M20 runs rough like it's got a lumpy cam

[CENTURION]

all electrical spark components were replaced as well. Sorry, forgot to mention that

[Ceeker]

my m20 had the same issue. now... I changed my o2 sensor, had a valve adjustment, replaced water pump with new, except the injectors were replaced with non v m50 injectors and ecu was not reset. so in the end my motor seized and cylinder 4 or 3 rod broke from the piston. soo... that is what you shouldn't do. hopefully this helps and guides you towards the proper repair. GL

Sounds like two separate issues. These motors r known to b bullet proof. low oil or hydrolock have been my experience for motor to sieze. Breaking a conn rod? Wow. There was something else secondary going on with ur motor. Sucks sorry to hear that.

Only risk im up against is eventually burning the valves if they r a bit tight.

Going to adjust the valves again and clear any codes on the dme.

Thx for the advice.

[Ceeker]

well, replaced the 02 sensor; car at idle - idle pulsates a bit.
gonna reset the dme and maybe swap out the ICV to see if this changes anything.

[Ceeker]

well, replaced the 02 sensor thinking it would fix the rich burn; car at idle - idle pulsates a bit.
gonna reset the dme and maybe swap out the ICV to see if this changes anything.

[FreedomM3]

It amazes me so many people with the same problem and no one has a solution. I have the same issue.

[Kershaw]

Ceeker, check that the bitch tube is seated properly. Itb really sounds like you missed something. Double check everything below the manifold, stuff down there is easy to miss. It really sounds like a vacuum leak.

Freedom, have you checked everything over for leaks?

[Dirty325ix]

It amazes me so many people with the same problem and no one has a solution. I have the same issue.

because 99% of the time its as simple as vacuum leaks but for the most part people don't seem to want to spend money to do a smoke test so they just throw parts at it(im guilty)

then the other 1% could be anything electrical but in general nobody gives enough information to properly diagnose the problem(voltages and such)

if you have any problems with your m20 check this thread out

http://www.r3vlimited.com/board/showthread.php?t=364705

itll solve almost every problem and I believe it was posted because of the repetitive nature of these "m20 no start" and "rough idle" threads. For the most part everything that can break on your car has already broken for someone else and the fix has been documented somewhere on this big oll interwebz

that being said when ever I have a problem with my car its straight to the forums with a stupid but for the most part its just to think out loud and it seems people get a tired of seeing the same questions week after week, so you will get less responses

moral of the story? idk im just board at work
so your :welcome:

[Ceeker]

As suggested: I am going to re-adjust the valves. I believe they are a bit tight and from what my bmw tech friends tell me they run better if they are adjusted a med .10- cold- not tight nor too loose.

thanks for everyone's input. much appreciated.

[Ceeker]

Ceeker, check that the bitch tube is seated properly. Itb really sounds like you missed something. Double check everything below the manifold, stuff down there is easy to miss. It really sounds like a vacuum leak.

Freedom, have you checked everything over for leaks?

I know I installed that oil tube properly because I used silicone to make sure it seated well with new o -rings. sometimes the spring tension isn't enough to move it into place so it does need a little help. Experience has taught me well...hahaha...

missing something can definitely happen but what I gather I missed was re adjusting the valves. my suspicion is they were adjusted a bit tight.