[=C=]

Hi Guys,

I need some help with reading and understanding the datalog below so that I can better understand what is happening with the car and the potential issue/troubleshooting required.

http://www.datazap.me/u/vsashav/02-s...og=0&data=3-14


The issue:

- Engine and car vibrates and shakes very rough, never experienced this before. Pull started when accel pedal at 80~%, rough vibrations and shakes occurred and I eased off the throttle ie 60~%.

I haven't even reached more than 4k RPM at this stage...



Brief summary:

I originally had a misfire on Cyl 1 after tune (Cobb AP, ST Sport Stage1).

New - All 6 spark plugs replaced with Bosch.
New - All 6 coils replaced with original OEM
New - 3 index 12 fuel injector's replaced for Cyl 1, 2 and 3.
New - Both stock Turbo's replaced by BMW (approx 6,000 km's on them).


Cobb AP returned 3 error codes (Misfires on Cly 1, 6 and more Cyl's).

P23CD (Cly 1 misfire)
P29D2 (Cly 6 misfire)
P26CC (More Cly misfires)


I suspect Cly 1 is still an issue, not sure why Cly 6 came up and More Cly misfires probably because it went into Limp Mode. Had to restart the car to clear and drive back to normal.


Car Mods:

- Stock airbox filter replaced with K&N High flow filter.
- VRSF Charge Pipe with Tial BOV.
- BMS OCC.
- DP's currently not installed (waiting to resolve this issue before adding any more mods).



Appreciate the help in advance!

[titium]

you need to log AFR bank 1 and 2 as well as high and low pressure fuel rail pressures.

Also add in fuel trims both short term and long term.
but from that log it looks like the DME is shutting down cyl due to misfires, this is the vibration you are feeling - running on less than 6 cyl.

[=C=]

I noticed the COBB didn't log all the default data so I will have to re-do the log again.

Currently back to stage 0 (stock map) in order to drive the car.

[=C=]

Issue now started occuring with stock map but very hard to re create at normal driving conditions. You would have to try WOT in 3rd to get the same symptoms but the sympomps are not as BAD or as obvious when tuned.


Could the following be the issue even though no error codes displayed:


- boost leak?
- leak in PCV valve / plastic connection ?
- carbon build up intake valves?

[jwebb335xi]

Originally Posted by =C=

Issue now started occuring with stock map but very hard to re create at normal driving conditions. You would have to try WOT in 3rd to get the same symptoms but the sympomps are not as BAD or as obvious when tuned.


Could the following be the issue even though no error codes displayed:


- boost leak?
- leak in PCV valve / plastic connection ?
- carbon build up intake valves?

Could be lots of things, but you may want to look at the traditional issues. Remember, fuel and spark make fire. Rechecking all plugs and coils may make sense. Also, as someone noted above, you want to look into fuel delivery. It could be that your fuel pumps can't keep up...... doesn't sound boost/leak related as you'd likely see different code (30ff, if I recall correctly).

[=C=]

Originally Posted by jwebb335xi

Could be lots of things, but you may want to look at the traditional issues. Remember, fuel and spark make fire. Rechecking all plugs and coils may make sense. Also, as someone noted above, you want to look into fuel delivery. It could be that your fuel pumps can't keep up...... doesn't sound boost/leak related as you'd likely see different code (30ff, if I recall correctly).

Spark plugs and coils have already been replaced with new parts which cost me a lot already and it hasn't fixed the issue.

I don't like the exercise of guess work to replace parts will-nilly that are functioning OK just because I think maybe it's this or maybe it's that.

[limitdown]

If this issue is still showing up in cylinder 1, even with new plugs, coils and injector, then it's possible you have problems with one of the fuel pumps.

You'll need to do a WOT pull in 3rd gear with the pedal to the metal 100% of the time to red line, and log the low pressure fuel psi, and also the high rail pressure. In your log, you let off on the pedal after 3k rpm. Your LPFP shouldn't dip below 60psi and HPFP rail pressure shouldn't go below 2k psi.

It's also possible that one or both pre-cat O2 sensors are dying. Sometimes these don't give codes until they're actually dead. I've changed both upstream sensors 2 times already.

Also check that your plugs are gapped correctly. If you have single-pronged plugs like 5992/95770's, they must be gapped very precisely to 0.55mm/0.022inch . I had one plug that wasn't gapped properly, and that caused a constant misfire in the cylinder it was in.

[=C=]

Originally Posted by limitdown

If this issue is still showing up in cylinder 1, even with new plugs, coils and injector, then it's possible you have problems with one of the fuel pumps.

You'll need to do a WOT pull in 3rd gear with the pedal to the metal 100% of the time to red line, and log the low pressure fuel psi, and also the high rail pressure. In your log, you let off on the pedal after 3k rpm. Your LPFP shouldn't dip below 60psi and HPFP rail pressure shouldn't go below 2k psi.

It's also possible that one or both pre-cat O2 sensors are dying. Sometimes these don't give codes until they're actually dead. I've changed both upstream sensors 2 times already.

Also check that your plugs are gapped correctly. If you have single-pronged plugs like 5992/95770's, they must be gapped very precisely to 0.55mm/0.022inch . I had one plug that wasn't gapped properly, and that caused a constant misfire in the cylinder it was in.

Thanks, the problem is that I cannot sustain a possible WOT, because after 3.5~4k RPM the engine starts to shake and I feel if I push it any further I'm doing harm to it (that sort of feeling).

If it's running too lean or too rich because of a bad O2 sensor on the way out I don't want to damage the engine in the process. Will check the O2 sensors pre-cat. I wonder if the BMW shop damaged the O2 sensors while replacing both Front/Rear turbo's.


The Bosch spark plugs come pre-gapped, however I may need to check the gap.

Will check the LPFP and HPFP psi, however see my worry above at 4k RPM.

[jwebb335xi]

Originally Posted by =C=

Spark plugs and coils have already been replaced with new parts which cost me a lot already and it hasn't fixed the issue.

I don't like the exercise of guess work to replace parts will-nilly that are functioning OK just because I think maybe it's this or maybe it's that.

Sorry for not being clearer. Regarding plugs and cools, you can remove, inspect, gap, and re-install but in another cylinder. That will allow you to see if the problem moves. Logging to see if fuel is properly delivered will also help determine if the problem is related to fuel pump or pressure sensor, etc...

[=C=]

Cobb support also advised the log showed the afr is oscillating very wildly between lean and rich.

Have ordered 2 new Bosch O2 sensors pre cat and will report back once installed.

If im already down there I might as well install the DP.