SQ5 is shaking

Hello everyone,
"I'm having a problem with my Audi SQ5, model year 2013, engine code CGQB. It's shaking. When I start it when it's cold and give it a little gas, it stutters. Then, when I drive, it shakes occasionally. It feels like a misfire. Yesterday, I removed all the injectors, cleaned the injector seats, and installed the new version of the copper rings. The values for injector quantity deviation have improved, but it's still shaking. I've read something in this forum about a fuel rail pressure calibration point." These look fine to me as well.

Is there another way to determine which injector is causing the problem?

Hello,

If available, I would check the idle speed control values and then the timing deviations of the injectors at different pressures.
And things like being able to see through damaged areas in wiring harnesses.

If the problem is reproducible, log the data. This will show you whether the control unit is running correctly, or whether it is being reset due to intermittent power shortages (indicated by a temporal deviation/pause in the log).

Best regards, Rainer.

I took logs of the calibration points before sealing.

Unfortunately, I can't always trigger the stuttering.

Does that mean the values won't change (will freeze) if an injector fails?

"Timing deviations of the injectors at different pressures. Timing deviations of the injectors at different pressures." How can I understand this?

"Things like inspecting wiring harnesses for chafing."
I did that at the same time as I was sealing the injectors.

Hello,

I don't know if the values will freeze in the event of an injector failure.

Quote:

Address 01: Engine Control Module (8K5 907 589) 22:20:38 IDE01387 Injector 1: Rail pressure calibration point 1, 5.00 µs. IDE01388 Injector 1: Rail pressure calibration point 2, 13.15 µs. IDE01389 Injector 1: Rail pressure calibration point 3, 23.00 µs. IDE01390 Injector 2: Rail pressure calibration point 1, 9.45 µs. IDE01391 Injector 2: Rail pressure calibration point 2, 11.00 µs. IDE01392 Injector 2: Rail pressure calibration point 3, 22.05 µs. IDE01393 Injector 3: Rail pressure calibration point 1, 4.95 µs. IDE01394 Injector 3: Rail pressure calibration point 2, 12.90 µs. IDE01395 Injector 3: Rail pressure calibration point 3, 18.65 µs. IDE01396 Injector 4: Rail pressure calibration point 1, 2.00 µs. IDE01397 Injector 4: Rail pressure calibration point 2, 7.40 µs. IDE01398 Injector 4: Rail pressure calibration point 3, 15.90 µs

That's exactly what I meant by "injector timing variations at different pressures." It looks good, and the injectors look okay to me.

Are there any specifications for the idle speed control system for this engine?

What is the fuel injection amount displayed on your car when idling (engine warm, air conditioning and rear window heater off)?
Are there any tuning boxes or chip tuning modules installed? Here, inappropriate sensor signals or simply bugs in the dataset could be the cause.

When you post an engine control unit (ECU) scan, it shows the VAG part number and the software version of your engine control unit. This is helpful for identifying whether a newer software version is available. Reasons for updating the software in the engine control unit can include emissions compliance, but also simple error correction, such as... Jerky movement in certain operating conditions...

Is the fuel supply (diesel filter, hoses) okay? The concern is that an air bubble might form somewhere while the engine is idling, which could then disrupt the rail pressure regulation during startup, or instead of diesel, foam might be injected.

Best regards, Rainer.

Hello,

What are the values for the fuel injection deviation?
I would start by performing a measurement of the return flow volume.

Best regards, Dago.

Quote:

Injection quantity deviation

Please search here for idle speed control. However, the current CR-TDIs, like the one in my T6, seem not to display this parameter anymore; I haven't found anything. However, the CFFB (Child Seat Fixing Bracket) is installed in my wife's A3.
In general, the values displayed represent the differences in fuel injection volume for each cylinder, which are used to compensate for uneven running and maintain a constant rotational speed of the crankshaft.
The LLR (Longitudinal Barkhausen Noise) is an indicator of problems with the fuel injectors (which seem to be fine based on your values) or mechanical issues within the specific cylinder.

Therefore, it's best to always use a full system scan to know which engine and control units are involved.

Best regards, Rainer.