What cause erratic idling before engine is fullly warmed-up?

Anyone has opinion what would cause the erratic idling before the
engine reaches
to a normal temperature? AFter the engine is fully warmed-up to normal
temperature, the erratic idling is gone. The erratic idle only occurs
during warm-up. I've heard something about
oxygen sensor taking over (controlling) something after an engine fully
warmed-up.

 

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On Hondas one of the easiest things to look for is low coolant level.
The rad has to be full to the very top, and the reservoir and (as an
experiment) fill the reservoir to the MAX mark. Check it again next
morning to see if it's missing some. If there's air in the system it
will sip what it needs each time the engine cools, assuming the rad cap
is working correctly. Many Hondas have an air purge nipple somewhere in
the system. The heater core can trap some air too, so be sure to turn up
the heat if you're trying to get air out. The presence of air in the
system will give false readings to the computer because the temp sensors
have to be immersed to work correctly, and if they aren't reading the
coolant's temp correctly, the computer mis-adjusts things like ignition
timing and fuel/air mixture.

'Curly'

'Curly'

 

What model and year of Honda we talking about here? How many
miles on it?

What Curly said may solve the problem. I tend to urge doing
a complete air purge, per the manual.

One other possibility is a failing Idle Air Control Valve
(or similarly named, e.g. EACV). That comes up here now and
then.

How old is your oxygen sensor, anyway?

 

89 civic with 220K miles on it.

I think my best guess I've found out it that the Coolant temperature
sensor
could be the problem. Where is the Coolant temp sensor in my car?
The manual has no picture on it.

what about Throttle Angle Sensor or Intake Air temperature sensor
beside EACV?


Is Curly saying that driving the car with turn the heater on would
purge the air out?

My oxygen senor is about 4 years old!.

 

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If there is air in the heater core, you may be able to get things back
to normal by filling the rad and reservoir with Honda premix, drive it
with the heater on, and see how much coolant it 'sips' from the
reservoir overnight. Top up again and see if it keeps sucking it up next
time it's cool.

Instead of labeling the reservoir MAX and LOW, Honda should have labeled
it MAX and WAY TOO LOW.

On an '89, try bleeding it from the purge nipple, but make sure you get
the majority of it out as I've described, since you can't remove AIR if
there's no coolant to displace it.

'Curly'

 

Part #24 at
http://www.hondaautomotiveparts.com/auto/jsp/mws/prddisplay.jsp?inputstate=5&catcgry1=Civic&catcgry2=1989&catcgry3=4DR+LX&catcgry4=KA5MT&catcgry5=ENGINE+SUB+CORD-CLAMP

See also the drawing at
http://media.honda.co.uk/car/owner/media/manuals/CRXManual/62SH200/5-56.pdf

Should be the same for your 89 Civic.

The idle troubleshooting chart in my Chilton's manual for
your 89 Civic says the coolant temperature sensor (a.k.a.
"TW sensor") is the most likely cause. This chart appears in
the free online manuals for your car at www.autozone.com ,
under "Emissions Controls."

The Throttle angle Sensor and Intake Air Temp sensor may
cause other problems not consistent with your symptoms (so
far).

It could be the TW sensor. I think that's come up here
before and is in the newsgroup archives.

I'd still do the air purge. I'd still keep the EACV in mind.
These too have come up as the source of idle problems. Just
not sure if they cause 'engine cold' idle problems.

Is it OEM?

 

Is TW sensor located under distributor?

Yes, it OEM.

 

Yes. It's called the "thermosensor" in the second link
above.

Are the links above not working for you for some reason?
They are pretty clear about this sensor's location.

That's way too early for an oxygen sensor to fail, normally,
then.

 

I checked the ECU trouble code. I got code 16 which is a fuel injector
system.

I think the fuel injector system is contaminated. According to this ->


http://media.honda.co.uk/car/owner/media/manuals/CRXManual/62SH220/6-59.pdf

rough idle and frequent stalling during warming are the sympton of
faulty injection.

I have to clean the fuel injection system. That is the only thing I can
do.

I can't afford to replace the whole injector system.

 

red cloud, you're a clinical retard. 10 minutes googling this group
would tell you all you need to know because your questions have been
answered here hundreds of times already. but instead, you waste hours
trolling with increasingly asinine comments, the above being a great
example.

you need to sell this car and take the bus since you're too dumb to
drive. and no, you can't post bus questions on this group.

 

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I don't recall you saying anything about __frequent stalling__ during
warm-up. That's the symptom of tight intake valves, at least on a Gen 1
CR-V. Next symptom is a Check Engine light and a $1,500 repair bill.
Have the valves been adjusted according to the maintenance schedule?

'Curly'

 

I do not have stalling problem when I push the gas. During warming
up,
sometimes I say the engine is trying to cut off because the RPM drop
almost to
the bottom and rise back quickly. Is not that stalling? But the
engine never
has been cut off. I do not know about valve adjustment in the past.
Thanks for telling
me that. I've to consider that too. Well I've to find the way to check
TW sensor
and EACV sensor after I done something about ECU trouble code.