BlueEM2

iTrader: (1)

This topic has been absolutely murdered on this forum. I just logged on and saw two more posts about "Poor Idle". So, I'm going to try and remember all the reasons right now even though I just worked a 12 hour shift.

I've kind of been adding to this as I learn more so it's getting long and a bit choppy so bear with me. One day I'll correct it and make it nice. It is long but if you really WANT to fix your idle you WILL read it.

I'll start by saying, if the car is throwing a check engine light at you. It's crying for your attention. So go give it the attention it deserves, and get the codes checked. It might actually tell you what's wrong with it!

The following link is a good place to start. It has lots of pictures and instructions of how to do a lot of stuff that might correct your idle issues.
https://www.civicforums.com/forums/7...e-up-mods.html

The most common idle issues are caused by: and resolved by:

1. Dirty throttle body and the sensors and valves that surround it. The best way to clean your throttle body is to actually remove it from the car and spray it with throttle body cleaner and a toothbrush. Remove all the sensors and spray them with the stuff until they are clean. Be careful with the TPS sensor as it's very hard to calibrate, I suggest not cleaning or messing with it. If one of the sensors is actually defective it will cause crap idle, most of them will throw a check engine light.

If you are having issues with the TPS sensor and you know for 100% that it is the TPS sensor. Buy a used throttle body on ebay. It's the best way to replace the sensor because you can usually get an entire throttle body with all the sensors on it for 80 bucks. Just make sure the one you buy has the sensors.

2. A vacuum leak. This generally happens when a hose starts to leak around the intake manifold because it gets old and loses it's integrity. It is also caused by shot gaskets such as the intake manifold gasket itself The best way to check for a vacuum leak is to have the car idling and spray the throttle body with throttle body cleaner at various spots (1 spot at a time so you can pinpoint the issue). You will notice an RPM change if there is a vacuum leak after you have sprayed the said spot. Another option is soapy water. Spray it around and look for bubbles.

3. Spark issue. If the spark plugs, wires, cap and rotor are old... Change them before anything else because they are effin' cheap, and part of the regular maintenance of the vehicle. So change them, cheap ***. On a 7th gen the culprit might actually be a coil pack.

^ Use only NGK or Denso spark plugs, any others WILL cause issues, if not now, later.

4. Clogged fuel injectors will cause crap idle. I would probably resort to this last after the things above because you can't really clean them yourself... I wouldn't anyway. You will often get a cylinder misfire code if you have clogged injectors.

5. Change your air filter... Every car needs to breathe.

6. It's possibly your catalytic converter is shot or on its way out!

Now for the expensive stuff:

1. Timing is off. This is a bit more expensive to fix and can destroy the engine if it's not fixed. It's important that you get this fixed A.S.A.P. You have to take it to a shop to diagnose properly, tell them to check the timing.

2. Compression loss. Something is messed up, either head gasket or piston rings are causing you to lose compression and making the car idle like sheeyat.

3. Head gasket failure. When a head gasket fails the cylinders get injected with water or coolant and make the car idle like sheeyat. You can tell this by looking for white in the exhaust, and sometimes the coolant overflow reservoir overflows. Almost a dead giveaway of a failed head gasket.

4. A bent valve this would definitely cause crap idle. Along with a popping or ticking noise that goes with it.

5. Distributor is toast. Not delivering spark when and where it should causes crap idle.

I know this is on the 7th gen mechanical problems but I included the Dizzy anyway for those that have previous gens looking here. In other words, if you have a 7th gen civic you DONT have a distributor, or spark plug wires, so they aren't your problem.

Any time you play around with the throttle body and that kind of stuff. Whether it's cleaning it or changing parts, make sure you do an idle re-learn... Here is how to do it as quoted from gearbox:


I'm too tired to think, I'm going to sleep. I'm sure someone will have more to say about this at a more reasonable hour!!

rossx34

Hi, this is my first post on this forum but I have read a lot here on what do to.

So here is my problem. I own a 2001 Honda Civic DX. About 140k miles. About 6 months ago it started idling a little rough, nothing big at first, didn't think much of it. It has steadily gotten worse, to the point where about 2 months ago I was afraid to drive it anymore due to very, very rough idle. SO I began to work on it. I replaced all 4 engine mounts first, this didn't help in the slightest. I then put a new Valve Cover Gasket on, no help either. I then replaced the Spark Plugs, no help there. I then took off and cleaned the Throttle Body and attached sensors, such as AICV. No help. I then bought a used Throttle Body with all the attached sensors on Ebay, installed it this morning. Some help, it does not idle quite so bad, though still pretty rough, a little afraid to drive it. Car never stalls though. The car shows NO codes, and I have had 2 places hook it to their computers and run tests and look it over, zero codes, idling right at 700 and steady and neither place can find a thing wrong with the car.

It should be stated that any gas applied, immediately takes the shake away, and it shakes the whole dang car by the way, down the highway the car is perfectly smooth, it only idles rough when at a stop sign or stoplight, as soon as gas is applied it is very very smooth again.

I read your fixes, but please help point me in the right direction, I have already spent $450 on parts. I don't want to randomly buy parts till the problem is gone. Some help would be GREATLY appreciated.

Thank you for your time,
Ross

BlueEM2

iTrader: (1)

Go get a fuel system cleaning done somewhere. I'm not sure how much it costs nowadays but it's the next step to try and resolve your problem. Is your coolant low?

rossx34

Hi, I went to Jiffy Lube today and had my Fuel System cleaned as requested. Still having the same problem. What would be the next step?

Again, thank you for your time,
Ross

BlueEM2

iTrader: (1)

Take a video and post it here. You may be having some internal issues. How is your coolant level? Do you have a vacuum leak? Possibly a bad coilpack. Take a vid before you spend any more money.

rossx34

Alright, I am pretty busy due to work. I will make a video as soon as I can. I did have time however to drain the coolant and then refill to make sure it is at the proper level. And well now it is and I still have the same problem. One thing I should have mentioned earlier. It does not shake badly until it is warmed up. Once the temperature reaches about 1/3 of the way up, sorry to have to say 1/3 but the vehicle does not show degrees. Anyhow, the point is when first started and the engine is cool it does not shake. Is their anyway to test a coilpack to make sure it is bad?

Thanks again for all your help,
Ross

rossx34

Is there a way to check the Ignition Coils to see if they are bad or just not operating correctly? I know on older models with a distributor you could check the ignition coils with a multimeter, but the coils are different on my 2001 Honda Civic.

Thank you,
Ross

Dakota21601

That sounds alot like my car when i had som tb cleaner pooled up in the idle air control valve. U should take that apart and clean it or get a new one if that doesnt work.

sdaidoji

iTrader: (1)

did you try anything that is written here?

sdaidoji

iTrader: (1)

did you try anything that is written here at all before asking?

Camden

yes I did

sdaidoji

iTrader: (1)

ah, ok.
jus' tell us, we are not there to see what you did... sounds bad when you jus' ask without telling...

"goose"Jay

so after idk how efn long ive found my popping and slight misfiring culprate. another thing to add to the vacuum leak list, is the reservoir. It is apparently a common problem as well. Most people that have it dont even realize it unless they are under 2k rpms or at idle will cause a slight pop in the exhaust.

Camden

I checked my air filter, its good.

I removed my Vtec Solenoid (it was full of oil, is this normal?) I cleaned the solenoid out and made it look new and good.

I removed/cleaned the Vtec Solenoid head.

I tried to do my EGR valve but I had trouble accessing one of the bolts, going to pick up a proper wrench tomorrow for it.

I couldn't locate the PCV valve (I was going off the DIY maitence post by gearbox) Any tips/suggestions on helping me locate it?

Which sensor is the TPS sensor?

I ordered a new evap from honda today, it will be in soon.

I removed my throttle body and IAC valve (what a process) but thanks gearbox for the helpful instructions.
I managed to clean them both, ALOT of carbon build up came out of them, my car performs better now. When I hit the gas the reaction time is quicker.

I also reset the FI ECU.

All in all it was a good day, no CEL light anymore (but I think its because I reset the FI ECU??)

I was getting the AF precat CEL. I ordered a new sensor for it and I am going to install it tomorrow once it gets in. It was 220 bux but I'm sure its worth it.

The idle sounds/seems good now, pretty happy with it already and I'm not even done.

My only current issue is that the car shakes when I'm in 1st gear letting the clutch out. Usually from a stop to moving forward it will shake for about 3 seconds. It's worse with lower RPM. When I shift with about 2k RPM it's pretty bad, 3k RPM it's still noticeable but not so bad. It also shakes/vibrates when I shift from 1st to 2nd gear. Going from 2nd to 3rd I don't really notice anything.

"goose"Jay

how new is your clutch or pressure plate? That sounds like clutch chatter not a motor issue

"goose"Jay

or a worn trans mount check those as well.

ashokudu

For the shaking during shifting... you may want to check to see if you have any spark plus fouled... or not firing.... a dead cylinder will make it rattle... at low rpm and load... its a simple check... before u go digging deep...

ashok

SlimRisk

Alright this isnt really an idle issue, but it kinda is. I just got my throttle body back on and havent had time to do the idle relearn. the idle is great, but when its in neutral and i press on the gas just the slightest bit it goes from idling at 1500 to revving at 3000. and then when you take off the gas, it kinda sounds like a vacuum leak idle and it quickly drops to 1500. Its hard to describe i think ill post a link to a video

Seby05

It might have something to do with your flywheel being unbalanced. Think about it. The flywheel keeps momentum of the engine, so once in higher rpms, if ur flywheel is unbalanced, the centrifugal force will smooth it out.<--- This is just an opinion.
So either that or the clutch and pressure plate itself. Try this, get in ur car, and get to second gear hold it around 2500 rpms then hit the gas. Then do the same in third gear. See if ur clutch is slipping.<--- This is how a mechanic figured out that my clutch was f'd up on my jetta.
My point I'm trying to make is that the issue has to be at the contact point between the tranny and the engine.
Well good luck to u my friend, hope u figure it out before u spend too much money buying stuff

BlueEM2

iTrader: (1)

Hmm odd... Wrong spark plugs, wrong wires, the part the holds on to the spark plug may be worn out. Try replacing both.

civicinin

I have a 2001 Civic LX, and I'm getting error codes P0300-P0304 (all cylinders are misfiring). The only symptoms as far as I can tell is that it is idling roughly and it sometimes doesn't start as easily as it used to. Spark plugs are new. There isn't oil on them. Someone suggested changing the wires. I know I have coils, unlike the older Civics, but is it possible the wires connected to the coils need to be changed, either the ones circled in red or the ones circled in blue (see picture)?
Any help is appreciated. Thanks.

SlimRisk

You can't replace those. Make sure your oil was changed recently, along with a clean air filter, good fuel, and regular maintenance. I would seafoam your car

civicinin

Ok, thanks for the reply.

What is seafoaming? And what are the circled wires/plugs called? It is possible that they are the problem, even if I can't replace them?

SlimRisk

Those plugs are ground junctions. Highly unlikely they are the problem. http://ls1tech.com/forums/general-ma...-your-car.html

Do this and get back to us after your results. Make sure your air filter is clean first. And all of your coils look good

civicinin

Ok, thanks.

What will a bad coil look like?

SlimRisk

You'll know when you see it

civicinin

Not sure how helpful that's going to be, but ok for now.

civicinin

I took them out to do a compression test--numbers 1 and 3 are brownish. Does this mean anything? Cylinder 1 is on the left.

BlueEM2

iTrader: (1)

Nope normal, mine are the same way...

WKD DRGN

Is there a write up like this for 6th gen. civics or is it basically the same deal? My civic has pretty shaky idle at cold starts but is okay after the engine warms up and is okay when turned back on with the engine being warm. Spark plugs, cap and rotor and wires were recently replaced, within a few months and I try to buy the best aftermarket wise.