x1 cam tuning...wont idle at startup....
09-09-2003, 03:48 AM
#1
x1 cam tuning...wont idle at startup.... I out in an x1 cam...and got tuned by mark at raging motorsports....
but the dam thing wont start up...hot or cold...I have to give it a bunch of gas for a about 30 seconds or so till it decides to idle...
I know this isnt normal
...what can I do to fix it....
and should he have fixed the part throttle air/fuel and timing as well??? we also drilled the throttle body plate just a little...not much....just a little...
anybody have any ideas???
I know bigger cams are having no problems...
but the dam thing wont start up...hot or cold...I have to give it a bunch of gas for a about 30 seconds or so till it decides to idle...
I know this isnt normal
...what can I do to fix it....and should he have fixed the part throttle air/fuel and timing as well??? we also drilled the throttle body plate just a little...not much....just a little...
anybody have any ideas???
I know bigger cams are having no problems...
09-09-2003, 08:54 AM
#2
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Re: x1 cam tuning...wont idle at startup.... do you have autotap or EFILive? did you check your IACs? Sounds like it hunting for an idle and the tb needs to be drilled a little more
09-09-2003, 09:27 AM
#3
Re: x1 cam tuning...wont idle at startup.... Hate to say this, but I think that is pretty normal. After you have driven it around for a couple hundred miles it will get better (PCM learning,) but I doubt anybody has a perfect cold idle for the first few seconds to a minute with an aftermarket cam. The bigger the cam the worse it is. There are a few things you can do with LS1edit to make it better though. I don't know what Raging Motorsports did to tune your PCM, but it sounds like your VE is still too high. With a cam that size you probably need a full 0.250 inch hole in the TB if you are drilling out the existing hole. Also, I'd bump up the idle speed to 950, and add another 5 degrees of timing. Maxing out the Decay for low speeds will help a lot to make the idle more stable (less surging.)
09-09-2003, 09:43 AM
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Re: x1 cam tuning...wont idle at startup.... Your curve looks like the part throttle stuff was ignored. Your stock tune + that cam would act like you are describing. Only tuning for WOT is lazy and misguided- you're going to spend a lot more time at partial in a daily driver, plus that part needs to biuld on the part throttle tweaks.
Initial startup until the O2s get warm uses a different table that needs to be addressed. If you did a baseline, then tuned some, then another pull etc it might never have gotten cool enough to start using these, or to use them very long. Overnight it cooled enough to show you what a sloppy tune it was- no start is predictable if these were ignored.
Initial startup until the O2s get warm uses a different table that needs to be addressed. If you did a baseline, then tuned some, then another pull etc it might never have gotten cool enough to start using these, or to use them very long. Overnight it cooled enough to show you what a sloppy tune it was- no start is predictable if these were ignored.
09-09-2003, 10:15 AM
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Re: x1 cam tuning...wont idle at startup....
Your curve looks like the part throttle stuff was ignored. Your stock tune + that cam would act like you are describing. Only tuning for WOT is lazy and misguided- you're going to spend a lot more time at partial in a daily driver, plus that part needs to biuld on the part throttle tweaks.
09-09-2003, 10:56 AM
#6
Re: x1 cam tuning...wont idle at startup.... well i think it would be funny if mark went PART THROTTLE ON THE DYNO...that would be HELLA power if it were only part throttle. i am pretty damn sure it was floored as hard as possible on the dyno rollers. megathumpzilla, check yourself and go part throttle your denz.com *** hehehe.
seriously, that idle should not be like that. IACs are off. no biggie. go back to mark, drill out the TB hole a bit to get it back into range and read it on a scanner (autotap, etc, etc).
i have a 230/230 .573" 111 lsa in my automatic (much harder to idle) and it idles pretty damn well. i just had to do some work here and there to get her just right. good luck and go have mark work on it again. you will be just fine.
seriously, that idle should not be like that. IACs are off. no biggie. go back to mark, drill out the TB hole a bit to get it back into range and read it on a scanner (autotap, etc, etc).
i have a 230/230 .573" 111 lsa in my automatic (much harder to idle) and it idles pretty damn well. i just had to do some work here and there to get her just right. good luck and go have mark work on it again. you will be just fine.
09-09-2003, 01:50 PM
#7
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Re: x1 cam tuning...wont idle at startup....
Hate to say this, but I think that is pretty normal. After you have driven it around for a couple hundred miles it will get better (PCM learning,) but I doubt anybody has a perfect cold idle for the first few seconds to a minute with an aftermarket cam. The bigger the cam the worse it is. There are a few things you can do with LS1edit to make it better though. I don't know what Raging Motorsports did to tune your PCM, but it sounds like your VE is still too high. With a cam that size you probably need a full 0.250 inch hole in the TB if you are drilling out the existing hole. Also, I'd bump up the idle speed to 950, and add another 5 degrees of timing. Maxing out the Decay for low speeds will help a lot to make the idle more stable (less surging.)
Whats this "DECAY" you speak of???
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09-09-2003, 07:37 PM
#8
Re: x1 cam tuning...wont idle at startup.... Under Idle+Limiters, there is a "Airflow Decay In Gear" table, also known as "Throttle follower Decay." I just filled all cells from 0 to 14 mph with 31's, almost the max value you can put in there. That really helps to get a stable idle that isn't bouncing up and down all the time. Bouncing up is irritating, but bouncing low can make the engine die. Oh and you might want to jack up the P/N Decay also.
As it was explained to me, this value is an inverse gain function for a closed loop feedback amplifier, for those that have studied control systems. For those that haven't, the stock value with a big cam is like a kid trying to learn to drive and swerving all over the road because he is over compensating.
As it was explained to me, this value is an inverse gain function for a closed loop feedback amplifier, for those that have studied control systems. For those that haven't, the stock value with a big cam is like a kid trying to learn to drive and swerving all over the road because he is over compensating.
09-09-2003, 11:19 PM
#10
Re: x1 cam tuning...wont idle at startup.... Here is an excellent thread on decay. Cal and NoGo really understand this ****. NoGo is The MAN, 
Very educational- they've been a BIG help to me.
idle issues
joel
Very educational- they've been a BIG help to me.idle issues
joel
09-10-2003, 12:34 AM
#12
Re: x1 cam tuning...wont idle at startup....
good **** by the time i finish with this forum i will be proficient in LS! edit and tuning
and I found out that new things were being discovered everyday, so you never know it all. But mostly this board has been a huge help. You might want to get on the LS1edit email list forum also if you like tuning.