3-Series (E46, E90)Chat relating to the BMW 3-Series from 1999 to Current. Models include: BMW 316i, BMW 318i, BMW 318Ci, BMW 320i, BMW 323i, BMW 325i, BMW 330i, BMW 328 Ci, BMW 328i, BMW 325i/xi, BMW 330Ci, BMW 320d, BMW 330d, BMW 335d.
2 Sundays ago, car had a sudden loss of power, couldn't keep the RPM's up. Of course, power went way down. After wife got home, I decided to drop it off at the mechanic's.
I don't know if it's the fuel or not, but I could not keep it revved up. Had a very hard time getting it up hill. It was the same feeling as when you're right at the point of running out of gas without of course running out of gas.
Mechanic couldn't figure it out - no engine problem, no tranny problem. Mechanic I trust. They've been working on my cars for many years. He's worked on the BMW before. He tested the fuel and said that the E85 that the wife filled it up caused the problem. He drained the gas, flushed everything, refilled with premium and the car ran fine - until today.
Same symptoms. If I can get it going, it will go with some chugging here and there, but getting it to start moving is nearly impossible. It wants to die. Got it home after some real embarrassing moments stuck at the lights and running some lights just to get home.
Here are some things, related? I don't know. Got into the garage and could smell burning rubber, as in a slipping belt. Don't know if it is a belt or not, I'm just describing the smell. I've been hearing what I think are some bearings chirping. I know that last year the mechanic said that my A/C compressor was way on its last leg. Said that the bearings and clutch were on the edge.
About a month ago, I had the manifold gasket changed and brake vacuum line replaced. Haven't had a full tune up since I've owned it (2007). Regular oil changes with synthetic oil. Matter of fact, I had the oil changed after that last repair and prior to when this issue started up last week.
Ideas? Thoughts? Things to look at before I mortgage my house to pay for repairs?? I'm pretty mechanical. I do most of the maintenance on our cars, when time permits.
TBH I don't think the difference in the "octane" made it do what it did... This seems like a sensor (or sensors) issue at the engine, and could be just one or a combination failure !!
Have the Lamdas tested, clean any sensor you can get to - ICV, TPS, Cam and Crank sensors... As a start eh?
MAF and Throttle-Body would be good to clean while you're in the mood !!
Eso es todo! Please press the "REP" button if you are happy with your response/answer...
The engine light goes on only sporadically. Every time I put on my code checker, the engine light is not on and I get no codes. When I let off the gas, it dies. Hoping that there is an external way to test the O2 sensors. They are reasonably easy enough to get to so looking for ideas.
I have PocketScan Plus which I like a lot. Nice and easy.
Finally got my fault codes and probable cause per the Haynes BMW manual:
P0174 - Fuel System Too Lean (Bank 2)
P0171 - Fuel System Too Lean (Bank 1)
P0301 - Cylinder 1 Misfire Detected
P0302 - Cylinder 2 Misfire Detected
P0301 - Random or multiple cylinder misfires detected
What's not listed is P0150 through P0155, so hopefully I don't have an O2 sensor problem. I wouldn't look forward to changing them.
You can look at the previous posts in this thread to see my physical symptoms. I have the day tomorrow to do the work. I'm going to continue researching, but will gladly listen to any ideas you all might have.
Just my opinion I'm not a professional. I could be wrong. To me after reading your codes it seems like cylinder 1 and 2 are shuting down do to the missfires (computer turning of the effected cylinders). That could be your loss of power and idle problems. Is there any way you can look at your long and short term Fuell trims? This could help us determine what type of missfire you are having (mechanical, rich, lean etc.) If you can get readings at idle, 1,500, 2,500 you can see if your long term feul trim gets better or worse and that can point you closer to the exact type of missfire.
How do you go about looking at the long/short term fuel trims? I'm not familiar with that. I can barely keep the care running at any given time, so if it involves having the car running, that might be a little tricky.
Depending on your type of scan tool (Typically the more expensive the more capable). It should be able to have this function. You should have an option that says a "Live Data". it will give you information like RPM, Vehicle speed, MAF voltage, TPS voltage. so on and so on. You would just scroll down and look for something like (LTFT%) All scan tools are different so they might display something weird but most will show exactly that. You then will see a number like +3 or -25. This number tells you how much fuel is being added or being taken away. The closer to 0 the better. +10 your adding fuel. -10 you are taking away fuel. The Max number before you MIL comes on is + or - 30. If it hits that 30 number your computer can not compensate enough fuel for whatever is going on. Read the numbers at idle....then at 1,500 rpm, then at 2,500. Pay close attention if the number gets further away from zero (problem gets worse) at each engine speed, or gets closer to zero. (problem gets better). for example if the problem gets worse. This could be a sign of ignition problems. If the problem gets better this could be a sign of Mechanical (Vacuum, compression etc) problems.
Okay. Did some disassembly today. I sure enjoy working on my Bimmer. It's just engineered well. Anywho, I bought and used a can of MAF cleaner. I looked exhaustingly around and through the intake hose and found no cracks. I shut off the garage lights and shined my light around the housing and hose, moved it around reasonably and found no light coming through. Clamps are all tight.
I pulled the front O2 sensor. Is there a way to test and/or see a problem with it? You can definitely tell the direction of the exhaust flow due to light carbon build up, but nothing like when you look in your EGR on my other, older car.
Here's what's been done prior to this back in mid November after it was idling roughly:
-Air duct boot 1 & 2 replaced
-PCV update kit (don't know what this means exactly "update", better PCV I suppose)
-Valve cover gaskets
-Booster check valve assembly
The codes were 2882, 2883, 2974, 2973 at the time. Found leaks at the PCV, booster check valve and air intake boots.
No check engine light after these repairs. No codes.
A couple of weeks ago is when the problems worsened. See the previous posts. Plugs are worn so I'll replace those tomorrow. Doing research here indicates some easy things like vacuum leaks or O2 sensors. I just don't want to buy the sensors unless I really, really have to. They're expensive!
Anything else to check while I have it somewhat taken apart? M54 engine, automatic
ust my opinion. I am not a professional. I could be wrong.....
Of course there is a way to check the 02 sensor. All you need is a digital O-scope there only around $4,000 or more. LOL. I'm sure you are looking for the cheaper route with a DMM though. Not as convenient or accurate but it will work.
Okay so first let's understand what this damn O2 sensor is and works.
The O2 sensor senses oxygen in the exhaust. Tells the PCM what it sees. Then the PCM decides what to do with the Fuel, either take away or add (Fuel Trim).
When diagnosing driveabiltiy and performance. You have to remember that the O2 sensor "ONLY"...again..."ONLY" reads oxygen. (the light will come on later in your head about this key thing).
*Another side note. The PCM can only control two things in the whole damn car. Timing and Fuel. That's it. nothing else. When you simply things like this diagnosing starts to become easier. (Again that light will come on later).
Okay now we know what the hell this O2 sensor thing does. Let's talk about how it does it.
The O2 sensor like every other sensor sends a voltage signal to the PCM. Based on the amount of oxygen in the exhaust determines what voltage the O2 sensor sends back to the computer. The O2 sensor sends a voltage signal from 0 volts. to 1 volt back to the computer. The more oxygen the less voltage...(i.e. 0.2v running lean) the less oxygen higher voltage (0.8v running rich).
Have you ever heard of the 02 sensor getting lazy? What this means is that over the life time of the sensor it starts to slow down and can not read the oxygen content in the exhaust, and send information back to the computer quickly enough, for the computer to adjust fuel to keep it close to 14.7:1 (14.7 pounds of air to 1 pound of fuel).
Phew...getting close to testing I promise. But first......LOL
There are a few different type of 02 sensor. 1 wire...3 wire....4 wire.
1 wire: old school grounded through the body of the sensor (OBDI pre 1996). to test, ground one lead (voltmeter wire) attach other lead to the one wire from the oxygen sensor.
3 or 4 wire: Heated 02 sensor. (OBDII) Allows car to go into closed loop sooner. Two wires are for heating the 02 sensor and will have battery voltage at the connectors. To find which wire is which you have to check with a voltmeter. The actual signal wire you are looking for will read 0.4volts with the car off and the key in the on position (not starting). With a 4 wire sensor one wire is signal ground to the computer.
You can test the two extra wires (heater wire) with an ohmmeter. WARNING!! WARNING!! do not ever use an ohmmeter on a computer circuit. this could possibly damage your pcm. find the computer circuit first using a voltmeter or DMM switched to voltage so you know which wire is for the computer circuit.
Now compare your readings with specs. If it's out of specs the 02 sensor needs to be replaced.
Phewwww....now to testing.
The 02 sensor has what we call a cross count. It needs to fluctuate rapidly and repeatedly from 0.2v to 0.8v. This can only be done with a scan tool (not the best way but it works) or an O-scope (the most accurate). this is how you can tell if your 02 sensor is lazy. Check and compare to manufacture specs for your vehicle.
If the 02 sensor is always has a high voltage reading or a low voltage reading the sensor could possibly be either be defective or high resistance in the circuit (always low reading) or contaminated. or you just might be running to rich or to lean.
Pull out the 02 sensor and closely look for possible contamination.
Carbon build up (running very rich). Brown residue (oil). externally you could have mud, brake oil etc. coolant leaves white flakes.....on and on. Just like a spark plug it can give you a hint on whats going on inside your engine.
All in all that's why i would look at your fuel trim. reading your previous post to me kind of sounds like some type of restriction somewhere. maybe not enough feul (fuel filter). maybe not enough air. If you had an air leak (something the computer can't control). The car would respond better as you increased engine speed. Fuel restriction would cause problems when the car is under a load (like going up hill) it can't get get enough fuel with the amount of extra air coming in (throttle body open up more).
One thing that will help. How does the car act at IDLE?......how does the car act at cruise?.........and you already told me you can't go up hill.
Don't forget about ignition problems. If you have problems with the igintion the problem will get worse when engine speed increases as well. But to cancel out ignition. again we need to see how your fuel trim is doing. because missfires do not effect air fuel ratio ??????? save that for another day.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.