Long crank unless I hit the gas pedal to open throttle bodies

Specific conversations and info for the BMW E28 M5 and M535i.
Post Reply
S62ninja
Posts: 12
Joined: Aug 19, 2020 8:54 PM
Location: Los Angeles, CA

Long crank unless I hit the gas pedal to open throttle bodies

Post by S62ninja »

Having some issues with long cranking. Car usually starts up normally but sometimes it will crank until I press the gas pedal and it starts. Is there some sort of idle control valve that needs to be cleaned out for these cars? I did spray carb cleaner around the intake and injectors the other day while idling and didn't find any obvious vacuum leaks.
Preyupy
Posts: 239
Joined: Jun 21, 2012 12:48 AM
Location: Issaquah WA

Re: Long crank unless I hit the gas pedal to open throttle bodies

Post by Preyupy »

There is a ICV under the intake plenum that might be sticking but usually that causes a problem with idle speed not starting. I suspect you might have a problem with the throttle position switch or even a ECU issue. Does it do this on a warm restart as well as a cold start? How much do you have to open the throttle to get it to start? The throttle position switch should only trigger when the throttle is completely closed (or full throttle).

When it does this check for spark, also check for injector firing (you can get a test light you can plug into one of the injector electrical connectors to see if they are firing) You could also have a problem with residual fuel pressure or even the Air Flow Meter and fuel pump relay. The list of possible causes is quite long.
Post Reply