also, the transmission (performabuilt level 1 with less than 4000 miles on it) will not hold first gear at all, if you take it up the rpm's slowly it will run out but as soon as you go wot, it shifts into second, even with the selector pulled all the way back, can this be fixed with tunercats or is there something that is starting to go bad in the transmission? I am by no means ******* performabuilt, I have had nothing but a great experience with them and this transmission has performed flawlessly through everything that i've given it.
Also, the transmission (performabuilt level 1 with less than 4000 miles on it) will not hold first gear at all, if you take it up the rpm's slowly it will run out but as soon as you go wot, it shifts into second, even with the selector pulled all the way back, can this be fixed with tunercats or is there something that is starting to go bad in the transmission? I am by no means ******* performabuilt, I have had nothing but a great experience with them and this transmission has performed flawlessly through everything that i've given it.
07-31-2009, 02:12 PM
#2
I would readjust the rr's with the engine running and see if that helps.
Any exhaust leaks or open headers? Open air getting to the front o2's will cause it to pop pretty bad.
A better tune will adjust the line pressure and shifting points of the trans. Don't beat on it too much until you get a real tune. Not to mention the car should run much smoother.
Any exhaust leaks or open headers? Open air getting to the front o2's will cause it to pop pretty bad.
A better tune will adjust the line pressure and shifting points of the trans. Don't beat on it too much until you get a real tune. Not to mention the car should run much smoother.
07-31-2009, 03:06 PM
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car has pacesetter lt's with their y pipe and a 3" single chamber muffler in place of the stock muffler, I'll pop the valve covers and see if anythings come loose. thanks!
the person who tweaked with the computer has many years working on these cars, so I am confident that with a little more time he can work out any bugs that are in it, was just concerned maybe there was something internal that would be making that popping sound.
the person who tweaked with the computer has many years working on these cars, so I am confident that with a little more time he can work out any bugs that are in it, was just concerned maybe there was something internal that would be making that popping sound.
07-31-2009, 03:34 PM
#4
I would readjust the rr's with the engine running and see if that helps.
Any exhaust leaks or open headers? Open air getting to the front o2's will cause it to pop pretty bad.
A better tune will adjust the line pressure and shifting points of the trans. Don't beat on it too much until you get a real tune. Not to mention the car should run much smoother.
Any exhaust leaks or open headers? Open air getting to the front o2's will cause it to pop pretty bad.
A better tune will adjust the line pressure and shifting points of the trans. Don't beat on it too much until you get a real tune. Not to mention the car should run much smoother.
07-31-2009, 06:05 PM
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rockers were all good, a couple had around zero lash, gave them about an 1/8th turn then sinched it back down, car seems to run a little better, still that horrible popping sound under 1500rpm, its not doing it under any throttle at all, just at idle or on decel, I wonder if I'm gonna have to live with this, or put a different muffler on it to try to quiet it down, I must be getting old my car seems obnoxious to me now!
07-31-2009, 06:06 PM
#6
rockers were all good, a couple had around zero lash, gave them about an 1/8th turn then sinched it back down, car seems to run a little better, still that horrible popping sound under 1500rpm, its not doing it under any throttle at all, just at idle or on decel, I wonder if I'm gonna have to live with this, or put a different muffler on it to try to quiet it down, I must be getting old my car seems obnoxious to me now!
