Golf BKC Idle Speed Control at Maximum

"I'm having a problem with this Golf where the engine isn't running on all cylinders; it's worst right after a cold start."

Address 01: Engine Control Module (03G 906 016 Q)

15:51:23 Block 013: Idle speed control (fuel injection deviation).
-2.75 mg/H, quantity deviation. Cylinder 1.
2.99 mg/H. Quantity variation. Cylinder 2.
-2.47 mg/H, quantity deviation. Cylinder 3.
0.07 mg/H. Quantity variation. Cylinder 4.

"These are the values with a cold engine; with a warm engine, I have something different on the 2nd [reading/measurement]." Zyl only +2.56mg/H.

The previous owner already had some work done on the car.
Turbocharger and intercooler replaced.
Dual-mass flywheel + clutch.
PD elements sealed.
PD cable line renewed.
Twin-screw pump.

First, I measured the compression, which was 36 bar in all cylinders. Then, I bent the pins of the piezo injectors to improve contact (at that point, I didn't know that the fuel line had already been replaced). This didn't work.

Then I swapped the PD elements with new seals, but the problem persists on the 2nd cylinder. The values in MWB 23 are very good, with only a range of -10 to -20.

I couldn't detect any wear on the camshaft or valve lifters. In my opinion, the valve seats for the PD elements are also okay. I haven't had any problems with copper sealing washers before.

The only thing I've noticed is that all the PD camshafts have a point of contact, which suggests that the previous user didn't adjust the collision margin correctly. I can't think of any other explanation. But at that point, the elements should have been dead.

Hello,

The pressure marks on the PD lobes are likely caused by a completely incorrect setting, followed by an attempt to start the engine.
How pronounced are the pressure points, and can these be assessed using measurement techniques?
A half-turn when adjusting the PD elements already makes a significant difference...

I would smooth out the pressure marks as a "makeshift repair."
After that, adjust the setting on the PD element with the smallest amount of power required.
Adjust all other PD parameters in the settings (which affects the amount of boost) and then reduce them until the values for the idle speed control are reasonably close.
So, revert the settings back to between 180° and 360° (for all other readers: there is a technical article on adjusting the PD elements).


Best regards, Rainer.

Thank you, Rainer, for the suggestion. I'll give it a try. I usually turn the knob back 270 degrees, as was the standard practice in the past.

It's difficult for me to say whether the pressure point on the second cylinder is larger than on the others. I've attached another picture of the first cylinder.

Quote:

I usually turn it back 270°, as was the standard practice in the past.

It comes at a cost. Just kidding, it's almost irrelevant in terms of performance.

Okay, I've now replaced the camshaft and lifters, on the 2nd [of something - e.g., day, week, month]. "The cylinder was stuck, but now that the EV (electric valve) is working again, the idle speed control is functioning correctly."
Now I just need to find the error that's causing the low-end torque issue. /viewtopic.php?t=30622, third post.

Thank you for the feedback .