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E46 325ci - Mystic Blue
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Discussion Starter · #1 ·

could someone familiar with obd fusion have a look at this chart for me,

been chasing a cold star miss fire - I have read through the fuel trims guide and have tried to find a vacuum leak however no luck, so I have turned to looking at the fuel system
can anyone see anything abnormal - I will get a fuel pressure test this week to confirm

I have swapped coils as its normally cylinder 4 - i had ruled out spark as when the car is up to operating temp it is completely fine, I'm leaning to fuel pressure regulator

any help would be appreciated
it wouldn't let me upload the .csv file so l can email if need be
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Run the 3 standard logs, post links here to the CSV files and we'll have a look.
 

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Discussion Starter · #5 ·
That log is not very useful. Looks like you were just driving around.

Do a 5-minute cold start log and post a link to that.
I will tonight when back from work try to get a better cold start, cursing and wot log for you
Thanks for your help in a noob on data logging

I did wonder what fuel status 8 meant as this morning it jumped up from 2 to 8
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Fuel status 8 typically means that the pre-cat O2 sensors have problems.

In that drive log, Bank 1 is looking rich (negative) and bank 2 about right.
 

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Discussion Starter · #7 ·
So couple days ago i swapped the coils round to eliminate them ( they are only about 6 moths old but nether the less) made no difference,
last night I tried changing the plugs around, 1 & 2 where nice and clean, 3 was a bit darker and no 4 ( miss firing cylinder) had fuel all over it, cleaned it up and left overnight ( miss fire ony happens when car is cold) started up fine this Morning. any ideas on the cause - is the injector leaking a possibility ? - baybe it was a bad connection to the coil plug and got fouled up
any suggestions on what to check will be greatly appreciated
 

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Discussion Starter · #8 · (Edited)
2003 325Ci
Mentioned this problem before, Switched coil pack and spark plug, misfire stayed on same cylinder. Checked for vacuum leaks on intake boot. Any suggestions on where else to check vacuum wise?

If I start the car and rev past 1700 RPM (while stationary) the car will idle fine. Only happens when left for several hours and is dead cold. Any suggestions?

The spark plug I pulled out stank of fuel. Could the injector be leaking?
If so, can I swap injectors to confirm without coding?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Usually chasing any misfire goes like this:
Swap coils, then spark plugs, then injectors.

The swapping is to see if any of the above actions (one at a time please) moves the misfire from the maleficent cylinder unto another.
Swapping injectors must be done with (possible fuel leakage) with care.
No special coding is needed.

Coding/indexing injectors for each cylinder, IS A THING. Albeit only on direction injection vehicles.
 

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Discussion Starter · #10 ·
Usually chasing any misfire goes like this:
Swap coils, then spark plugs, then injectors.

The swapping is to see if any of the above actions (one at a time please) moves the misfire from the maleficent cylinder unto another.
Swapping injectors must be done with (possible fuel leakage) with care.
No special coding is needed.

Coding/indexing injectors for each cylinder, IS A THING. Albeit only on direction injection vehicles.
Ahh ok thanks for that,

as mentioned before no luck changing coil or plug misfire stayed on cylinder 3,

I didn't think they needed coding but best to check - I work for Volvo and most of the ones we see need to be coded - although I think that's any modern car
does anyone know the size of the o rings - are the injectors prone to leaking or not heard much about it I assume the rubber deteriorates over time as it is a 19y/o car
 

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I have not reviewed this entire thread, but I would verify there are no vacuum leaks (smoke test), pre-cat O2 sensors are new/fresh and connected up correctly (they can be crossed), MAF sensor is operating correctly, fuel pressure is a solid 50 PSI under various conditions.

Before messing with the injectors I would do both compression and leakdown tests on all cylinders to see if there is maybe a burned valve, etc.
Reason being the following:
  • injectors on M54 rarely cause misfires
  • pulling the injectors out requires new o-rings and is a bigger job
  • if there is a cylinder issue, you want to know now before further diagnosing or parts replacement
 

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Discussion Starter · #13 ·
Hi all,
since my last post I have cleaned the idle control valve and replaced the fuel filter, i no longer have a misfire consistently every morning.

I now have a misfire intermittently - some times it will miss fire upon start up for up to 3 seconds or so other than this there is the odd hesitation when accelerating.

I did a compression test to make sure I had no major issues there before continuing to chase this issue, all cylinders bar cylinder 2 were 210psi at peak - no 2 was 190 peak,

I was happy there were all strong and mostly even, I have not managed to carry out a fuel pressure test as at work it is tested via a laptop (for the most part we only see newish cars being a main dealer there all the same brand)

iv pulled the freeze frame data and codes, I did a smoke test and couldn't find any leaks.

I will buy a fuel pressure tester but does anyone have any other suggestions ?
 

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I now have a misfire intermittently - some times it will miss fire upon start up for up to 3 seconds or so other than this there is the odd hesitation when accelerating.
the posted pics of diagnosis are not very helpful to solve this problem. Need to run the log to capture the required data.
Set up ODB Fusion:
Settings > Preferences >Logging>Logging Enable ON; >Logging trigger>Trigger at fixed sample time; Logging Control > Automatic; Sample Time> 1s; Select PIDs > SAE PIDs>fuel system1 status, fuel system2 stat, calculated load value, engine coolant temp, STFT1, LTFT1, STFT2, LTFT2, RPM,car speed,ignition timing,intake air temp,MAF,commanded secondary air, O2 volt B1 sensor1, O2 volt B2, senor1;
This setup will automatically log the data whenever the dongle is connected and the phone wireless is connected to the dongle. To end the log file, just click the Disconnect to end communication. To log more files, click Connect again to start phone communication which runs the log.
To post the log files, select Logs on main screen, then at bottom select Files, then choose the files to upload to Dropbox, then post the link for us to check the files.,
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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A relatively easy quick test for the fuel system is as follows:
  • At hot idle record all 4 fuel trims. Calculate the total fuel trim for each bank = short term + long term.
  • At steady 100 kmph (60 mph) cruise (use cruise control) record the 4 fuel trims. Calculate the total fuel trim for each bank.
  • If the cruise total fuel trims are significantly more lean/bigger (more positive) than the hot idle, then you likely have a fuel supply problem.
  • If the hot idle total fuel trims are significantly higher than the cruise, then you likely have a vacuum leak problem.
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Here is the OBD Fusion thread. It will help you set it up. The only advise I have is to use "PID Frame" as the trigger for logging.

 

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Discussion Starter · #17 ·
A relatively easy quick test for the fuel system is as follows:
  • At hot idle record all 4 fuel trims. Calculate the total fuel trim for each bank = short term + long term.
  • At steady 100 kmph (60 mph) cruise (use cruise control) record the 4 fuel trims. Calculate the total fuel trim for each bank.
  • If the cruise total fuel trims are significantly more lean/bigger (more positive) than the hot idle, then you likely have a fuel supply problem.
  • If the hot idle total fuel trims are significantly higher than the cruise, then you likely have a vacuum leak problem.
when totalling what values am I totalling the point where is is adding/taking the most fuel ? because mine is not steady at idle or should I be taking an average ?

warm idle

60 mph cruse ( there is a bit before where I was going to the motorway - obvs check vehicle speed to see where motorway starts)
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Both banks are rich in both logs. The cruise total trims are worse than the hot idle total trims. Your problem is common to both banks.

I suspect that you have blocked Cat's

You MAF looks to be under reporting in the hot idle log. It is showing 2.5g/s when it should be around 3.0 g/s. An under reporting MAF causes Lean conditions, which you don't have. It might be a good MAF with the reading being a clue for your main problem.

Rich conditions are caused by:
  • Too much fuel. Too much fuel pressure. Not a common problem on the E46.
  • Not enough air. A really dirty air filter etc
  • A faulty sensor fooling the DME into thinking one of the above is happening when it's not. MAF and Pre-Cat O2 sensors. The MAF may be good, lets park that for a minute. The O2's look to be switching normally. The range is a little odd/small/reduced. What fuel are you using? It looks like an Ethanol blend? What % of Ethanol?
  • Blocked Cat's. You did not log the Post-Cat O2 sensors, so I can't see if your Cat's are the problem. Do you still have Cat's fitted?

The general symptoms of blocked Cat's are:
  • Under reporting MAF values
  • Fuel trims that get richer the more load/rpm's put on the engine.
  • Poor performance
  • Misfires

For Post- Cat O2 Sensors:
  • Cat's in good condition have Post-Cat O2 voltages above 0.5V when at steady highway cruise. There may be the odd momentary dips.
  • If O2 sensors are switching between 0.1 and 0.8V, then they are following the pre-cat O2 sensors (Cat’s not able to treat the exhaust) and indicates struggling Cat's. This is the same for either narrow band or wide band Pre-Cat O2 sensors. Expect to start seeing P0420 and P0430 codes.
  • If O2 sensors are flat lined somewhere below 0.5V, you have one of these problems:
    • Faulty post-cat sensors
    • Blocked Cats. Check fuel trims, they are likely double-digit rich at this time. Do a before the Cat’s exhaust pressure test.
    • Fuel mixture problems that are so lean that it is being reflected in the post-cat O2 sensor signals
 

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Discussion Starter · #19 ·
Both banks are rich in both logs. The cruise total trims are worse than the hot idle total trims. Your problem is common to both banks.

I suspect that you have blocked Cat's

You MAF looks to be under reporting in the hot idle log. It is showing 2.5g/s when it should be around 3.0 g/s. An under reporting MAF causes Lean conditions, which you don't have. It might be a good MAF with the reading being a clue for your main problem.

Rich conditions are caused by:
  • Too much fuel. Too much fuel pressure. Not a common problem on the E46.
  • Not enough air. A really dirty air filter etc
  • A faulty sensor fooling the DME into thinking one of the above is happening when it's not. MAF and Pre-Cat O2 sensors. The MAF may be good, lets park that for a minute. The O2's look to be switching normally. The range is a little odd/small/reduced. What fuel are you using? It looks like an Ethanol blend? What % of Ethanol?
  • Blocked Cat's. You did not log the Post-Cat O2 sensors, so I can't see if your Cat's are the problem. Do you still have Cat's fitted?

The general symptoms of blocked Cat's are:
  • Under reporting MAF values
  • Fuel trims that get richer the more load/rpm's put on the engine.
  • Poor performance
  • Misfires

For Post- Cat O2 Sensors:
  • Cat's in good condition have Post-Cat O2 voltages above 0.5V when at steady highway cruise. There may be the odd momentary dips.
  • If O2 sensors are switching between 0.1 and 0.8V, then they are following the pre-cat O2 sensors (Cat’s not able to treat the exhaust) and indicates struggling Cat's. This is the same for either narrow band or wide band Pre-Cat O2 sensors. Expect to start seeing P0420 and P0430 codes.
  • If O2 sensors are flat lined somewhere below 0.5V, you have one of these problems:
    • Faulty post-cat sensors
    • Blocked Cats. Check fuel trims, they are likely double-digit rich at this time. Do a before the Cat’s exhaust pressure test.
    • Fuel mixture problems that are so lean that it is being reflected in the post-cat O2 sensor signals
I really appreciate you taking the time to help me,

Yes depending upon what is available it will normally be super unleaded which in the uk is 5% ethanol however currently it has a tank of normal unleaded as its all they had, that is 10% ethanol.

still on stock headers so cats are still there, I will tomorrow log again and enable the post cat sensors for you to have a look at. I take it that is just o2 bank 1 sensor 2 & bank 2 sensor 2
is there anything else I can log to help you identify if it is the cats? would a log pulling through the rev range at a normal pace help to see if the trims continue to get richer as I increase rpm's ?

The o2 sensors I doubt have ever been changed car is now on 160k, - re the MAF it is running a "cold" air intake - issues were still the same on the stock airbox as I did switch back and still had all the same issues.

I do get intermittent misfires - mainly upon start up however it is not a bad as it once was before I could start up and run on 5 cylinders for about 20 mins ( not by choice I had to get to work)
its nicknamed the straight 5 and a half at work, after cleaning the idle control valve/replacing the fuel filter it improved drastically now maybe 5 seconds at start up when cold and will idle fine - odd hesitation every now and again
 
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