I just got my 93 prelude si 4 months ago and after changing the oil, spark plugs, and fuel filter i get a rough idle when it's cold

 

Try doing a valve adjustment

 

thanks i'll check that out

 

could you explain your car's symptoms better than rough idle at cold start?

So while its warming up from cold start the idle bounces all over? or It chugs / sputters? any other info you can provide would help us help you

 

when cold the car is running rough around 500 to 800 rpm and it sputters
if i give it a quick step on it (like i wanna rev it up) the engine starts to bog out into lower rpms
if i give it jus the righ amount of acceleration it then starts to rev
i have to give it jus a bit and slowly advance from there

 

also sometimes around that 500 to 800 rpm the engine vibrates excessively

once its warmed the car runs normal

 

sounds like FITV

 

Plus 1<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vlang29 &raquo;</TD></TR><TR><TD CLASS="quote">sounds like FITV</TD></TR></TABLE>

 

is the fast idle thermal valve located below the throttle body?

and if so what vaccumes connect to it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robzilla0589 &raquo;</TD></TR><TR><TD CLASS="quote">is the fast idle thermal valve located below the throttle body?

and if so what vaccumes connect to it</TD></TR></TABLE>

yep, bolts right to the bottom.

No vacuum lines, the hoses going to the FITV are coolant.

 

what part do the coolant lines come of

because there are no lines connected to this valve

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robzilla0589 &raquo;</TD></TR><TR><TD CLASS="quote"> no lines connected to this valve</TD></TR></TABLE>

that could be your problem. the coolant lines come from thermostat housing, goes through FITV, then through IACV, then back to the thermostat housing.

 

hella yea

imma route thoes lines tomorrow and post results later that night

thanks bro

 

not 100% sure if it matters, but the nipple on the top of the thermostat goes to the FITV first, then though the IACV, then to the nipple on the side of the thermostat

 

it probably does but thats the way i put it anyway because of the flow of the coolant

anywayz it seems to have worked some what wit the power loss i was having in high rpms
and my engine came to a steady idle quicker than normal

 

have you tried re-setting the ECU? sometimes that works wonders for idle issues

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vlang29 &raquo;</TD></TR><TR><TD CLASS="quote">sounds like FITV</TD></TR></TABLE>

What?!?!?

The FITV being bad would cause an idle SPEED problem, too much or not enough air.

If the car is sputtering and such, you have other problems. If you have no coolant going to the IACV, it could be getting frozen (or partially) in the cold and not able to do its job, which could be the rough idle problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">

What?!?!?

The FITV being bad would cause an idle SPEED problem, too much or not enough air.

If the car is sputtering and such, you have other problems. If you have no coolant going to the IACV, it could be getting frozen (or partially) in the cold and not able to do its job, which could be the rough idle problem.</TD></TR></TABLE>


he did have an idle speed problem, he said on cold start it was only running 500-800.

 

750 +/-50rpm is the correct idle speed

Which falls in that range.

 

when warm yes, but not cold.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robzilla0589 &raquo;</TD></TR><TR><TD CLASS="quote">when cold the car is running rough around 500 to 800 rpm </TD></TR></TABLE>

 

Vlang is correct


Modified by Acidcrakker at 1:07 PM 1/5/2008

 

who has been pawned? am i wrong that a car should idle faster than 750 on a cold start?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vlang29 &raquo;</TD></TR><TR><TD CLASS="quote">who has been pawned? am i wrong that a car should idle faster than 750 on a cold start?</TD></TR></TABLE>

No, you're right (nobody got pwned ). Fast idle should be closer to 1000+ than 750 from every car I've ever seen.

 

OP dont forget the Fast Idol Screw on the TB

 

My car idles at about 12-1500 rpms untill it warms up a bit,then drops to about 750-800 rpms at idle.Also it runs about 100 rpms lower if I have all my accesories going....radar detector,heater on blast and head unit pumping....is this normal?