VW Audi TDI engine (AFN, 1z, AHU etc) Bosch VE EDC Stuttering/Jerking problem. (speed correction)

Lasali

New member
Joined
Nov 5, 2022
Location
Hungary
TDI
Vw passat b5 afn
Hello!
There is a common problem with cars equipped with bosch ve edc. Many people suffer from it...
The problem occurs when the car is tuned.
At constant speed, stuttering the engine between about 1500-1900 rpm. (for example, in 4th gear around 70km/h or in 5th gear around 90km/h)
The symptom intensifies when the air temperature drops.
The bosch ve injection pump is good, HDK cleaned or no metal shards in it, refurbished, higher pre injection etc.. the problem is constant..
More ideas came up in the forums. for example, to eliminate the speed signal.
For example, they experienced a VW b5 passat afn:
If I disconnect the speed sensor from the transmission: the stuttering will be of lower frequency but continuous in all operating, the car is driverless.
When i addition disconnect the abs module, the stutteting break off in constant vehicle speed, the car drives smoothly, the engine does not stutter. BUT! If reduce the throttle positon to zero, for example during a gear change, then we give it a little throttle positon again the stuttering appears very strongly! The same thing happens when we try to drive on a slope with a low throttle pedal position!

I also tried to disconnect the "Motronic engine control module" white/blue cable from the instrumental cluster, the result is the same as when i disconnet the speed sensor in transmission and disconnect abs module.

Why doesn't it stuttering the constant speed of the car if there is no speed signal?

What is the solution to prevent the car from stuttering due to speed correction?

Thank you in advance for your help!
 

krook

Veteran Member
Joined
Jan 13, 2021
Location
Hungary
TDI
A4 B5 AWX, A4 B5 AFN
calibrate your pump voltage map. i have 3 tuned afns and none of them have this problem.
 
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