imported_loudsubz

I recently got a swap from Scott, he put a D16Y8 engine in my 94 sedan, and we used the P28 ecu to run it for obd1.

This isn't really a problem but its interesting none the less.

When the engine is cold, and I first start it in the morning, the car idles at around 2000 rpm for a few minutes then when it starts to get warmed up the idle bounces from 1500 to 2000 rpm soemtimes from 3 to 6 times going up and down, (sounds like im pressing an releasing the gas). Then after 2 to 6 times it stays at 1500 then slowly goes to 1000 over the period of about 20 seconds, then the temp gauge starts to rise to the bottom "C" mark on the cluster.

After that its fine, if I start it up awhile later if the engine is still warm it will idle around 1000 or just above, this occourance only happens first thing in the morning or if the cars been left for a few hours and the engine temp drops.

But funny thing is, its not constant, most mornings it does it, and ive noticed a few where the rpm's just drop normall from 2000 to 1000 without the bounce at all, just nice and smooth.

Any clue what this might be? sticky valve? sensor on the fritz?

imported_gatherer

think it might be a sensor... but compromises did you have to make to get an obd2 engine to run on an obd1 ecu?

EL_CIVIC

its one of the 3 problems...

iac valve..
primary o2
secondary 02

get it checked.......
lates.

imported_loudsubz

does my car have more than 1 o2 sensor? I know of 1 o2 sensor is on my header, on the front, not in the collector like the 02 sensor should be on the obd2 engines.

Jacob

loudsubz, i had the same thing happen to my bros car, except his was an h22a and his was consistent. It would idle normal when cold and when warms ur it happens, As soon as he comes online i'll ask him What he did exactly to get rid of it.


- Jacob

Jacob

"first to eliminate the possibility of it being the egr...cut out a piece of tine and clog it...first just disconnect the sensor, and then finally tell him if all else fails check for a vacuum leak and then if he does not find a vaccuum leak tell him to play with his idle control screw"

Thats what my brother said. I'm guessing he did this and now it doesn't do it anymore.

neilff

i have same problem bro
92 civic si

tell me if you figure that shizzle out

exact same prob.

PULOVR

It could also be a worn/old throtle cable getting stuck. Check to see if the flap in the throtle body is closed all the way before the car is started. I'll bet it's not.

Also check to see if the flap moves freely.....(deosn't get stuck/tough).

When was the last time you cleaned your throtle body, and throtle body assembly?

Perfectionist51

Check your fast idle valve.. Make sure that the plastic valve seat has not unscrewed itself.. I put up with a horrible idle (bouncing between 1500 and 3000 rpm) for months before I figured it out.. The plastic seat had wound itself completely out to the point that it was rattling around inside the aluminum casing.

I touched it with some threadlock and wound it back in.

imported_loudsubz

thanks guys.

Found some good links as well.

http://www.honda-tech.com/zerothread?id=343980

http://www.hondaracing.ca/maintenanc...peed/index.htm

bbarbulo

iTrader: (2)

you should really check whether this happens in closed loop or open loop...check with a scanner... or there is another way to check by bridging some pins...it's in the repair manual somewhere. knowing where exactly it happens open or closed loop will help us eliminate sensors and provide areas to focus on.