[pranavt]

Originally Posted by Games Goblin

* When I race the engine, the RPM goes up and upon releasing the accelerator, the RPM comes down only slowly and goes up again, without me pressing the accelerator (!)

Your IACV might be getting faulty. So you don't get a CEL but can't idle properly. A busted IACV would throw a CEL, so would a busted O2 sensor. However, a blocked/faulty IACV would most probably not show any error. Are you sure your dealer has not taken you for a ride by making you change the O2 sensor while the real problem is the IACV? Are you sure he has cleaned the IACV properly? Can you find a known working IACV from someone else with an OHC?

If you have your old O2 sensor, you can connect it and check the error code yourself. The guide I posted on the previous page is very very simple to follow and doesn't take more than 10 minutes. If it doesn't throw an O2 code, then your dealer might have cheated you altogether.

[ssjr0498]

Ok mate,

just went through the thread and I was having somewhat same issues after I changed my throttlebody from a imported(thai spec) one to the stock one, the reason being that this throttlebody did not have a place to connect the IACV and hence I had the CEL glowing permanently and whenever I would switch the a/c on, I would have to hold throttle to stop the engine from dying.

After successfully removing the imported TB and placing the stock TB, the woes started. Initially I had misjudged and put the MAP sensor wire onto the TPS and the TPS wire to the MAP sensor hence the car would not respond to the change in the butterfly positon. After figuring this out and getting the TPS to function properly the problem of IDLING started. NO CEL but the car would simply not IDLE, in my case it was fluctuating between 1000-2000rpm.

Please do the following steps to isolate the problem, I have a very strong feeling that the Honda engineers have not cleaned ur IACV properly.

1. Take out your filter, thereby exposing your throttlebody.
2. On the left side of your throttlebody(with you facing the engine bay from the driver side) you will see a small hole, which is the IAC valve, take your finger and block it by say 25%
3. Notice how your car behaves, technically the rpm should immediately drop.
4. If it does, on the top left outside the throttlebody you will notice the IAControl screw, turn that and while turning it see if you can see some plate kind of thing closing the small hole(IACV). If it is moving, try to adjust the idling. I guess in your case its not cuz, I am sure the Honda guys would have tried doing this!
5. If NOT, take the throttle body out from the intake manifold and open it.
6. Notice that there is a small chamber kind of thing which sits right next to that hole outside the plenum and is closed with the help of 2 nuts.
7. Open these nuts and you will see a rubber gasket, remove the gasket and then you will see a long cylindrical kind of a thing which has 2 open paths cut on it, this is the plate which rotates behind the IACV thereby controlling the Idle.
8. Make sure that this thing is rotating freely and effortlessly, wash it with diesel if needed, use a brush if you want too!
9. Dry the TB and place the rubber gasket and assemble the TB properly.
10. Take a screw driver and see if the plate is rotating when you move the IAC Screw.
11. If yes, then plonk the tb back onto the manifold, connect the sensor wires and crank the car.( LEAVE THE IACV sensor, do not connect that at this point in time)
12. Let the car warm up with the fans spinning up atleast once
13. Adjust the idle, and then switch off the engine
14. Connect the IACV Sensor and place the filter
15. Crank your car, there should be no CEL and you should be all set.

If the above steps do not solve your problem, replace the TB with another TB and check. This cannot be a ECU issue.

Hope this helps!

Regards
Shrey

Originally Posted by Games Goblin

Hi pranavt IAT Sensor is correctly placed. As per your request, posting step by step description of the problem from the beginning once more, I also think that this has become confusing after 2 pages of discussion :

• I installed a free flow exhaust from automech on my Honda City Type II Automatic. I ordered the exhaust from Mumbai and got it installed from my Honda Dealer in Cochin.
• My car was stock condition before the installation of the exhaust, except for a K&N replacement filter I installed about a year ago.
• But after the installation, my idling RPM went up to 1500 RPM (from 700 RPM, which was the normal idle of my car) The Honda guys checked everything (sensors etc) but could did not find any problem.
• They waited for a day and idle RPM went down to 1000 RPM. I took delivery of the car and the service engineer advised me to drive the car for 2-3 days and see if the problem disappears and asked me to return if the problem is not fixed by then..
• The Check Engine warning light stayed on in my dashboard.
• My Honda Dealer confirmed that my O2 sensor needed replacement, as it was found to be faulty after a hi-scan.
• I replaced the O2 Sensor and the CEL Light has turned off. But the idle RPM stays the same (1000 RPM)!! ECU was reset by Honda mechanics after replacing the O2 sensor
• Here is what was done at 50,000 KM service at honda
  
  * Installed Automech Freeflow system (Headers & Exhaust)
  * TB was cleaned and checked during the 50,000 KM service at Honda (after the FFE was fitted)
  * Injectors and Plugs were cleaned by them
  * Cleaned IACV as part of the 50,000 KM service
  
  TBH Honda guys are baffled by this problem -- they have tried everything they could possibly think of.
• This is the present situation with my car:
  
  * As discussed before, Idle is at 1000 RPM
  * When I race the engine, the RPM goes up and upon releasing the accelerator, the RPM comes down only slowly and goes up again, without me pressing the accelerator (!)
• and BTW apart from this idling problem, the car is running perfectly - FFE has caused a marked improvement in sound and performance (esp. pulling in the lower RPMs) If this idling niggle is solved, the car will be 100% perfect.

I can take a video if you want, just inform me.

oh and forgot to mention that fellow BHPian shailu called me regarding the RPM drop (read the beginning of this thread) and he confirmed that it was normal (it was also pointed out by Ravveendrra and others). Thanks mates!

Oh, and Mods, can you please change the title of the thread to something like : "Honda City Type II A/T Idling at 1000 RPM"

[Games Goblin]

Hi Friends, Sorry for not posting back here for so long as I was a bit busy. After long discussions here at T-BHP, My Honda Dealer and many others, my problem is solved. How? I switched back to my stock muffler and headers!

A little back-story on why I got the Automech FFE for the OHC:

The OHC had done 50,000 kms and its stock muffler pipe had rusted away. This was pointed out by the service engineer at HASS and I asked for a quote on the muffler pipe. Rs.10,000 was the propmt reply for the muffler end section

After hearing this, I checked around for a second opinion and discovered that non-OEM muffler end pipes were available for as low as Rs.3.5k (!)

The next thing I did was contact automech and get a quote for their FFE System. I got a really good quote [13.xx k] (remember HASS quoted 10k for the end section alone ) and after reading all about the automech exhausts in T-BHP, I decided to go in for the FFE system rather than replacing the end section.

The order was placed at the automech dealer in my city and the shop owner gave an ETA of one week. In today's world of half-hearted promises, I was pleasantly surprised when the shop owner called me EXACTLY a week later and told me the FFE system had arrived Real professionalism there! Kudos to automech!

The FFE system itself was good. The build quality was better than I expected and it came with heat proof coating. I got it installed at my Honda Dealer. The system was a perfect bolt on as promised by automech and the install was really neat.

The rest of the story you know... [for those who don't, read the thread from the beginning....]

Now, since the car was primarily being used by my dad, he was really upset at the idling problem and drop in fuel economy [changed his driving style due to the FFE system! Now that is no surprise now, is it ]

We had stored the stock exhaust system away and my father got it repaired at a local workshop and he informed me that he was going to switch back to stock exhaust system. I was against this [losing that awesome soundtrack and performance???], but since that car was primarily used by him, he won the argument.

We visited HASS last sunday (29th nov) and got the stock system fitted back. And after starting up the car for the first time after the stock exhaust system was back in place, the car idled at 750 RPMs , much to the delight of my dad and the HASS personnel.

We discussed the issue with HASS engineer and he informed me that the problem was with the ECU [which was also pointed out my Automech in their e-mail] He told me that the ECU was configured for stock setup and if aftermarket FFE is installed, such problems might arise.

He further added that chipping/modding the ECU to accommodate the new FFE system will help. So can anyone throw some light on this point?? Also, could this problem be due to the fact that my OHC is an automatic? I haven't come across a BHPian who has installed an FFE on an OHC A/T.

The car is back to its old self now but I sorely miss the soundtrack and that sense of urgency when you push the throttle! And overtaking was so much more fun with the FFE! Dad is happy that the idling problem is solved and the fuel economy is back to normal again!

oh, and special thanks to ssjr0498 for that long and informative post! But I lack the expertise to perform such work!

So there you have it. Please post your opinion guys! Mods, can you please add prefix [Solved] to the thread topic?

[pranavt]

Originally Posted by Games Goblin

We discussed the issue with HASS engineer and he informed me that the problem was with the ECU [which was also pointed out my Automech in their e-mail] He told me that the ECU was configured for stock setup and if aftermarket FFE is installed, such problems might arise.

He further added that chipping/modding the ECU to accommodate the new FFE system will help. So can anyone throw some light on this point??

He is talking out of his fat backside. You do not need a remap to accomodate something as simple as a less restrictive exhaust. The problem lies elsewhere.

[Games Goblin]

Hi guys

I came across another member dhananjay who has installed Automech FFE on his City A/T. I have e-mailed him about his experience with the install, so i'll report back here.

pranavt,

Automech too told that it has nothing to do with the exhaust, but with the ECU. I am quoting their e-mail

Dear Mr xxxx
This should not be happening, as it is not related to the exhaust, it is all concerned with the ECU, the unit which controls engine function.

I read through your ITB project [awesome work there btw] and have understood that you know your way quite well around the OHC's ECU. So from your experience with the ECU, can this be fixed by remapping the ECU? Forgive me, but I am no expert in this field

Still I have nagging doubts if the problem is related to the fact that my car is an automatic

BTW the FFE is now on sale in the classifieds, as I am a bit short on cash and I cannot use it unless this problem is solved

[pranavt]

Thanks

You do not need a remap in the first place. The higher idling was due to the ECU or the IACV, yes. But it should have nothing to do with your FFE directly. What you can do is find out about the error codes yourself from the link I posted. It's a 2 minute job and doesn't involve anything dangerous. Just jump the service connector, and turn the key till ignition. Don't start the car. Get the error codes, turn off ignition, remove key and disconnect the service connector jumper.

If you can, do it with the FFE installed and all sensors connected. That will pinpoint the errors that the ECU is finding, if any. Forget the fact that Honda people told you of XYZ problem and do it yourself. They will obviously try to sell you a new O2 sensor for 16k. The problem could be something else altogether.