Honda City iDSI idle rpm problem

[ahsanonline]

First try this on a running engine and see how it behaves:

while engine running, remove the connector on the IACV. Rpm should go up automatically. Then re-connect the connector and see if it repeats the same behaviour as it does on start-up.

If you want to clean it, first try the carb cleaner method, you wont need to remove it for that...

[hash4u]

my 2006 city with 70,000kms on clock started to stall on iddle /petrol
went for
throtle body svc,
plug cleaning,
iddle valve cleaning,
tappet check,

in 700-800 rupees the car is smooth like a baby(its actually better then previous state of iddling issues even)

[devilz_apprentice]

What exactly is involved in Throttle Body service?

[devilz_apprentice]

Bump! Awaiting Xulifqar's advice.

[qwertypoiu]

Go to Honda 3s dealer and get your throttle body and iddle valve cleaning(they will do setting if needed). every thing will be great after that.

To access the rockers, intake manifolds and throttle body were completely dismantled and removed. However, no adjustment or work was done on the throttle body. It's after this that I have started experiencing this.

look at the small things 47k is NO mileage at all IF it was 200k or more then you might have needed xulfiqar's advice since multiple factors would have been involved.

[ahsanonline]

In throttle body service they just take it off, take off the IACV and clean it, clean the bore of the throttle body with rags/some petrol and brush, then put it back together. Thats it.

If you mess with the TPS or the throttle stop screw on the throttle body.....then consider your TB screwed.

There are no adjustments to be made in the clean up process. Only dismantle/put it back together.

Honda 3s (like all manufacturers' official dealerships) will probably milk your wallet.

[devilz_apprentice]

Exactly! I still remember that back in 2007 when the car went to them for regular check up, they said that TB needs to be replaced! I told them to just f**k themselves, bow down with their head between their legs and give it their best shot!
What i have failed to understand is that how come the idle has gone wrong all of sudden after that service. Though nothing was touched or adjusted. The TB was just taken off, and installed back after rocker adjustment. The IACV, MAF, TPS or any other part remained attached to the intake manifolds and TB. Only electric grips and pipes were taken off.
There is one other thing, from what i understand some coolant also passes through the IACV. Could it be possible that an air pocket might have entered the system resulting in a malfunctioning IACV? These coolant pipes were taken off while dismantling TB.
Here is reference picture of the IACV used in L12A2's TB.


The black part is the solenoid which is fixed to the mechanical valve using flat head screws. Due to this the solenoid cannot be separated from the valve assembly.

[devilz_apprentice]

bump!!!

[ahsanonline]

You cant separate the IAC thing from idle valve assembly. Correct. Nobody wants to do that. When you take the IAC+V off from the TB itself, the rotating valve is exposed. That is the thing that has to be cleaned and made sure that its rotating properly.

Well it could be two things, one: rocker adjustment didn't go right, or two, minute dust might've gotten stuck in IACV or its sticking somewhere in it's range of motion.
And the air bubble thing could be right, but I doubt it. Anyway, you should make sure that the radiator is topped up to the brim; and you can verify that while engine is running and radiator cap is off.

[devilz_apprentice]

Shouldn't improper rocker adjustment also contribute to fluctuating rpm as well? But i don't have any fluctuating rpm, the problem is different.
I'll dismantle the TB in a few days to get the IACV out. How can i check the rotating mechanism? It's only accessible by removing the solenoid, though the rotating valve is exposed, but the solenoid needs to be removed to rotate it.

[ahsanonline]

The solenoid doesn't need removing from the valve itself - they are calibrated and fixed together.

The valve can be seen and you can use your finger to do the rotating. Its simple.

Its a 30 minute operation at most, start to finish. Simple stuff.

Did you try removing the IACV connector while engine is running? Did the rpm go up (and to what speed)?

[funny123]

Hello,
Salutation to this one of the forum site.
Myself Jyaky Petter from the nation of India
at this point we are going away to thrash out in the automobile discussion
We can argue many kind of debate from the forum
We not only discuss but also dig up a lot more knowledge from
Various Google experts.
Thank you………………………………………………………..
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2013 MERCEDES BENZ SL-CLASS

[fawadakbarkhan]

my issue isn't resolved yet... cng tuning isn't related to it...

any other ideas???

[devilz_apprentice]

Update: Today i decided to open up the throttle body and inspect the condition of the IACV as a DIY. Though I have never seen how a dirty TB looks like, but this TB appeared to be in a pretty bad condition. I didn't take the picture of the TB, however I am attaching the pic of the the dirt and debris that got off of it by just a single spray of the Carby Cleaner.

And the inside of the manifold is a horror story as well. Below are the two pictures of what was inside. I didn't knew what to do with this and how to clean the inside of the manifold, so i just sprayed a generous amount of the carby cleaner while the engine was off, I knew i screwed up here. But still i'd like to correct it, yet i don't know wht to do.

Here the pics of the IACV before clean-up. IACV was thoroughly cleaned with the carby cleaner using cotton buds, brush and cotton cloth. And to prevent lint from settling in, i used blower to dry it up. Same was done with the TB.

Results: Nothing has improved, things have become worse :P. Before this, idle rpm(warm engine) was 700 and now it's 850. The cold idle used to be 1200 and now it has risen to 1500!
Even though the problem was the initial fluctuation in the idle rpm, but the idle was pretty smooth. However, after my ''panga'' today, the idle has become quite rough at 850. I haven't driven the car yet, I am just noticing the idle rpm. Maybe if i drive the car, things might get better?
Before this, the initial fluctuation was from 700 to 200 and now this fluctuation has moved to the bracket of 850 to 500.
Again, none of the sensors were tempered with, only grips were taken off and no adjustments were done. Only IACV was cleaned.

Awaiting response, from the experts!

Regards.

[coolsmart]

Such thing happened to me only on CNG, when cng air idel screws need adjustment.
check ur car without putting the air-filter on and give it some full throtlle for second or two.

[tayyabbaig]

Any black smoke from the exhaust? How much black smoke came from the exhaust after the first start up. And for how long the black smoke kept coming?
The same thing happened to me in my civic after cleaning of TB, the problem appeared when i sprayed a massive amount of carb cleaner in the intake manifold just to clean it. Black smoke kept coming until I fix it from dealership. They fix some readings from their computer and i was happily out of the workshop within 10 mins.

[devilz_apprentice]

When i initially sprayed the carby cleaner in the TB with the engine running, i didn't notice any black smoke coming from the exhaust though i checked for it. And after this i sprayed generous amount of carby cleaner in the intake manifold with the TB taken off and engine off(obviously). The later shouldn't have been done as it would do no good.
i am very much concerned about the debris that is in the intake manifold. It's oily and full of soot.

[ahsanonline]

Spraying carb cleaner into the engine in that amount....bad choice. But its done so....

Seeing normal city startups, rpm goes up to 2000 and then settles down at normal. So yours just got a bit better from this cleaning operation. The band has moved up but still needs improving.

I haven't tried this but its an idea short of going to a honda 3s dealership: Give the car a couple full throttle runs to clear its throat. Full throttle meaning 2nd gear pull right till just before rpm redlines. Then car parked overnight but remove the battery -ve connection when going to bed (if you have an audio system you might want to save your settings). An overnight disconnect might reset the ecu nice and proper - otherwise its off to the dealership to get your car brainwashed.

As for the gunk, yes it contributes to bad performance (including idle problems).

[ahsanonline]

my issue isn't resolved yet... cng tuning isn't related to it...

any other ideas???

did you get your spark plugs replaced? its a must...especially after 45,000 kms

[devilz_apprentice]

what to do to clean up the gunk from inside the manifold? And why is it there in the first place?