Help! RPM up & down during idling

[edddial]

..and moving!

Friends,

My car is having some tricky problem lately. History:

While driving (highway), suddenly I feel the car is a little jerking when I step off the gas. The same thing happen when I step on the gas. In other word, it is not smooth as usual.
After sometime, the RPM start to rise a little even I didn't step further on the gas.
In the later stage, the RPM rise until 3000 by itself. Also when in free gear.

I stop the car, keep it 'OFF' for sometime & start again. During idling, the RPM goes up & down. It's continuous up & down forever. So it goes like as low as normal idling and up to 3000 rpm. If I continue driving, the car will jerking like I step on the gas 'on and off'.

So the RPM is up & down during idling & moving.

I sent to Honda SC, they clean the throttle body & change one part (with motor) that controlled the air next to the intake manifold. Well, it's ok for like 2 weeks and the problem come back. :sad_smile:

I'm wondering if there is something else causing this problem. My car is running on F20B Auto. I have e-manage installed for nearly 3 years, I don't see any error on that unit.

Any good workshop around Shah Alam that could diagnose this problem? Any idea what is wrong?

Thanks!

 

[achor]

maybe ur distributor?

 

[JacEK]

well, same thing happened to me 2 weeks ago. changed the same part like urs, but so far so good.

may be like wat achor said, could b da dist.

 

[pok nik]

perhaps ur distributor or maybe fuel problem..however, since u mentioned that u hv ur tb cleaned and its ok for 2 weeks or so..that means ur tb must be very dirty and the cause of that would be from the air filter..check ur airfilter and take a look at a hole at the air ram, maybe ur minyak itam overflow into the air ram and cause the tb to be dirty...it happened to me once when i was using an hks air filter and my tb always got dirty...try it first but i m not very sure since i m not a mekanic...just a piece of mind that i think might help...gud luck, bro

 

[sasuke]

ECU also must check.

 

[jerm]

always check your ecu for any error codes first when something like that happens to your car

you can always refer the codes online

 

[avantasia]

plug error?

or cable plug?

 

[kuNyit]

could be your battery ground (-ve) cable. this also need to watch out!!!

 

[pok nik]

wahhh!!! so much to cek,,,die la owner like this!!haha...very very very best of luck lah brader eddial..

 

[edddial]

Problem solved! The RACV dirty, after clean-up the engine is back to normal as usual. It could be the HKS air filter too. I'll change that too. Thank you very much guys!

 

[JacEK]

mind if i ask...wat does RACV stands for?

 

[edddial]

If not mistaken Rotary Air Control Valve or something like that (located at the Intake Manifold). I got it from a translated website (japanese) forwarded by Aja. There is a motor attached to it that control the valve.

Which air filter is good/better? K&N or HKS? Where to source this air filter for my F20B? I know N1 at Sunway selling HKS for F20B but they don't have K&N.

 

[^Dreamerz^]

i heard sometimes using DYNO machine can help to figure out problems..
maybe u can try ask around about this..
not really a 100% sure..

 

[pok nik]

i used to use hks and i needed to service my tb all the time,so i guess it is not good for ur car's health...k&n is good manufacturer of air filters but i seldom see vtec owners using it, so i do not recommend u to use oso...try apexi...or maybe simota..gives out better response based on my experience..

 

[edddial]

I think HKS is not too bad. What when wrong was the installer did not reuse the rubber attached to the ori air filter. HKS airfilter doesn't come with this rubber. Causing gap that allow air to flow freely towards TB. Lucky I didn't throw my original one, so I just attached it to my HKS.

 

[Chatt]

From my experience it is due to dist,coz same symptom occur to my friend & me.After did a lot of trouble shooting.

 

[rivers]

GUys, i am having almost the similar proble. BUt it only happens only when the engine is cold. No problem when its been runnng for 10 minutes or so. no problem with cold start but after starting, the rpm goes to 1k and when you step on the accelarator, straight away it will go down to 100-200rpm. when i engage to first gear and move the car per normal and when i step on the clutch, the rpm would sometimes drop to even 0 !!

most of the time when my mechani washes the TB everything seems fine for a few weeks...he suggested to change the TB for about RM 400+ but i have a feeling its not the TB...

i am driving a SR4 SOHC non V-Tec..any suggestions?

 

[pok nik]

bro rivers...wat air filter ur using?like i said earlier, the air filter may have caused the tb to get dirty coz it tends to suck everything from the outside...if it is the dist, the car would not start at all... like i experienced a year ago..

 

[ahchi]

Hi edddial, may I know are you driving CF4 or you transplant the F20B into other Honda chasis (just curious to ask)?
BTW, I believe this kind of problem is kinda common for Honda car and I guess most probably the root cause is like what edddial say, the RACV on his F20B malfunction. I encountered the similar problem on my SM4 half year ago, but it's the EACV (electronicl air control valve problem, should be similar function as RACV) faulty.
One thing I observe is, I don't know are those mechanic really don't know the root cause or they just simply with intention, ask you to change the TB first. By right changing a EACV (buy from chop shop) is just merely <RM100 only, instead of paying few hundreds for TB.

 

[edddial]

ahchi, it's CF4. During the ECU check, it's also pointing to air control valve. Accodring to the Honda SC, if the dist problem the car wouldn't start & I'll get warning light. So far my car is ok.