MJO

Hi guys,

I am from the UK so hope I am allowed to post on the forum.

I have a D16V1 engine with 53k full honda history and serviced myself when I can.

Car is 2002 Civic sport



I have the following problem with my idle.

When I come to a stop the revs will go to 1k bounce to 1.2k then drop to around 100 revs (shake the car) then sit at 300-500. sometimes the car will stall but the majority of times it will go to about 100 revs.

Heres the spanner in the works.. when driving home at night (so colder temps) it will hit 1k revs then bounce to 1.2k then idle drops to around 500 which is about normal, I've had it stall / go low a few times but its certainly less prominent in these conditions so it could be temperature based?

No CEL codes

I have removed the throttle body and cleaned it along with the IACV. pulled the FI fuse out for 20secs done the 10min idle procedure and the car drove spot on! then after 100 miles its started doing it again!

I can get a replacement throttle body cheap and I am whether whether to get this done.

Would Valve clearances too tight cause this as had these done not long ago.

Any suggestions welcome!

MJO

Any chance the clutch could be causing this?

ezone

If the throttle cleaning and idle relearn got it working correctly for a short while, have you tried the same again yet?

What type of IAC does it use? If a rotary motor type, it may still be hanging up a little. Tap on it while it's acting up?


I've seen where incorrect valve clearances have caused unusual running problems similar to this on a different car, but I can't say if yours would do the same or not. If the clearances are not correct, then rectify that...just because.
I (personally) prefer to adjust valve clearances to the looser end of the spec range.

MJO

Hi Ezone,

Thanks for the response, I've heard of the tapping method with the back of a screwdriver.

I believe it is the rotary type, trouble is it might be hard to get to as the airbox covers an awful lot of the car. will have a look later on.

nsrhonda89

Are you using the stock air filter or aftermarket? Did you change your PCV valve? I find when I was using K&N drop in filter I used to have this issue. Does your car have a EGR valve? If you do, try cleaning it.

MJO

I am using the stock airbox

I am going to clean IACV on the weekend as last time I did not clean the wheel part of it! will update if this solves the problem for future users

PCV / EGR will be next if problems still occur

MJO

Ok, pulled apart the throttle body, took about the IACV and the wheel is not clogged. i have a question though, it will spin but if you turn it slowly there is a slight grinding sound, is this normal? or is it the bearing gone?

Also, I have some oil in the oem airbox, is this a sign the PCV is gone and therefore why this idle problem is happening?

All comments welcome

MJO

Picture of airbox, had to turn flash on so you can see the oil

I have ordered a new PCV valve and hose from Honda for £44 (~65$) as the car is on 50k and read these need to be changed around that time anyway. I am hoping this is the problem

ezone

The valve and shaft should move freely without obstruction.
Is there any drag feeling when it makes the noise?

Got a picture of your IAC valve? Just wondering what you have.

There could be reasons for oil to get into the airbox. Sustained high RPM operation and aggressive driving come to mind after seeing the pic of the car and you wearing the helmet LOL

Other reasons might include high oil level, slosh, and blow-by. Sustained high RPM operation and aggressive driving can create slosh and blow-by.

MJO

Haha, yes it does get driven hard, done 4 track days this year including the Nurburgring , I've decided to replace the PCV valve anyway and will be here on Friday.

I took some pics / vids, if you need anything more please let me know!

Here is a video

https://*******/F7jP

pics here







Can you see the slight chipping on the wheel? hard to tell but there is a shine to the metal where it looks to have chipped before? no idea if its meant to be or just random but worth showing none the less

ezone

Well that certainly looks spiffy clean. All it really needs is to be completely free to rotate through it's range of motion. The force produced by the windings in the electric portion is small, it doesn't take much to stop the valve from moving.

Is there any drag felt as the bearing makes noise?


I don't think the markings on the edge of the wheel are anything to worry about.

MJO

It feels ok to me, I'm thinking of buying a new throttle body anyway just to see what the rotation on that one feels like :P

Thanks for the help, I will update on Friday

ezone

Remember to perform the idle learn procedure!

MJO

pull FI fuse for 10 secs then idle for 10mins with no fans / ac etc? should this done cold?

ezone

Yeah, that one.

I don't want to take the time to hunt for a fuse so I'd probably pull a battery cable....I don't have to hunt for that and I can get most radio unlock codes faster than I can find a particular fuse LOL.

Actually, I often use the Honda scanner to do a PCM Reset. It wipes learned memory.

ezone

Sorry, I must have missed the edit.

Engine is supposed to be at operating temperature, all electrical loads turned off.

If the radiator fan runs during the learning period, stop the timer for the duration of the fan cycle...then continue.
Supposed to accumulate a total of 10 minutes running with no electrical loads.

MJO

ok PCV valve in, gace IACV and TB another clean and bought a new gasket for IACV.

Thought I had a vac leak at first as idle was very high at idle, but seems to be ECU learning as hasnt done it since. have done about 10 miles but will update after a longer drive tomorrow

MJO

Ok, I have 99 Ron in the fuel tank at the mo, I'm going to 95 Ron Fuel in as thats the most commonly used fuel for me and reset the PCM again. will update in a few days