Idle issue

[jtgh]

l drop 200 rpms for a while

drop from 800 to 600
or
go to 200 absolute?

[JMT]

Further to the problem had dealter check codes was advised none but took it back and had them check again. Said there was a pending code for the idle control valve. If its pending does that mean the electrical component of the valve is weak or is it something that can be cleaned?

[jtgh]

pending means its fail at least 1 time.
and with it fails often enough , CEL ON, DTC stored.

another word is soft failure. it is bad, just intermittant.


clean it, for sure.

[JMT]

Cleaned the idle control valve without success. If the valve is unplugged while engine running should there be a noticeable difference in idle when cold or hot?

[jtgh]

be sure to calibrate TPS to 1.5vdc , keyon, engine off.


this car has a single TPS (not ganged, no switch).
one sets it for 1.5v at the wiper pin.

if the voltage fails to reach 1.5v the ECU may not enter Idle mode.

if you can eaisly raise throttle with your right foot and get idle back up to 800
then mostlikely the EGR is not leaking,
if on the other and , this action seems difficult then the EGR is leaking.

Pending ISC , could be just :
that the ecu could not see RPM rise when it commanded it to rise.
or
i cold mean, it expects idle , even though it is currently disabled.


the TPS has 3 terminals.

1 = gray/yell >> ground.
2= gray >>>>> wiper , calib pin.
3=gray/red >>> power from ecu.


key on, measure voltage from pin 1 to 2. must be 1.5v.
using back probing technique, can not be unplugged to do this.


this is #1 setup for idle on 1.8L.


possibles.
1: TPS out of cal. Or bad TPS.
2: ISC ticking.
3: EGR leaking.
4: motor very sick ( low compression, slipped chain (gross noise) , stuck valves , etc)

[JMT]

Checked the TPS and adjusted. CLeaned the Idle Control Valve but have a really stupid question. Should I be able to move the spring/value open and closed - it appears to be seized in the closed position??

[jtgh]

this is a sport.
1.8L

TPS is set by voltage calibrated method.
EGR is stepper motor and quite diff.
ISC is motor driven. quite diff.

im no expert at cleaning them ,this type. i read how others do it, they just flush it with carb cleaner then while full ,of cleaner, , KEY ON no start, and plug in the connector and hope it will free, repeat connections over and over till clean.
try looking at it while helper keys on , no start, and see if it cycles.
Physically unmounted and connected electrically. looking in hole.

The Dealer has an exercise page in there scanner that allows them to flex the unit and make sure it works but we dont have that.

those are my bag of tricks, i had help from others to learn this.

all the best , jerry

[jtgh]

i could be stuck.
sometimes one can take a pop cicle stick , split it.
and use this to tickle the insides , flex it and use cleaner.
this can be amazing what can be done. just take it easy.

they are all expensive so it motivates one. cheer.s