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problem after installing ported throttle body

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Old Oct 22, 2005 | 11:25 PM
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From: Leon Iowa
Default problem after installing ported throttle body

When I start it it will rev to about 2500 then drop to 900 fast and sometimes almost die. It does the same thing when I put it in gear. After it has run for a bit all is fine. Anybody have any ideas?
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Old Oct 22, 2005 | 11:50 PM
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From: Sterling VA
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If u did the epoxy part of the mod, then make sure the holes are drilled big enough. If not, I'd look into seeing whether or not it was ported too close to the TB blade. There's a certain part where you're not supposed to port past. Maybe the blade got sanded too much if you sharpened the edge of the TB blade. Hold it up to the light to see if there are any gaps around the perimeter of the blade to see if there are any air leaks.

Those are all the things that I can think of off of the top of my head. I had a similiar problem that worked itself out after a few back to back startups. If u haven't tried already, start it up a few times and let it find the idle and then shut it off and repeat till it idles fine. It took me 3 times, but could take a few more if u ported the hell out of it.
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Old Oct 23, 2005 | 08:06 AM
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From: Little Rhody
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I had the same problem. You either have to modify the blade angle in the PCM for cold start (this is something I was told) or get another one. Sorry, but in the end I got a second one as the first one I had was too aggressively ported for my car. It turned out the throttle body was very porous and during the porting process he had to go a little larger to get rid of the pits.

Who ported it?
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Old Oct 23, 2005 | 10:24 AM
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TB was ported improperly....You have too large an airgap around the blade in its "rest" closed position (hence the reason it flares up immediatly on fire-up). You might be able to adjust it on an F-Body but would be SOL if it were a Y-body (C5).

Good luck...
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Old Oct 23, 2005 | 01:42 PM
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From: Leon Iowa
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Well I put it back on after I bent the tab by the spring and it works perfect. Idles great and everything. I thought I might have to go a little further but after it warmed up it was fine. When I first started it when it was cold it reved to about 1300 and then came back down. Hell of a lot better than 2500. Thanks alot for all the help.
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Old Oct 23, 2005 | 04:58 PM
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From: Leon Iowa
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I thought I would do a little bit more adjusting so I removed it again. The person that ported it weny too far and the blade had alot more gap in it than my stock one therefor giving it alot more air at idle. I messed around with it till 3:30 in the morning and finally figured out how to fix it. The blade needed to be closed more but there was no adjustment. So I made adjustment. I had to grind one spot on the throttle body where a spring sets to let the spring set in more to take up extra slack after doing the next step. Then there is a stop on the shaft that had to be bent more to let the blade close more. I was comparing the gaps in the blade with my stock one so I could get it right. I think I had it apart 5 times doing adjustments. It gave it alot more mid and top end power. I'd say it's the biggest HP gain mod I have done. I can feel a good HP increase.
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