Rough idle - yes I searched
 

As the title states I've read all that I could on the rough idle but still not 100% what im after. As you can guess my car has a rough idle but to an extent also continues as I drive. I can barely feel it as im driving. Almost like a slight shimmy or something. As I sit and idle its an in and out rough feel. Ny finace says she dosnt notice it but I do. The hotter it is outside the less it does it. This morning at around 70° it was slightly more noticable than this afternoon at around 90°. Just seems smoother as it gets hotter outside. Ive checked all hoses and replaced the plugs. Havnt gotten to the wires yet since im broke paying for my wedding. Ive pulled the PCV valve and cleaned it inside to where it was spotless. Still nothing has changed. Any ideas would be appreciated since I will be taken the 318 on my honeymoon and dont want to be stuck on the highway. Thanks in advance!!

EDIT: What im asking is that if you have had the exact same problem and replaced 1 certain sensor to solve it or made an adjustment please let me know. I hate to go and dish out a bunch of money and replace different things when all I needed was one item.

EDIT: Also, the previous owner was only runing 87 octane. I switched to mid grade and have only been useing Shell gasoline since all the others around here are garbage and stalls out other cars including my fiances. I put some seafoam in the gas in hopes of cleaning any injectors that might be clogged.

I'm no expert but I kinda had a rough idle issue too. Not as you describe but nonetheless, I check my spark plugs to find oil with every plug, after changing them, the idle was smooth as can be. Now, it starting to act up again because I haven't solved the issue (valve cover gasket). Plan on doing that this weekend.

Hope that helps a little!

LOL I was just reading about the oil on your plugs. My car is not leaking oil and when I changed the plugs the old ones were clean. They were worn but useable. I just make it a point that when I buy a used vehicle that I change all fluids, plugs, wires, ect. I just get real anal about how my cars run and this is driving me crazy. It should be smooth and purring like a kitten!! Thanks for the heads up though.

Vacume leaks.

Take the rubber air tube between the throttle body and the air flow meter off, and clean it, you'll likely find little cracks in the bellows, its like 29 bucks at the dealer and raises hell when it wears out.

Dave

That was one of the first things I checked and I did find some cracks. I used a rubber epoxy and sealed them up for the time being. Guess I should look at replacing. Thanks.

Anyone else? Ideas? New boot was not the issue.

There's a tiny vac hose that makes a 90 degree downwards comming out from a tube from the upper intake in the front. It's so small that perhaps you may be missing it ot it got unplugged.

Thanks ti. I will go and double check that!

check the hoses and check the belts, my belt went bad and it gave an impression of rough idling when it was just really a noise making me paranoid lol

Thanks for the response. Belts were checked first thing and its not a sound. Its an actual feel. I believe I might have found it. There is a hose running from the back of the upper manifold to the idle controle valve that is cracked. I didnt catch it on my first inspection since its hidden pretty good. Local BMW dealership says they will have the hose for me by Monday. Guess I will see if its the culprit once it arrives.

Just a heads up to those not in the know. Im sure all the verterans here have either delt with it or know about it. I found that one thing and it was a hose that runs from the back of the upper intake manifold directly underneath it to the idle controle valve. I have the M42 if your wondering. Takes less than an hour to replace if you know what your doing. Just remove one end of the hose that runs from the PCV valve, remove your intake boot then your upper intake manifold. Try not to lose or damage your IM gasket or just replace it while you are there. You dont have to disconnect everything from the IM. Just move it enough so that you can get under it. Be sure to put everything back and dont over torque your bolts. That simple.

see if this will work

http://forums.bimmerforums.com/forum...d.php?t=454501

Nice link. Thanks!

did mine ....

changed the two hoses connecting to the icv
changed the hose from the engine valve cover to pcv valve
sprayed the icv with throttle body cleaner and lightly brushed

engine does run smoother...

I already replaced the boot with a new one. All it ended up being was a hose running from the back of the upper IM running to the ICV. After I fixed that it was fine. I went back yesterday and pulled the ICV and cleaned per the suggestion above for good measure.

I tried all of these on my M42 and am still getting a rough idle and low power on acceleration. I did notice that if i open the oil filler cap the idle steps up and gets real smoothe. I tried cleaning the PCV valve, should i just replace it?

I have a similar issue on my 95 318. i took out the icv and cleaned it, put it all back in and its worse than it was before. a terribly rough idle

Ruddman - Not 100% sure of what to tell you on that one but its worth a shot.

Craig - Check and make sure you didnt split one of your hoses or cause one to crack. Did you let the ICV dry before you put it back? The hose that runs from the back of your upper intake manifold to the ICV could be the culprit.

Still Running rough, error code 1222. the first thing i did was change the plugs, just checked them and they look like they are coated in soot. looks like a new air filter and cleaning the O2 sensor is next? any thoughts?

Code 1222 is an Oxygen sensor code. Means its running to rich/lean. Just to be on the safe side though i would def go through and check all your vacume lines for any leaks. Also go through and check the rubber boot that runs from your MAF to your throttle body. Look in between the ridges for cracks and such. Other factors can cause that code such as bad O2 sensor, fuel pressure, injectors, AFM, in the end just about anything that that could mess with the aif fuel mix. Start small and work your way up. Lots of times the smallest thing over looked can give you the biggest headache.

I am going to clean it again tomorrow and this time with more time to spare to let every thing dry out but I found that the plugs the guy put in before me were platinum! What an idiot! Quickly replaced them with model specific plugs and idle is semi cured.. Only problem now is as the sun sets in the evening and I start my car at night.. The rough idles back any ideas why that may be? I don't think it likes the cold and am afraid of the coming winter how it will be running any suggestions greatly appreciated

At a loss?
 

:confused:New air intake, new Pcv valve, cleaned ICV, checked all vacuum hoses and rubber boots, changed plugs, cleaned O2 sensor, cleaned AFS. Still running rich, poor gas milage 60%, poor accelleration. it feels like it is runnung on 3 or less cylinders, rough idle and no power. Number 4 plug looks a little oily, its the only one though. Still error code 1222.
Whats next?

Could it be my exhaust system? There's a rattleing coming from my upper exhaust manifold the catalytic converter could this affect my idle?

Also getting code 1263 the purge valve and am wondering how this affects everything or is it giving me a faulty code?

I seriously doubt that this has anything to do with your problem, but it's easy to check, so.... Is your engine warming up to the correct temperature? The temperature needle should move to the "12 o'clock" position and not move from there until you turn the engine off.

If the thermostat is bad or going bad, it can cause the engine to run cool, which will cause it to run rich. That was the first issue I had with my car after I bought it, but I don't recall it running rough.

Temp guage stays at "12 o'clock" runs rough cold or hot.

Dont k now what to tell ya gents. Try running some seafoam in your gas and see if that helps. Might have some crap in your injectors.

is it a bad idea to remove, clean and re-install the injectors? would a closed ICV cause the engine to stall at idle and seem as if the engine were running on 3 or less cylinders? (very low power)What is the problem associated with Platinum plugs?

I'd actually replace the O2 sensor and the PCV valve. Also check the vacuum lines to the injectors.

It could also be the MAF, I dealt with a huge headache with mine and it ended up being the MAF. What you really need is a ODB-2 scantool so you can actually look at the sensor inputs to the DME.

are there any vacuum lines that i may be missing? I have checked all lines that can be seen with the upper IM removed. the idle picks up when i open the valve cover cap. could there be some gunk plugging something inside?

It should pick up, taking the oil cap off creates a vacuum leak, especially if the pcv valve is bad. Again, it really should be replaced. It's pricey, but it'll stop all that oil getting sucked into the intake...

not really anything else to check. You really need to get a scanner and look at the sensors real time to diagnose the problem.

the PCV valve is new

ah.


well, it's pretty much down to checking the sensors. Without knowing what the motor is seeing, not much more I can suggest.

seafoam in gas helped alot.. thinking about doing through the intake any suggestions?

If the seafoam in the gas helped then it could be several things. First thing is after you have run the gas that has the seafoam I would change your fuel filter since any gunk that was broken lose before the filter can get trapped in it. If you want, fill your tank and run another can for good measure first. It means you could have some crappy gas and needed the higher octane or you just had some blockage. I use to go for the cheaper gas but started running Shell gas and have noticed an inprovement. Around here its the only thing my wifes car will run on. Its a pontiac but I dont judge. I lover her anyway.
I would not recommend running the seafoam through the intake. If you feel like you want to run it through the motor then you will need a friend. If you do this you do so of your own free will and im not responsible for anything negative that might occur. Find a nice open area away from neighboors and other cars. When ever I have done this to my cars I always disconnect the hose from the brake booster and have a friend start the car. It will try to stall so he/she will have to feather the gas to keep it running. Place the hose into the seafoam can and let it suck it down. Once done cut car off, reconnect hose, and let it sit for a bit. I usually go 30min to 1 hour. After it has sat start the car and let it run. You will then start to notice a lot of white/gray smoke coming from the exhaust. Dont panic its just the seafoam burning off with the gunk it broke lose. DO NOT drive down the road this way. It may take some time but eventually it will all burn out. If you motor has high miles I would hold off on doing this due to the fact that over time some of the build up actually acts as seals and keeps things from leaking. Your car your choice.

Would it be a bad idea to use it in the oil as well?

I've never run it in my oil so I couldnt tell you. I know that there are some people who have. I feel it would be the same result if you have a high mileage engine when it comes to build up acting as seals. I would google it if I were you and see what you can find out from others before actually doing it.

New PCV Valve, New O2 sensor, Checked all vacuum lines, new plugs.
Cause of the problem? Ignition coil. Problem solved!

thanks ill assume maybe thats a good next step for mine as well

Great thread and responses! I've been experiencing similar issues with my 95 ti sport. Gonna explore possible problem points. Thanks!