E34 525 starting problem.

[yonghw]

Hello all Sifu,my e34 52 , 12valves needs to be cranked twice( or longer than require) when the engine is cold. My mechanic changed the fuel regulator but the problem is still there. Please help......newbie...

 

[jarance]

Do you have the same problem when the engine is hot?

Could be the fuel pump non return valve passing. If the valve is passing, then either the fuel is return back to the petrol tank and cause the air to trap in the fuel manifold. Try to on the ignition for a few second to let the fuel pump to charge the the fuel manifold and then crank it. if it start on first crank, it could the problem.

Also , have you ever change your fuel pump and fuel filter recently?

 

[piquet]

had a almost similar problem with my car.Couldn't start at all ,turned out to be the flywheel/crank sensor.but maybe yours is related to fuel starvation like they say

 

[yonghw]

there is no problem when the engine is hot...