318i losing power - United Bimmer Community

**Bullishone** · 03-06-2010, 11:21 AM

Hello,
I have a 93 318i and I have been having some issues with the car hesitating and losing power. A bit of history on what was recently replaced is fuel pump, battery, alternator, and fuel filter. Prior to a few days ago the problem only started if there was a bigger load on the car(rear defrost and blower was on high)...now it is happening even without anything on. The car will start to lose power but if you step on the accelerator it will pick up speed. I brought it to a mechanic and he said the code(2001) is coming up (o2 sensor is too rich). I did replace the o2 sensor months back.

Any help will greatly be appreciated.
thanks,

**David Mc** · 03-06-2010, 03:56 PM

Make sure that none of the vacuum hoses were damaged or left disconnected when the alternator was replaced and check your spark plugs. Basically they are more likely to fail under load and will result in incomplete combustion, which the O2 sensor will see as running rich. It is not uncommon for an engine with bad spark plugs to idle like a clock, but it will cough and sputter under hard acceleration or heavy load.

**Bullishone** · 03-07-2010, 01:06 AM

Thanks for the info David Mc! I'll check it out and let you know. Thanks again!!

**Lamdog** · 05-29-2010, 12:19 AM

Hi Bullishone, I have the same exact problem. Did you ever get it resolved?

**kazamali** · 06-04-2010, 01:41 PM

If the o2 sensor was reading rich, then your problem can be caused by

1. Bad MAF (over-reporting the amount of air in the system)...but not sure if your year uses that

or

2. Leaking injector. It's possible that an inner injector valve seal is worn and is consistenly leaking fuel into the cylinder causing it to go rich. The only solution is to replace the injector.

3. Air restriction somewhere in the intake path (filter, Throttle Body...)

**Bullishone** · 06-04-2010, 09:13 PM

Quote:

Originally Posted by Lamdog

Hi Bullishone, I have the same exact problem. Did you ever get it resolved?

Hey Lamdog,
No I still have the same problem just not as often. It seems that when the weather got warmer the car ran better. I think I am going to follow kazamali's suggestions and check the injectors because there was one time before the hesitation started, when I went to start the car and it cranked very fast like I blew the timing chain and the car didn't start. I took it to the mechanic and he said he removed the spark plugs and squirted some oil into the cylinders and the car started. He thought that for some reason that the cylinders got washed out with gas. So it makes me think I have a problem with one of the injectors.

Let me know how you make out.

**gldfshkpr** · 06-08-2010, 11:08 PM

Could the timing chain have jumped a tooth?

**Lamdog** · 06-11-2010, 11:21 AM

Quote:

Originally Posted by Bullishone

Hey Lamdog, .... He thought that for some reason that the cylinders got washed out with gas. So it makes me think I have a problem with one of the injectors.

Let me know how you make out.

Bullishone, no luck for me so far. I've just changed out the fuel filter and replaced both the front and rear O2 senors. Still has the problem. I am busy this weekend but will likely work on it again the following weekend. The car runs fine 95% of the time, it's dies on me and RPM drops, once in a while, but it never really dies out.

I didn't have this problem until I changed out the MAF and crank position sensor, becuase they were on the check engine code. My mechanic sugguests that one of those units may be bad ... being that I didn't have this problem before. Kind of at a lose now where to go from here ... other than check my vacuum hoses and fuel injectors ...

**Lamdog** · 06-17-2010, 10:32 AM

Guys, I believe I have finally got this fixed. The culprit (at least for my car) is the camshaft position sensor. Yes, I've changed it (and a bunch of other stuff) and the problem persisted ... so finally I took it into a shop. The guy opened the hood, took one look at it, and said it's your "aftermarket" camshaft position sensor that is causing the problem. Initially I had a hard time believing it, but ultimately let him work on it.

Changed out the aftermarket sensor (which costed $55) and put in an OEM from BMW (which costed $116!!!) and the car runs like it just came off the assembly line!!!

Here a rule to go by, any electrical part you're replacing ... pay alittle extra and get OEM!!!

Good luck with the fix!