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1996 328is misfire problem. I really need some help.

12K views 69 replies 8 participants last post by  drivinfaster 
#1 ·
So im showing random misfire, misfires in cylinder 1, 2, and 3. When im driving, the car will run perfect. Smells a little rich. Then it will start hesitating, when I get on it, it will hesitate at low rpms, then clear up at high rpms. When i come to a stop the idle will drop low like its going to stall out, then come back up.. I can feel when it random misfires, idles rough, sputters when idling and accelerating and feels sluggish. If I shut the car of for about 30 seconds and start it again it will run fine. Ive replaced the spark plugs, no oil in the wells, replaced coil boots, coils tested fine, replaced cam sensor, replaced a cat, new ccv valve and breather hose. Replaced the fuel filter as well. Im at a loss of why it keeps doing this. Anyone have any ideas? Im tired of replacing things that dont fix the problems.
 
#3 ·
Reader showed random
P0300 random misfire
P0302 cylinder 2 misfire
P0303 cylinder 3 misfire
P0455 evap leak
I had an O2 sensor code thats a new one.
I think P0135
The reader just said "oxygen sensor circuit bank 1 sensor 1"
Now I suspect the o2 sensor. Ive never had that code before.
 
#7 ·
Harry, his original post indicates he's replaced the cam sensor already....

OP, there's not a good test for either the O2 or the knock sensors. Usually when you get an O2 fault the sensor does have an issue, so I think I'd replace that one first.
 
#11 ·
well, yeah, it is possible to test, but you would need a power graphing meter at a minimum to be able to do so.

oh, yeah,...and know how to use the pgm too,....;)

there is also a power balance tester for testing the flow of the injectors (i haz one) that is used in conjuntion with a fuel guage. lengthy test to check for flow, but a pgm could also be used here to graph the voltage of the injector to check for a faulty circuit.

however, by the description, i would look at the crank sensor. this is the input to the dme that tells it when the engine rpm falls, and the cam sensor identifies the cylinder.

since it is an intermittent condition, i would suspect a poor connection, bad ground, or a charging system that is going wonky.

the dme reads nothign but voltages, so when that goes weird, the dme will respond accordingly.

a pgm could also be used to check the crank signal (which should be a nice sharp square wave signal on obd2 vehicles), as well as switch over to dvom mode and be used to do a voltage drop test on the circuit.

cost?? anywhere from 5-1500 bucks depending on where you get one. the otc perception is what i have, under the mac brand. nice unit. almost 14 years old now. if you look into getting one, go with at least a 2 channel unit.

df
 
#13 ·
So I was looking at where my crank sensor is suppused to be, under the vanos behind the engine fan. And its just an empty hole. I can see where its supposed to be, but nothing is there.
 
#17 ·
Well the reason why I say the injectors is because of the rich fuel smell he smells after the engine is acting up. So either the injector is sticking open, or the connection to the injector is not good. Usually my first guess with a rich smell of fuel and poor idling starts with the injectors.

I know SC Jon is having the same issue with his car. He needs to have his ECU re-flashed to remedy his issue.
 
#19 ·
Someone correct me if I am wrong, but I think the platinum plugs can be finicky sometimes (bad idle?). Aren't the two prong copper NGKs the plug of choice?

The P/O of my car put in BMW long life plugs (I'm assuming that's the factory plug) and the car has run like a top since the day I bought it. The reason it got factory plugs was because the P/O brought the car back to the garage due to poor power and bad idle after getting new plugs.
 
#25 ·
Fresh batch of codes.
P0130 bank1 sensor1 circuit malfunction o2
P0170 fuel trim bank 1
P0300 random misfire
P0302 cyl2 misfire
P0303 cyl 3 misfire
P0173 fuel trim bank 2
P0455 evap system leak detected
I have become totally lost
i have written out the definition of the codes for you.

all but the po455 seem to be related, as they are fuel trim and misfire codes.

you may have a faulty o2 heater circuit relay for the po130, and with the po170/173 i need to know if the fuel trim is at the positive or negative fuel trim parameter.

a negative fuel trim indicates that additional fuel is getting into the system (cyls 1-3 are bank 1), where a positive fuel trim indicates the dme is trying to richen the mix.

if the evap leak is from a canister purge solenoid that is open, and it is drawing a vacuum on the fuel tank, then that could be related to both a rich condition, fuel trim out of parameter (on the neg side), as well as possible misfire codes.

if you are running 4 prong plugs, i would suggest putting an oe style back in. not a big fan of that sort of design. similarly with the bosch +4's,....which are garbage in most cases.

as was stated, check for rips in the intake boot, cracked vacuum lines, and post a pic of the 'spatter' that you mentioned.

possible other causes could be a maf (will set o2 codes and affect fuel trim), faulty dme, improper fuel pressure, faulty injector(s), ccv system.

df
 
#26 ·
Ive had P0455 has been there since I got the car. The code only shows when I get below a quarter tank. I replaced all the ccv system. I checked for any leaks, but found none. Ill snap a picture of the injectors in the morning.

The part numbers for the o2 sensor is the same for all 4, could I swap the sensor throwing a code with a post cat sensor to check?
 
#27 ·
no, not necessarily. it depends on *why* the code was set. if the code was set due to a dead/dying sensor, then you will wind up throwing catalyst efficiency codes by swapping it out with a secondary o2 sensor.

if it was set due to the dme being unable to curb in the fuel trim, even a new sensor will do nothing to get rid of the code.

you need to look at the fuel trim numbers in order to be able to determine this. this info should be displayed as 'ltft' and 'stft', long term fuel trim and short term fuel trim. long term is the parameter that will set when fuel trim is beyond factory specifications.





df
 
#28 ·
Once again I'll mention that I had everyone of those codes at the same time when I was given my car. I had all kinds of vacuum leaks. The boot , hoses, you name it. I can almost assure you that a big vacuum leak is your problem. Blow some cigar smoke thru your brake booster hose and watch where it escapes from. Then sit back and enjoy the cigar knowing you found your problem. In my mind, a vacuum leak is the only thing that can cause your issue, after knowing all the parts you changed.
 
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