Shaking While Rolling: Causes & Solutions

Hello everyone!

I've noticed an effect for quite some time now, but the cause of it remains unknown to me.
When I allow the vehicle to coast, meaning I take my foot off the accelerator while in gear during driving, I experience shaking and rattling in the front of the car. This effect is not present when I keep my foot on the accelerator and the vehicle is in gear, i.e., in "drive" mode.

Therefore, I can rule out an imbalance in the tire or any other defect in the suspension. This means there must be a connection between the power transmission between the engine and the gearbox and this shaking.
By the way, the engine runs relatively smoothly at idle when the vehicle is stationary (as much as one can say that for a TDI), meaning there are no comparable vibrations to be felt.

Does the EDC modify the idle control in any way when it receives a speed signal, or what could be responsible for this annoying effect? Does anyone have any ideas? Are there any people with VEP-TDIs who might be experiencing the same problem?

Regards,
Alex.

/viewtopic.php?t=658&highlight=rough+idle+rollers

Good luck!

Thank you for the link, Rainer!

Unfortunately, I've already tried that without success. My current pump setting is around 4-4.2 mg/H in the warm, idle state. You mentioned that the stuttering you experienced occurred at very low speeds while rolling. Did you also test it at higher speeds?

It actually happens to me every time, whether I'm driving at 30, 50, 70, 100, 120, or 140 km/h; I always notice this shaking.
I had also adjusted my pump to 5 mg/H using VAG-COM, but I didn't notice any improvement regarding my problem, other than a reduction in power.

What influence does the speed signal have on the EDC (Electronic Diesel Control) in this context? What changes occur compared to the idling state?

Regards,
Alex.

Hi Alex,

No, in my case, it was only detectable at speeds below 30 km/h.

Quote:

Does the EDC modify the idle speed control in any way when it receives a speed signal...?

Okay. In my case, the problem was resolved by disconnecting the speed limiter. Of course, that's not a real solution, so I mechanically modified the association between the regulator and the quantity setting device of the ESP, as Ulf described in his article/link.

Best regards, Rainer.