Unstable idle

[Apuffe]

Hello, I need your help. When starting from cold, my Mercedes W124 E420 1994 starts with an unstable idle, as can be seen in video n1.

After 45 seconds, as the car warms up, the idle is no longer unstable, as you can see in video #2.

Also when starting the car in first gear, after a traffic light, sometimes the car shakes a little. Has anyone had a similar symptom? What could it be?

Will it help to scan the car with that original Light system? OBD1?

“””The distributor caps and fuel pumps were changed, the MAF sensor was cleaned and the ecological wiring was completely revised.”””


Thanks!
Allan

 

[nocfn]

Hello and welcome. Search for this issue and you will find all of us have been there. It is more than Caps, it is the insulator behind the rotor bracket that most likely has an oily substance on the back of it. Accordingly, the cam seal is most likely in need of replacement as it is suspected to be OE, hard and allowing too much oily vapor to cover the insulator. As such moisture shorts out the system irregularly until it has all burned off. This is general, not specific but that is the well documented issue. It is caps, it is rotors it is insulators it is improper aka inadequate drainage of the caps. Condensation builds on short trips (think of a cold bear in the hot sun...it sweats) and the long hot temps of running will sooner or later burn it off until the next drive. Replace the cam seals, add new insulators if sick mess on the back of them, add some more slots to the caps and be sure coils and wires are in good order.