throttle body drilling
02-09-2007, 12:47 PM
#1
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throttle body drilling hey guys, the previous owner of my 1999 SS camaro had put H/C on it. The PCM was then tuned for that setup. He then took that cam out and put a bigger one in. the PCM was never tuned for this cam that is still currently in there. on a cold start if i dont give it gas and keep it between 500-1000 rpm it will stall. once the temp gauge reaches a little over 100* it idles perfect at 750rpm. I know that if i drill a bigger hole in the throttle body it should help my car idle. So my question is will drilling the hole bigger throw the idle off when the car is warmed up? thanks in advance
02-09-2007, 12:54 PM
#2
It will probably warm idle the same if you drill the hole a bit, because the IAC will just close up a bit more. This isn't really the right way to fix it ya know. 
Besides, you drilling the hole may not even fix the problem. Also, with the bigger cam, the car is probably going lean on the top end, which needs to be fixed too. How much bigger was the cam?
Besides, you drilling the hole may not even fix the problem. Also, with the bigger cam, the car is probably going lean on the top end, which needs to be fixed too. How much bigger was the cam?
02-09-2007, 01:16 PM
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yea i know its not the right way but i dont have the cash to get it tuned right now. i have absolutly no idea how big the old cam was. the current cam is a TSP 233/239, and i have actually read about people haveing a problem with this cam on a cold start. i just want to thank you for always helping and answering my questons so quick. thanks man. will drilling this hole mess anything up in the long run?
02-09-2007, 01:27 PM
#4
Originally Posted by TheLS1Kid
yea i know its not the right way but i dont have the cash to get it tuned right now. i have absolutly no idea how big the old cam was. the current cam is a TSP 233/239, and i have actually read about people haveing a problem with this cam on a cold start. i just want to thank you for always helping and answering my questons so quick. thanks man. will drilling this hole mess anything up in the long run?
02-09-2007, 01:31 PM
#6
If it idles fine warm now, then chances are after you drill the throttle body you may have the "cruise control" effect and a hanging idle. Drilling the TB is a poor substitute for tuning. Do a search on "cracker" in the PCM forum and you'll find a ton of threads with helpful info. Here's an example: https://ls1tech.com/forums/pcm-diagnostics-tuning/566565-idle-air-throttle-follower-throttle-cracker.html
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02-09-2007, 04:10 PM
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im just going to drill another hole in it, start small and work my way up to where it doesnt surge anymore. this subject is so opinionated so there is really no WRONG way. thanks again for all the help guys.
02-09-2007, 08:57 PM
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just save up and get it tuned.... drilling the hole is only going to make things worse!! i drilled my tb hole when i had a hotcam untuned, and it just ran even worse!! the car would like drive itself and accelerate on its own, i didnt even have to press the gas!!
02-10-2007, 08:57 AM
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Do not drill bigger than 3/32 hole.
I drilled mine to a 1/4 and rpms would hang up high when slowing down.
This was befor the magic of ls1 edit
Do a tune if anyway possible.
I drilled mine to a 1/4 and rpms would hang up high when slowing down.
This was befor the magic of ls1 edit
Do a tune if anyway possible.
02-10-2007, 09:46 AM
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i read on a old thread on here that it is better to drill a second hole rather than making the original one bigger, is this true? when i did a search i saw that when people do this it is because their car wont idle anytime. i just need to get mine to idle when cold. like i said earlier it is perfect once it warms up. thanks for the replies guys.
02-10-2007, 10:33 AM
#14
Originally Posted by 2xLS1
Some other thoughts about the TB hole.
https://ls1tech.com/forums/showthread.php?t=440075
http://www.hptuners.com/forum/showth...8974#post28974
https://ls1tech.com/forums/showthread.php?t=440075
http://www.hptuners.com/forum/showth...8974#post28974
you drilled mine 2 years ago.
02-10-2007, 11:52 AM
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yea good point. i didnt even think of that. one last question for you. did you drill the existing hole bigger or drill a second one? thanks man
02-10-2007, 03:55 PM
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I bought an LS1 pullout and it had an enlarged hole in the throttle plate. Somebody please tell where I can get a stock replacement. Even after dyno, I can't get the idle down where I want it and the engine won't come right down to idle after revving. It hangs out at 1500 for a few seconds before the IAC an adjust.