<E30> Thermal time switch problem?

[Norman Boehl <nboehl@xxxxxxxxxxxxxxxx>]

Hey folks,

I've been experiencing slightly longer cold-start intervals, and so I
decided to checkout the thermal time switch ('85 325e).

After removing the connector from the cold-start valve/injector, and
using a remote starter connected to the diagnostic connector, here's
what I found (cold engine - about 88 degrees in the garage):

1)  The "start" signal at the cold-start valve connector has ~12 volts
    during starting.
2)  The "ground" signal that feeds through the thermal-time switch
    measured about 2 ohms to ground (not 0 ohms as per the Bentley
    manual).
3)  Measuring voltage between the two pins of the cold-start valve
    connector during starting measure 0 volts (this contradicts the
    two above measurements), and not 12 volts as might be expected
    (it appears to look like the ground is opening up at crank time).
4)  When inspecting the wiring to the thermal-time switch, I found a
    small resistor inserted into the power lead to the time-switch
    portion of the sensor .. it was soldered in-line, and electrical
    tape covered it up.

I am under the impression that the dealership made the modification (the

resistor) some time in the distant past.  You could tell that the rubber

boot was simply sliced open with a knife, and globs of solder held the
resistor in place.  This resistor is not shown in the BMW Electrical
Troubleshooting Manual, and was wondering if anyone knew why it was
there (Brett?).

I searched the NHTSA service bulletins, and nothing was listed that
resembled what I found.

Anyway, could it be that the thermal-time switch has bit the dust?  It
looks like the timer portion is disabling the ground circuit (acting as
if the water is hot).  Maybe I should do a dynamic continuity check
on the ground lead through the switch while I crank the engine and see
if the 2 ohms goes to an open circuit.  If so, it should not happen
until a few seconds after the initial crank.  If it happens immediately,

I guess I have my answer.

I have not yet tested if the cold-start valve actually sprays fuel
during cranking, but given the electrical tests, it looks like it won't.

I'd appreciate any assistance regarding the above issues (sorry about
the long-windedness).

Later,
Norm

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