is it bad to adjust the throttle stop screw???
02-11-2004, 08:50 PM
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is it bad to adjust the throttle stop screw???
i had a problem with my TB - https://honda-tech.com/zerothread?id=741561 and it wasn't fix yet.
when i replaced my stock clutch with an exedy organic, i asked the mechanic to check and confirm if it's the throttle plate/pivot that's causing the problem. i also narrated to him what i've posted on the link above. indeed it was the throttle plate and he told me to have a machine shop rebore it but for a quick fix he went ahead and adjusted the throttle stop screw which the helms manual stated not to adjust it.
after adjusting it, the idling was a bit OK coz the throttle plate is closing more. i checked the TPS voltage on the VAFC and it reads 0.42V and 4.595 on WOT. i looked in the helms manual and the voltage should be at approx. 0.49V-0.5V and 4.5V at WOT.
i adjusted the throttle stop screw again to 0.485V but the WOT reading went to 4.605-4.610V. i tried backing it down to 0.42V but still 4.605-4.610V. again, i'm using the VAFC to read the voltage.
now, my questions are:
- since 4.605-4.610V at WOT is beyond the 4.5V of the TPS measurement of helms, will this cause any problem? if so, what will the problem be. btw, the car is turbocharged.
- why did helms recommend not to adjust the throttle stop screw? is it bcoz the TPS voltage might change? since the mechanic adjusted it already, will there be any problem?
any help will be appreciated.
when i replaced my stock clutch with an exedy organic, i asked the mechanic to check and confirm if it's the throttle plate/pivot that's causing the problem. i also narrated to him what i've posted on the link above. indeed it was the throttle plate and he told me to have a machine shop rebore it but for a quick fix he went ahead and adjusted the throttle stop screw which the helms manual stated not to adjust it.
after adjusting it, the idling was a bit OK coz the throttle plate is closing more. i checked the TPS voltage on the VAFC and it reads 0.42V and 4.595 on WOT. i looked in the helms manual and the voltage should be at approx. 0.49V-0.5V and 4.5V at WOT.
i adjusted the throttle stop screw again to 0.485V but the WOT reading went to 4.605-4.610V. i tried backing it down to 0.42V but still 4.605-4.610V. again, i'm using the VAFC to read the voltage.
now, my questions are:
- since 4.605-4.610V at WOT is beyond the 4.5V of the TPS measurement of helms, will this cause any problem? if so, what will the problem be. btw, the car is turbocharged.
- why did helms recommend not to adjust the throttle stop screw? is it bcoz the TPS voltage might change? since the mechanic adjusted it already, will there be any problem?
any help will be appreciated.
02-12-2004, 04:36 AM
#2
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Re: is it bad to adjust the throttle stop screw??? (_Endless_)
No worries on having the TPS voltage higher than 4.5v @ WOT...its alright. Having .42v - .48v @ idle is perfectly acceptable as well.
When you mess with the throttle stop screw, you are messing with the TPS output. Another purpose the screw serves is to not allow the plate to fully seat in the bore. Allowing that to happen would eventually round out the bore creating a continous vacuum leak.
This screw should not be adjusted when trying to set the idle...the idle air bypass screw is there for that purpose.
When you mess with the throttle stop screw, you are messing with the TPS output. Another purpose the screw serves is to not allow the plate to fully seat in the bore. Allowing that to happen would eventually round out the bore creating a continous vacuum leak.
This screw should not be adjusted when trying to set the idle...the idle air bypass screw is there for that purpose.
02-13-2004, 09:58 AM
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Re: is it bad to adjust the throttle stop screw??? (_Endless_)
Hmm.. Well first off, I'm not too familiar with how Honda works with its IAC so I'm going to assume that they're all the same.
You said your throttle plate was sticking so you cleaned it out. And after that you ended up with an erratic idle. Not knowing what vehicle you've got, I'm assuming you have an IAC. And what I also might assume is that the hole where the IAC pintle seats is dirty and thus could cause the a vacuum leak.
And then you said that you also pulled the PCM fuse, well as far as I know.. Pulling the PCM fuse is like unplugging the IAC. Therefore I assume your IAC needs to relearn where its zero count is. And to do this, you need a Scan Tool.
I know, not much help.. But good luck..
Oh and one thing. I'm pretty sure my instructor was said that you're not suppose to adjust the Throttle Plate setting. Adjusting that will screw up a lot of things.. Therefore your mechanic shouldn't have adjusted it to close more..
If I can't figure something out, I usually won't bring a car to a mechanic, I bring it to a technician..
You said your throttle plate was sticking so you cleaned it out. And after that you ended up with an erratic idle. Not knowing what vehicle you've got, I'm assuming you have an IAC. And what I also might assume is that the hole where the IAC pintle seats is dirty and thus could cause the a vacuum leak.
And then you said that you also pulled the PCM fuse, well as far as I know.. Pulling the PCM fuse is like unplugging the IAC. Therefore I assume your IAC needs to relearn where its zero count is. And to do this, you need a Scan Tool.
I know, not much help.. But good luck..
Oh and one thing. I'm pretty sure my instructor was said that you're not suppose to adjust the Throttle Plate setting. Adjusting that will screw up a lot of things.. Therefore your mechanic shouldn't have adjusted it to close more..
If I can't figure something out, I usually won't bring a car to a mechanic, I bring it to a technician..
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