Having idle issues with new ported TB
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TECH Apprentice
Joined: Nov 2001
Posts: 350
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From: Lexington, SC
Having idle issues with new ported TB I bought a ported TB from a highly recommended sponsor and the TB looks pretty good. Anyway, I reset the computer twice and did the idle relearn procedure 3 times and it didn't seem to
help. Sometimes when I first start the car the idle is about 300-400 rpm too high, but it drops down to normal within about 15 seconds (800). It usually only starts around 200 too high and then drops to normal (800). Another problem is that when I'm driving around and push the clutch in the rpm stays around 600-800 rpm above idle for awhile and then drops down to about 100rpm above normal idle (before the ported TB it would drop straight to idle). Then when I come to a complete stop in neutral and the idle settles down the rpms will surge from 900-1000rpm (normal idle is 750-800). Also, if it sits at idle for a few minutes it will surge to 1400rpm for about 4 seconds every minute or so and then resume it's normal 900-1000rpm surging. Very strange. Has anyone had a problem like this? Seems like most people don't have idle problems with these types of ported TBs. Usually when I reset my computer (I always pull the fuses) my idle will be a little funny for a day, maybe two, but it doesn't act like this. The car has had over 3 days and about 60 miles worth of relearning time but it's not getting any better. I have been in contact with the manufacturer of this TB as well, but so far the ideas he's given me I've already tried. I still have the stock cam. The rest of my mods are listed here: http://www.geocities.com/jsramair/Car/main.html Thanks for any help.
help. Sometimes when I first start the car the idle is about 300-400 rpm too high, but it drops down to normal within about 15 seconds (800). It usually only starts around 200 too high and then drops to normal (800). Another problem is that when I'm driving around and push the clutch in the rpm stays around 600-800 rpm above idle for awhile and then drops down to about 100rpm above normal idle (before the ported TB it would drop straight to idle). Then when I come to a complete stop in neutral and the idle settles down the rpms will surge from 900-1000rpm (normal idle is 750-800). Also, if it sits at idle for a few minutes it will surge to 1400rpm for about 4 seconds every minute or so and then resume it's normal 900-1000rpm surging. Very strange. Has anyone had a problem like this? Seems like most people don't have idle problems with these types of ported TBs. Usually when I reset my computer (I always pull the fuses) my idle will be a little funny for a day, maybe two, but it doesn't act like this. The car has had over 3 days and about 60 miles worth of relearning time but it's not getting any better. I have been in contact with the manufacturer of this TB as well, but so far the ideas he's given me I've already tried. I still have the stock cam. The rest of my mods are listed here: http://www.geocities.com/jsramair/Car/main.html Thanks for any help.
Re: Having idle issues with new ported TB I home ported my own, and had no call to
do all of that idle relearn crap.
You should never drill that hole unless
your IAC isn't capable of maintaining a
> high enough < idle. Right out of the box?
Don't screw with it.
That kind of sllooowwww settling I think
sounds like either a wimp return spring
or sticky cables, or throttle blade drag.
You can reseat the blade - loosen the screws
slightly, open & let is snap closed a couple
of times, tighten while closed. If it
doesn't snap like a mousetrap, move on to
the cables; lube, not -too- snug, leave
1/8" of free play - and the spring; good
pound or two of open tension at WOT, and
at least maybe 1/2 lb at closed? If not,
might want to wrap it around one more time.
If you can't, it's tight enough.
IAC motor - try swapping on your original,
if it worked well. Maybe the one that came
with the core that's now a shiny powder
coated TB, isn't so shiny underneath.
Got to wonder, until you know. If you don't
have one to try, they probably aren't that
expensive. But check the mechanical, free
stuff first.
do all of that idle relearn crap.
You should never drill that hole unless
your IAC isn't capable of maintaining a
> high enough < idle. Right out of the box?
Don't screw with it.
That kind of sllooowwww settling I think
sounds like either a wimp return spring
or sticky cables, or throttle blade drag.
You can reseat the blade - loosen the screws
slightly, open & let is snap closed a couple
of times, tighten while closed. If it
doesn't snap like a mousetrap, move on to
the cables; lube, not -too- snug, leave
1/8" of free play - and the spring; good
pound or two of open tension at WOT, and
at least maybe 1/2 lb at closed? If not,
might want to wrap it around one more time.
If you can't, it's tight enough.
IAC motor - try swapping on your original,
if it worked well. Maybe the one that came
with the core that's now a shiny powder
coated TB, isn't so shiny underneath.
Got to wonder, until you know. If you don't
have one to try, they probably aren't that
expensive. But check the mechanical, free
stuff first.
Re: Having idle issues with new ported TB The TB Air bypass may not be big enough. I know when I had my motor work done my car would idle like ****. But then they drilld out a slightly bger hole in the TB buterfly valve [the TB Air Bypass] and the car resumed its normal idle.
Might be somethin to look into maybe?
Might be somethin to look into maybe?
Re: Having idle issues with new ported TB Either too much air is getting passed the throttle blade and/or the idle screw is too high, or the IAC sensor is bad.
<small>[ February 07, 2003, 01:51 AM: Message edited by: Jantzer98SS ]</small>
<small>[ February 07, 2003, 01:51 AM: Message edited by: Jantzer98SS ]</small>
