Quote:
Originally Posted by archie bunker  take it to the dealer. codes have to be cleared and it has to relearn idle by running engine for 45 mins. they replaced my IACV for free and its a 97 civic LX. they told me its covered by warranty. probably due to emissions |
Thank you kind sir ! The ECM really needs to relearn how to idle
wallice here is what happened for me and my 1996 CX hatchback, with D16Y7 engine. Those of you that would want to get straight to the point can scroll down to the 'What I did about it' section of the post.
It all started last January. The MIL light came on right after the holidays. The engine did idle a bit rough from time to time and the car was due for an oil change and a timing belt so hey, off to the dealer it went. The dealer replaced the chain and did the usual stuff, plus replaced the O2 sensor. All was well.
One month later the occasional rough idle was back. Since it was 20 belw outside I decided to ride it out until spring got here. It got worse. Two weeks later I had a severe rough idle and the car would even die on me from time to time on stop signs and red lights. No MIL, so I suspected condensation in the gas tank and did what everybody does in those cases. No good. The MIL finaly came on and back to the dealer it went. Replacing the MAP sensor cured that... Fair enough but with so much sensor business I was starting to think NASA should probably orbit Civics around Mars instead of billion dollar probes.
The new MAP carried me over to this summer without a hiccup, at which point the motorcycle became my primary means of transportation.
One morning thunderstoms were really raging and it was raining sideways, so no bike. Started up the car, drove to work and in the parking lot I noticed the revs were yoyoing between 1k and 2k. Further putzing around revealed it only occured on a warm engine.
I decided the culprit had to be the IACV since most everything else on the throttle body had been replaced. I pulled the the connector on the IACV while the engine was yoyoing and it immediately stabilized at 1.5k. MIL came on of course but that got cleared later.
What I did about it :
Step 1
I removed the Air cleaner, got the engine warm and yoyoing, put my palm on the throttle body's intake port and the engine died.
Result : No leaks (good)
Step 2
Went to a scrap yard and pulled an IACV from a dead 96 hatchback (5$). Took off the throttle cable, all connectors, both coolant hoses from the IACV and removed the throttle body from my car.
Result : Minor sunburn
Step 3
Went to the dealer and bought IACV o-ring and TB gasket ( 5$ each ). Removed original IACV from TB, cleaned TB, installed *new* cleaned IACV with new o-ring, put throttle body back in car with new gasket, connected everything and started it up.
Result : Steady idle à 1.5k with no MIL
Step 5
Play with idle adjust screw on TB.
Result : Can get it to yoyo again by raising idle up over 2k, cannot get it lower than 1.5 with idle adjust screw. Put screw back the way it was before I started playing with it.
Step 4
Despair, search web, read archie bunker's post about relearning to idle, start car and go for 15 min drive, park car, let it idle and WATCH THE IDLE GO DOWN TO 850, celebrate by blasting stereo.
Result : register on forum and write longest post evar.
I hope this can be useful to someone.
wallice : after having replaced the IACV you could try bringing the idle down with the adjust screw to see if it stabilizes at 1.5k like it did for me. If it does, reset the ECM and go for a short drive maybe ?
(edited for silly numbers and typo madness)
