[zr1mom]

From Marc Haibeck:

Here are some ideas on how to sort through an intermittent no crank
problem. This applies only to '90 - '92 ZR-1's. The wiring was improved in '93.
In the shop, the current on the purple wire to the starter can be
used to analyze the problem. The normal starting current on this
circuit is 10 to 12 amps. If the current is higher, there is a short
in the starter solenoid. This is a common failure mode. Often the
starter current will be normal when the engine is cold and too high
when the engine is hot.
If the no crank occurs on only about one out of a hundred starts,
another strategy might be better. Fabricate a jumper wire, 12" long,
14 gage, with male and female 1/4" spade connectors on each end. Plug
one end into the purple wire to the starter on the clutch switch
connector. Remove the aluminum crash panel from under the steering
column. It's attached with four 10 mm head fasteners. Remove the VATS
interlock relay. It's the relay closest to the left side of the car.
There are three yellow 10 gage wires on the relay socket. Plug the
other end of the jumper wire into one of the yellow 10 gage wires in
the relay socket. Crank the engine. Only one of the yellow wire
connections will work. If the engine does not crank try another one.
With this connection, the clutch switch and the VATS interlock relay
are removed from the circuit. The jumper connects the ignition switch
contacts directly to the purple wire going to the starter solenoid.
If the car doesn't crank in this configuration, the starter is the
prime suspect. The VATS, the interlock relay contacts and the clutch
switch are out of the picture.