Rough Idle & Engine Shaking under load like AC

[bigBADbenny]

From the LV, we can see your fuel corrections are just exceeding -5% in idle range.
That’s around where you’d take action and look for an inlet tract through to crankcase leak.

Your IAM has dropped to .7 from 1.00, indicating it was knocking at some point, probably off load, cruise or idle.

I’ll peep the log later

[bigBADbenny]

Also, can you make an RR log of off boost normal driving?
Cold start to warmed up, cruise, start stop etc. 15 minutes or so.

[ilib11]

Thank you, bigBADbenny!
There was a lot of rain here yesterday so I did not capture a normal driving. Will try to do today's afternoon. Are the parameters I was capturing enough or do I need to add any extra?

RE inlet tract through to crankcase leak - just to make sure I understand it correctly - are you talking about a leak at a specific point where inlet (a collection of 4 plastic pipes) connects to the engine cylinder heads? Is that a common place to leak?
I looked in general to see if there are any worn rubber pipes etc. or other sources of air leak but did not find any obvious ones.

I suspect that means taking off the inlet and replacing gaskets 14035A 14035AA421 - right? or 14035B 14035AA492?


The list of parameters I captured:

A/F Correction #1 (%)
A/F Learning #1 (%)
A/F Sensor #1 (Lambda)
Battery Voltage (V)
Coolant Temperature (C)
Engine Idle Speed User Adjustment (A/C off) (rpm)
Engine Idle Speed User Adjustment (A/C on) (rpm)
Engine Load (Calculated) (g/rev)
Engine Speed (rpm)
Engine Speed/100 (rpm)
Exhaust OCV Current Left (mA)
Exhaust OCV Current Right (mA)
Exhaust OCV Duty Left (%)
Exhaust OCV Duty Right (%)
Exhaust VVT Advance Angle Left (degrees)
Exhaust VVT Advance Angle Right (degrees)
Fine Learning Knock Correction (degrees)
Fuel Injector #1 Pulse Width (ms)
Global Timing User Adjustment Value (degrees)
IAM (multiplier)
Ignition Total Timing (degrees)
Injector Duty Cycle (%)
Intake Air Temperature (C)
Intake OCV Current Left (mA)
Intake OCV Current Right (mA)
Intake OCV Duty Left (%)
Intake OCV Duty Right (%)
Intake VVT Advance Angle Left (degrees)
Intake VVT Advance Angle Right (degrees)
Learned Ignition Timing (degrees)
Manifold Absolute Pressure (psi)
Manifold Relative Pressure (Corrected) (psi)
Mass Airflow (g/s)
Mass Airflow Sensor Voltage (V)
Roughness Monitor Cylinder #1 (misfire count)
Roughness Monitor Cylinder #2 (misfire count)
Roughness Monitor Cylinder #3 (misfire count)
Roughness Monitor Cylinder #4 (misfire count)
Throttle Opening Angle (%)
Vehicle Speed (km/h)

[bigBADbenny]

Usually just tuning parameters, they’re listed in the tune faq link in my signature

Things like avcs and misfires are ok to log in the context of tuning parameters, but switch them off once any issues are resolved as less parameters equals greater log resolution.

[bigBADbenny]

As regards inlet tract leaks the deeper ones on and around the top of heads and block can be spotted with a strong torch and inspection mirrors.
Look for oily black fallout around cam sensors and the inlet manifold gaskets.

There’s also an faq on actual inlet pressure testing with smoke or bubbles.

Be sure your maf is properly seated and its oring isn’t cracked or pinched.

Its easy to overlook the simplest things

Eg try pushing on the intake and various hoses whilst idling to see if rpm changes...

[ilib11]

Hi All,
Thank you for your attention to this thread.

I did some checks and got more RomRider logs today - here they are: https://mega.nz/file/ZPgkwAyC#V0CxnjTF9QODtcJTKZSIGoh29jMIfqKy7BWaJZXy0qI

I also took off the engine plastic cover and tried a leak test with a butane gas - Engine was running idle, on parking, AC off and I sprayed a gas from a gas torch
around MAF, inlet, injectors etc. No visual change in idle were noticed during this procedure. May be I need more thorough tests with a carb cleaner.

Thank you and best regards, ilib11

[bigBADbenny]

Taking a peek later

[ilib11]

Thanks a lot, bigBADbenny - I do appreciate your help!
Looking forward to hear what these logs can say.
Thank you and best regards, ilib11

[ilib11]

Hi All,
Checked again oil filler cup - it is fitted tight.
On stationary & idle, when open, there some air pulsations from the oil filler tube, looks like a slight positive pressure.
Having the oil filler cup open does not change the issue - all the rough idle symptoms & shaking under load are the same.
Regards, ilib11

[bigBADbenny]

The log I looked at, the driving log I think...
AVCS is OK so you can switch off all the related parameters, till next service or whenever.
Same for misfires I think, although it did show one misfire on cyl2, hmmm.

A/f learning 1 suggests to me an inlet leak affecting idle range...
Its not going to kill the car but might be contributing to the idle issues.

Personally I'd look for an exhaust or inlet leak, basic non intrusive things.
I can help out if youre in Melbourne

Screen Shot 2020-12-19 at 15.32.15.jpg (209.47 KiB) Viewed 2729 times

[ilib11]

Hi, bigBADbenny, huge thanks for the analysis!

Unfortunately I am in Brisbane, otherwise I would come for sure. Here in this thread was a recommendation for Subievolution service in Bri - I'll try to talk with them regarding leak tests.

What I also did recently ( after the logging files that are attached in posts above):
1) swapped ignition coils between cylinder 1 and 2 - no change in the engine behaviour. Still got a single misfire count in the same cylinder2 in a log after a driving. Tried to catch it or replicate in realtime in romraider graph - no luck. Just one misfire in the log.
2) I used Free SSM and its Idle RPM adjustment and added +150 rpm as an adjustment for both Idle with AC on and AC off. That helped with the issue a bit - shaking become a slight vibration ( but you still can sense it) , rpm does not change such aggressive anymore after AC turns on. But I can see it as workaround, not a solution.

I also thought that in case of an intake leak, we would see less than normal Throttle Opening Angle (%) parameter - as the throttle would be opening less to compensate for a leak. I do not know unfortunately what that value would be on a completely normal engine & idle.

And another theory - I noticed some irregular behaviour of that Throttle Opening Angle (%) parameter - looks like actual opening the throttle is delayed - the Throttle Opening Angle (%) parameter is increasing but RPM keep dropping.
May be the actual butterfly valve movement stuck at small angles so that Throttle Opening Angle (%) parameter has to overshoot to initiate butterfly movement and that takes some time and that time is enough for rpm to drop? Please see the picture attached below. It is a couple AC on/offs followed by a couple times with transmission selector put to R and back to P.
Anyway, will continue with a leak test first.

Tanks again and best regards,
Ilib11

[bigBADbenny]

I would need to get the spark plugs extracted to check that According to the invoice, they installed 22401AA761 which are the right ones...

Missed this!

If all of the issues are post spark plugs install, and easier health checks have come up negative, I'd be tempted to check spark plug torque.

[LibertyTragic]

I would need to get the spark plugs extracted to check that According to the invoice, they installed 22401AA761 which are the right ones...

Missed this!

If all of the issues are post spark plugs install, and easier health checks have come up negative, I'd be tempted to check spark plug torque.

I don’t believe in coincidences, so if my car was acting up post a service, I’d be checking over all the things they touched as a first course of action!

[bigBADbenny]

Absolutely, in the FSM the scope of misfire DTC’s is broad and extends to too rich/lean DTC, in the instance of single cylinder misfires or eg plug tq.

As stiful pointed out, all the basics factor including pushed in loom pins & rounded sockets plus apprentice mishaps.

Try to hold off on the parts cannon and keep checking & testing it.

Did they reinstall the air filter clean & seat the maf properly?

I was reading FAQ’s on this subject and using upper engine cleaner is a must regardless.

[LibertyTragic]

Last time I went to a dealer I had:
- Cross threaded wheel stud
- Broken engine cover clips
- Overfilled oil
- Insufficient bleed in coolant system

Good times!