Basic Tuning Question!

[Livn2sk8]

Ok...I was wondering if someone had a post up, or if someone knows where I can find an easy way to basically smooth out my idle.

My idle sucks....basically at first start up....once it's warmed up, it's a little better.

my basic question is this....you have the base idle set screw (BISS) and you have that one sensor on the TB (TPS I think) ....I haven't messed with the BISS...but what's a good way, to insure a proper a/f ratio and still get a smooth idle, and where do I put the BISS? all the way in? and where does that TPS (throttle plate position sensor) sit? all the way clockwise? counter clockwise? in the center? it's positionable..so I dunno...anyways...any ideas or help is appreciated....and no...I don't have a S-afc

[peanotation]

when i had rough idles i knocked the rpms up about 100 via the little screw that directly adjusts the TB butterfly wheel. what does your car idle at as soon as you turn it on before it starts fluctuating? mitsu says to use 750rpms +/-100rpm. my idle is actually 1,100 when i'm in neutral/park :? when i'm stopped in gear its about 800. when i get the 5spd in i'll re-adjust it lower. but you have a 5spd already so ignore that last part

[Livn2sk8]

Mine is about 1000rpm at all times...but when I cold start it...it's anywhere from 500rpm to 1000rpm....it doesn't "fluctuate" too much...as far as the needle jumping around...but it's never a consistent idle...until it warms up

[peanotation]

yeah, i used to have the same problem. inspect your TB and clean it if neccessary. i dont know what to say, lol. i'll check the service manual trouble shooting section. how long do you let it warm up for?

edit: it doesn't have a trouble shooting section for idle, but it instructs the mechanic to wait 2 minutes before reading or adjusting the idle. sounds like it wants you to ignore anything before it's warmed up.

[Livn2sk8]

ok...I just didn't know if there was a sensor, or something that might be bad...something that adjusts the idle during cold starts.....and yes..my TB is clean....

[brandon]

The only way to check the TPS is with a logger... I wouldn't recommend trying to adjust it unless you have one.

[JiP]

peano you silly bastard. That screw opens the throttle plate. Your kinda just wastin gas lol. Why didn't you just open the BISS up a bit?

I don't have an ISC/IAC so my idle is all set by the BISS. I idle around 850 in gear, 1200 in P/N when fully warmed up. I vibrate at 850 a lil, if I raise the idle up to 1k its so much smoother...but vibrations dont bother me much although I noticed that the vibrations in my car actualy turn the BISS. After a while my idle would drop from 850 to stalling zone...I realized after the third or fourth time of adjusting the BISS that it was actually screwing itself closed from the cars vibrations...so I put some tape around the threads so it was a real tight fit and havent had a problem since.

[peanotation]

well, i've sat there with a screwdriver and turned my BISS all the way clockwise and counterclockwise, and it doesn't do anything. it's hella wierd, i know. but i told him to adjust the throttle plate screw because it'll do just that: adjust your idle. i've had to adjust mine, and just a little turn of the screw can bring you up or down 50rpms

[JiP]

Ye it will obviously raise your idle its the same thing as if you kept your foot lightly on the gas thats all your doin there..

In your cars with IAC/ISC the BISS will only adjust +-150rpm abouts..