funny idle after valve adjustment

[russll5951]

i just did a valve adjustment on my 89 325is. after i was done the car had a funny idle that gently shook the car side to side a little and when i am at a light the check engine light comes on. once i rev up to go the light turns off. the valves were loud before i did the adjustment and now you can hardly hear them. should i go back and redo them or is there something else to look at.

[jlevie]

I would guess on an intake leak. You may have disturbed something when doing the valve adjustment. Or might not have tightened the clamp for the breather hose that connects to the valve cover.

[russll5951]

taking a look there is a small crack on the breather hose before the clamp, the side where the the valve cover is. would this be part of the problem?

[jlevie]

Could be.

You have a 19 year old car and it is a good bet that most if not every hose associated with the intake is either cracked or about to crack. You can play "20 questions" with the car over time hunting for and fixing one intake leak at a time, or eliminate all possibilities by replacing every hose as well as the dipstick o-rings and oil filler cap. In a like manner, new ignition wires, distributor rotor & cap, and new O2 sensor are probably needed (unless recently replaced).

[russll5951]

awesome thanks for the help. i will add these to the top of the list of things to do.:)

[redlinewins]

Your valves are to tight.

I did the exact same thing. After the first adjustment, valve noise was gone but idle was poor...idle as if the engine was missfiring. Checked the valves again and found them all to tight. I adjusted them again, after I was done, engine idle is now smooth and perfect. The valves are a bit louder than first adjustment but I understand this is normal on the M20.

[bimmerboy12]

Your valves are to tight.

I did the exact same thing. After the first adjustment, valve noise was gone but idle was poor...idle as if the engine was missfiring. Checked the valves again and found them all to tight. I adjusted them again, after I was done, engine idle is now smooth and perfect. The valves are a bit louder than first adjustment but I understand this is normal on the M20.

Very interesting. So you did adjust them to the right clearance, but they 'moved' tighter upon later inspection?

[mikekristine325ic]

Check for a leak in your valve cover. If you don't seal these off right, It will cause poor idling and a shitty throttle response.

[wagonizzle]

Make sure you tightened the bolts on the intake manifold support bracket that attaches to the valve cover. TWICE I have forgotten and gotten all that same stuff that you have been experiencing. Big ol vacuum leak.

[vtman05]

So did readjusting the valves make any difference or was it a vacuum leak?