Waving idle speed in BMW - what is the cause and how to fix it?
When the suction is turned off, the engine at idle runs irregularly - it ripples. I do not know how to deal with this problem. The valves were set, I replaced the lambda probe, spark plugs and ignition cables. I cleaned the ignition cluster dome, stepper motor and blew the air flow meter with air.
BMW driver question
When the suction is turned off, the engine at idle runs erratically - wavers. I do not know how to deal with this problem. The valves have been adjusted, I replaced the lambda probe, spark plugs and ignition cables. I have cleaned the dome of the ignition apparatus, stepper motor and purged the air flow meter with air. Please advise.
The problem was with a 1989 BMW 320i E30, but it may also occur in other models.
Response from BM Cars service
A very common fault that causes idle speed ripples in gasoline engines is a leaking engine air supply system. In BMW engines in both the E30 and its successor E36 and subsequent models, the air ducts were made of plastic. Particularly vulnerable to breakage and damage was the piece connecting behind the flow meter with its characteristic "accordion".
After many years of operation in harsh temperature conditions, the elasticity of this element rapidly decreased, resulting in the formation of micro-cracks and gaps supplying the so-called "left air. A very common cause of damage to this element is also alterations during the installation of LPG supply.
We recommend doing a thorough diagnosis of the power system and other engine components.
Other BMW tips related to the topic at hand
- Exhaust smell and smoky engine in BMW - what is the cause and how to fix it?
- Fading engine in BMW with automatic transmission - how to fix it?
- Jerking and white smoke on cold engine in BMW - what is the cause and how to fix it?
Read more tips and ask your own question
[button type="theme" link="https://bmcars.net/porady-techniczne-bmw/" rounded="10"]Free Technical Tips[/button]
