Posted by Peter Florance on January 14, 2001 at 11:53:53:
In Reply to: cold start gremlins/1981 528i the history posted by w.ollison on January 14, 2001 at 09:59:07:
The fact that the car starts warm but not cold, leads me to think the cold start valve is not proving fuel for some reason. Some trouble shooting is in order.
Remove the rubber boot from the cold start valve and verify it's getting juice. The thermo time switch provides the ground for it and the combo relay (feeding through the ecu) provides the +12V
A small test light may fit in the rear of the connector shell to provide measurement. Sometimes I'll wrap electrical tape or heatshrink tubing around a most of a nail (to keep from shorting the probe of the light) for the ground side of the light so it will fit in the rear of the shell.
Then you can start it cold and see if the light lights. If it does, and you've already replaced the valve, then you must be missing either fuel pressure or spark. Careful making electrical check around fuel; always have fire extinquisher handy.
If it doesn't light, if you can, determine whether it's the hot or ground missing.
They are some harness grounds that are part of this function. I'm not at home now, so I can't check. But a visual inspection of the intake manifold area should reveal 2 or 3. There's one near the firewall that is part of the FI harness that may be important.