Really weird problem starting

[captainmorgan]

I have been trying to figure out my cold start system on my 86 535is for the past year without having to buy a bunch of parts only to find out that they did not fix the problem. I am in college and my budget wont support that. But I replaced my csv with a used one that supposedly worked and also my thermo time switch with one that I knew worked. So last night I go to start the car and boom it starts up immediatly in 58 degree weather. Then this morning in 70 degree weather my car takes 10 secs of cranking to fire up...

I don't know what is up. Can someone please help me?

Possible other parts it could be?
Idle control valve
Coolant Temperature switch
Electronics ie bad wiring
fpr



I have also tried switching the ecu and running through the idle faq on the post below
Also i have run through the bently multiple times I am just wondering why it works some times but at other times not.


[Edit by captainmorgan on [TIME]1129565694[/TIME]]

[rexmo]

Try turning the key to On for a few seconds to let the fuel pump pressurize the system before cranking, see if that makes a difference.

I don't think it takes much time for the smoke to build up in the electronics.

[captainmorgan]

Interesting... I hadn't even thought of that before. I will try that in the morning when I seem to have the problem.

[spinedocab]

I may be wrong, but I don't think the fuel pumps actually start up until the starter motor is engaged. I don't think that just ignition on does it.

This intermittent cranking sounds like random loss of fuel pressure when parked. Maybe the check valve holds sometimes, and not others??

Andrew.

[captainmorgan]

At 52 degree weather this morning the waiting did not help. How would I go about checking the check valve? Sorry kinda trying to figure everything still. Should I replace the fuel pressure regulator?

[e6figueroa]

i rebuilt my wifes 528e, try to check the spark plugs first, distributer, may the fuel filter is dirty, put some fuel system cleaner in it. wires and coil might be another option. these are cheap ways first then start digging into the fuel system. good luck man.