alright so the ZC's idle slowly fluctuates.
my old accord did the same thing, ended up being the TPS. but the accord did it faster, like waaa waaa waaa waaa.
the ZC is more like wa..a...wa...a. it goes from about 1200 to just under 1000rpm.
what sensor is messin up?? no codes as of yet...

 

Sounds like it could be a vacuum leak.

 

I had the same problem with my old HF engine. I swaped a new ZC in and the problem went away! Expensive fix! Seriously, I would like to know what the problem was also.

 

we all would! there have been a ton of posts on this, and going through the archives gives
about 20 different sources that could be the problem, like TPS, EACV, vacuum lines etc. etc.
If anybody does figure it out, they should be bronzed. It does seem that engines from Japan
are gummier than we are used to (weird fuel additives in Japan?), and the intake manifolds and
all associated components seem to suffer as a result.

 

There is a flat head screw on your throttle body. It faces the passanger side of the car. Try adjusting this screw then reset your ECU. I had the same problema few weeks ago week. This fixed it.

 

Just remember to unplug the IACV first when you adjust the base idle. And do it on a warm engine.

 

might check the tw sensor and also coolant level

 

just curious...what would the coolant have to do with it?
please explain.

 

we have done a lot of zc swaps and the fluctuating idle can usually be traced to either a vacuum leak or a bad tw sensor - the best we can determine is since the tw sensor is at the very top of the engine, if the coolant level is low it doesn't reach the sensor causing confusion to the ecu (which doesn't throw a CEE code for this) - filling the coolant level usually corrects the problem if everything else is o.k.

whoops! typo - should say CEL code.


[Modified by jlicrx, 3:18 PM 10/3/2002]

 

sorry guys, what's a TW sensor?

 

water temperature

 

i would say EACV. my car was doing the exact same thing, i took it off cleaned it out put it back on ran fine, couple weeks later i started throwing a code and it started again. it was throwing a code for the EACV (code 14 i believe). I took mine off and replaced it with one off a 92 cx haven't had any problems since.

 

ZCs are such funny little motors.
so today it's been idling PERFECT. rock steady at 750.
i didn't do a damn thing to it. wtf?