Idle problems/ IAC ??? - 95 GSI

[Andrew21]

Hey guys, Back in the Honda seen again, this time with a DC4 Integra, only a GSI but who knows what end up in that engine bay later down the track ;)

Picked up the car for a good price, its seems to be running ok except for a few things, hopefully some of you guys might have come across this before..

1. When you start the car COLD the revs hold right between 1500rpm and 2000rpm as the Cold start valve works ( like NORMAL ) however, usually after the car warms up after a few minutes the revs should drop to 900rpm or so...
THIS DOESNT HAPPEN, instead the revs stay constant at 1500rpm at idle even after almost 25mins of driving.

Now something which no doubt is linked to this, is that i noticed the temperture guage stays on cold for a long period 20min + ..... Sometimes the temp gauge will rise, revs drop to normal, then temp gauge drops back to cold and revs go higher again ??

Sounds to me like the IAC valve ?? ( think thats what its called ) ?
Or could it be a blocked Thermostat ? because seems to me the problem is the Car thinks the car is still cold hence why it increases the revs...

Any thoughts guys?

[1900-hustler]

dude have a look here at this thread

http://www.ozhonda.com/forum/showthread.php?t=8692

sounds like a thermostat problem.. it mite be stuck open.. thats why the temp stays cold wen ur moving.. get it checkd out

[aaronng]

A failed Honda thermostat fails in the open position. Get it replaced. There is a DIY here: http://www.ozhonda.com/forum/showthread.php?t=19092&highlight=thermostat

[Andrew21]

Awsome thanks boyz, sounds like the thermostat to me .. Will change this weekand and see how we go !!!

[Andrew21]

----UPDATE-----

Ok, changed the thermostat aswell as a service ( oil,plugs,coolant ) Also cleaned Throttle body out too. Half problems fixed now..

Now the temperature gauge reads property however the revs are still acting asif on cold start when the temp gauge is on normal.

They hold at 1500rpm and occassionaly will drop to 900rm and stay there until u turn the car off for a while and then goes back to cold start.

This must definately be the IAC valve now yeh ?

[tinkerbell]

or the idle screw is too far out (or missing!)

it is on the throttle body... screw it in to lower the idle...

(there is a proper way of setting it - but wotn describe the method until you are sure it is the problem...)

[Andrew21]

tinkerbell - i thought of what ur saying, but given the fact that the car drops to NORMAL revs ( 900rpm) every now and then, Lowering the Cold Ilde rpm would only be a band aid fix...but thanks for the thought...

[tinkerbell]

well, if you can describe the circumstances when it does idle properly (ie the now and then times), then that might help determin what causes the improper idle?

[aaronng]

----UPDATE-----

Ok, changed the thermostat aswell as a service ( oil,plugs,coolant ) Also cleaned Throttle body out too. Half problems fixed now..

Now the temperature gauge reads property however the revs are still acting asif on cold start when the temp gauge is on normal.

They hold at 1500rpm and occassionaly will drop to 900rm and stay there until u turn the car off for a while and then goes back to cold start.

This must definately be the IAC valve now yeh ?
Ever tried throttle body cleaner? There is a DIY on it here as well.

[bennjamin]

have u check the temp sensors on the block + thermostat ? Might be faulty...

(one is on the thermostat , and the other two are on the block , below the dizzy ~ )

[tinkerbell]

the sensor on the t.stat housing is a switch for the radiator fan, the single pin sensor under the dizzy is for the cluster temp gauge, and the two pin sensor under teh dizzy is for the ECU...

it is the 2 pin ECT sensor that you want to ensure is OK...

BTW - any ECU codes? it usually will tell you if the ECT sensor is not functioning properly...

[Andrew21]

Already cleaned the throttle body out man.. It was dirty, but didnt notice any changes...

Once the car is really warm is the only thing i notice when it idles normal.. other than than all other charastics are the same ? The sensors seem ok ( radiator fan comes on ok ) but i will double check the ECU sensor.. Also im gonna try a ECU test and see what it tells me.. Im going to try a mates IACV seeing as its very easy to replace , i suppose im going through the process of elimination !