accordeurodude

Hi All, my first post here, I owned a 1st gen about 3 years and had 2nd gen about 1 month:
So my 2nd Gen, 2009, was idling around 850-900 when warm and trans in D (waiting at lights) but the idle speed would drop to around 600 or so intermittently and the car seem as if its about to stall which I decided to fix.

So I cleaned out the throttle body (spraying only on paper towel). It was quite dirty and after that the idle speed went up to 1000rpm and stayed steady (trans in P) which I believe is too high (should be around 850?) Then I followed the idle learn procedure but it still stays around 1000RPM.

I'm thinking I've not followed the procedure correctly. 3000RPM until radiator fan on or coolant above 90C (I used the coolant temp method using Torque app). then idle 5min + fan on time. I see the factory manual says to reset withHDS first. I dont have an HDS. Is the HDS absolutely necessary? Is there another way to do it (I also tried reset using the 30s hold down the accelerator pedal without success)? I didnt try pulling a fuse. When looking on youtube it seems people succesfully do a relearn without any kind of reset, just folllowing the 3000rpm/1000rpm method only.

I also decided to try the IACV and fast idle thermo valve, but compared to the 1st gen they dont seem to exist this must all be done through the ECU/throttle body now? If I did have a leaking thermo valve, I guess the idle learn would compensate for this?

Appreciate any help

accordeurodude

I also tried battery and fuses out with no difference. Looking at this link below it seems a scanner or (competent) honda dealer is needed to properly reset the idle speed and throttle body

Fluctuating Idle after cleaning Throttle Body - 8th Generation Honda Civic Forum

My car is also doing the lurching described to some extent while driving in stop-go traffic but not too bad. Think I'm gonna try the "drive a couple of months" solution and see if the car adjusts itself.

accordeurodude

OK so after 1 month nothing is changing with the idle and it still revs high, it isnt learning by itself. So I solved this by manually resetting the ecu using the battery cable reset method (which likely can solve many other problems also as well as reset fault codes):

To do the battery cable reset- follow this: 1. Remove negative battery terminal. 2. Remove positive battery terminal. 3 Be sure you arent going to make contact with the battery, for later steps possibly even remove it from the car if needed 4. Connect the battery cables together either using a jumper cable or clamp them together if they reach. 5. Turn on your key to on (not ACC, to on) and yes there will be no lights on the dash. 6. Leave for 10 minutes. 7 Turn your key back to off, reconnect positive then negative and THEN follow the idle relearn procedure you will find pasted all over youtube (or just start the car rev 3k rpm until the car reaches temp and then leave it to idle 10 min). You will also need the radio code and possibly relearn your auto windows, for which there is good info for on youtube.

For me after warming up at 3000rpm the idle quite quickly returned to 850rpm, but I left it 10min anyway. the correct procedure is idle 5 min minus the time the radiator fan is on, but who can bothered with all the math, I just go inside for 10 min and chill out although I also made a mark on the radiator fan beforehand so I know it came on.

This procedure is a honda legit procedure and is also described in the january 2012 edition of acura service news as in the link below

https://acurazine.com/forums/third-g...letins-588838/

There isnt much info about this battery cable reset around and not in association with the cleaning the throttle body so I've pasted it around.