long cranking to start '83 528e

[b5m2w8e]

my 528e has to be cranked for an unusually long amount of time in order for it to finally come to life. If it has been run recently it's better, however when it is cold (30 degrees) it gets worse. i have replaced the in-tank fuel pump, fuel filter, and have checked around for any leaks, but not very seriously. I'm thinking that the lines are bad or I have a vacuum leak somewhere. Any suggestions or tips would be greatly appreciated!

[jimoreno]

If is only when is cold try checking the thermotime switch. Also it could be fuel pressure loss after the engine is off. There is a check valve in the system that is known to go bad. You'll need a pressure gauge and the Bentley manual for the test procedure.

Good Luck!

[b5m2w8e]

Actually it has to be cranked unusually long when it is warm too. Only when it has been run recently does it start right up. any idea where the check valve is located? Thanks for the input!

[jimoreno]

Since I don't know the manufacture date of your car, I assumed a June 1983 date. This diagram shows it in the fuel supply line just before the rail:

http://www.bmwmobiletradition-online.com/bmw/showparts.do?model=4073&mospid=47228&btnr=13_1076&hg=13&fg=15

See if your car has it installed.

Regards,