Starting problems


Asked by Jun 04, 2016 at 07:45 PM about the 1989 BMW 5 Series 535i

Question type: General

I have a 1990 530 I BMW that Battery is being
drained down and it won't start unless I prime it
through the air box and I was told it was a thermo
switch and where can I find the thermal switch
and how does it affect the initial startup

2 Answers


Battery draining is from a parasitic draw, you will need to do some diagnostic work to figure out what circuit. How old is the battery? BMW's need a fully charged battery to operate. But you said you have to prime it, that to me say fuel system. Do you hear the fuel pump prime when you turn the key? If not, then it could be a faulty fuel pump. Check the fuses too. See if you can borrow a fuel pressure gauges to check the fuel pressure if you want.

Best Answer Mark helpful

Yes as fuel pressure at the fuel rail like I said once it starts and runs normal then I shall take you off I have to prime it again someone said about a a thermal switch but what has that to do with initial startup please I need your helpn and I put a new battery in it and it's raining that one too

Your Answer

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