ok car is automatic ...

when in park i get wacky jump from 500-1100 rpm.. that ive kinda fixed by the idle screw and other minor adjustments... used to be worst, but got it somewhat contained

when its in drive and/or at stop light or near stopping like under 10mph.. i get a jolt or hopping surge... idles from 500-1500 ish.. if i put it in netural or park.. it shoots up to 2500 and then down to idle at normal rpm...

only way i can adjust or effect this is, 80% of the time, i can turn on the AC and it will keep the idle in check and not move when sitting at red light or under 10mph.

question? can i have too much voltage? how can i fix this? I have tried to do the idle scew on the IM and i can pretty much turn it all the way closed and it dont effect the car at all...

like i have two modes.. in park and out of park....

 

What's this got to do with voltage?

Might be a sticky IAC valve? The ECM uses the IACV to hold idle steady whenever the load changes. Like using AC (the ECM knows when the compressor clutch is engaged); transmission (the ECM knows); or big changes in electrical load (ELD tells the ECM about that). Sometimes they're just dirty, but sometimes the IACV is just bad...

 

where is the IAC VALVE on a 93 si stock???? I have a ELD problem...everytime i turn something on the rpms drop really low then back up when i hit the gas!!!! could this be the same problem area?????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jazzy19 &raquo;</TD></TR><TR><TD CLASS="quote">where is the IAC VALVE on a 93 si stock???? I have a ELD problem...everytime i turn something on the rpms drop really low then back up when i hit the gas!!!! could this be the same problem area?????</TD></TR></TABLE>Somewhere on the throttle body & intake manifold. Get a repair book... or maybe check out the pictures at hondaautomotiveparts.com.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">What's this got to do with voltage?

Might be a sticky IAC valve? The ECM uses the IACV to hold idle steady whenever the load changes. Like using AC (the ECM knows when the compressor clutch is engaged); transmission (the ECM knows); or big changes in electrical load (ELD tells the ECM about that). Sometimes they're just dirty, but sometimes the IACV is just bad...
</TD></TR></TABLE>

just throwing out an idea.. i thought maybe that it was too high and when the ac came on it put it down within its proper range..

i just went and picked up another IAC and its nasty,... so i ll clean it up an see what happens..

 

I think the IACV needs to be open at least a little to idle. If you unplug it the rpm drops & maybe dies. Sounds like yours won't close all the way, so your idle is 'stuck' high. Well, some of this stuff probably depends on what year/model.

About the voltage business...
I'm really not sure what would happen if your overall system voltage were too high - anything might get flaky then. So what's your alternator or battery voltage doing when your idle is goofing up? The voltage regulator is SUPPOSED to control voltage even at redline... The alternator has no way of knowing whether you're driving 80mph or revving in neutral.