need help please!!!!

[pauliefireballz]

i have a 98 323is. i started driving my car this morning, and there was absolutely
no acceleration....the intake in my car was making a very high pitch noise. i could rev the engine normally in neutral.... but when i was in gear it wouldnt rev past 3000 rpms.....i think i might of bent some valves or somthing....and i think its only running off a few cylinders.....would anybody no what this is???? if sooo what would the cost be??? please help me

[jtspells]

Auto or 5-spd?

[Manolito]

I am focusing on the high-pitched noise because 90% of the suspects would not cause a high-pitched noise, and I am operating under the assumption that the noise is directly related to the problem. Can you describe it?

First - the inexpensive stuff (hope springs eternal). Look carefully at the plastic tube that leads from your mass airflow sensor up to the throttle body. Is it cracked or disconnected? Take it off if you cannot see beneath it. A hole in that tube would cause intake noise and power loss.

Second, could the noise you hear be the cam chain grinding on the inside of the engine case? If so, you have lost a tensioner or follower or something. Sorry that I have never had one of these open, so I don't know how the cam chain is configured. If that may be the case, DO NOT drive the car or run the engine any longer. You could already have serious damage and it can only get worse if you drive it.

[pauliefireballz]

i found out today its definatly the cats....i have a five spd

[Manolito]

Cats - catalytic converter? I am trying to imagine how a plugged catalytic converter would cause an intake noise.

If your catalytic converter is plugged, you have something else going on that caused it. Does the car consume oil? Has it been running rough for some time?

[pauliefireballz]

i always thought there was a hole in my exhaust.......i used here it kind of rattling.....my mechanic told me today it was just the catylitic converter. he is a certified bmw mechanic.....but it really seems like something more than just the cats. some one else told me it is in limp mode???? but anyway like i said...i'll start up the car and there is no problems....but when i start driving my intake sounds like its pulling through a ton of air.. it takes me about 1 minute and a half to get up to 58 mph.....and thats all it will go it wont go past 58 mph?????.....i dont know.....please help iam losing my mind

[pauliefireballz]

some people are also saying i bent valves.....but then my mechanic said i didnt

[Manolito]

Bent valves would not let the car idle normally or rev in neutral.

A plugged exhaust (cat) would let it idle but not rev up under load, and would definitely limit top speed, but should not cause unusual intake noise, at least, not with a stock cam. Normally, the simple test for a plugged exhaust is to put your hand at the exhaust pipe opening. If you can feel the individual bursts of exhaust at idle, it is OK. If it is just a smooth flow of air, it is obstructed. If you have a leak somewhere such that the exhaust is exiting before it gets to the muffller, then this test won't work.

Limp-home mode is when the computer is not getting one of its critical signals, such as oxygen sensor or mass airflow sensor or temperature, or the signal that it is getting is out of bounds. It goes to 'average' settings for timing and injector duration such that the car will run and get you home, but it doesn't run very well and won't develop maximum power. However, your description of the symptoms suggests something more serious than limp-home mode is going on. If the engine is in limp-home mode, the check engine light will illuminate, unless the light is not working. Does the check engine light illuminate with the other warning lights when you turn the key to the on position?

[pauliefireballz]

the check engine light is on

[Manolito]

Follow these directions to read out the fault codes and see what you can find out.

Remember that fault codes do not necessarily tell you what is wrong with the car, they can only tell you what the computer THINKS is wrong with the car, based on the readings it is getting from the sensors. At least, it points you in the right direction.

Pelican Technical Article: Reading BMW Fuel Injection Fault Codes