87 intermittent starting problem

[Ted K.]

You guys have been a great help on several of my older Vettes, maybe you have some info on a frustrating starting problem on a 9000 mile 1987 Coupe. Starts and runs fine most of the time but occasionally turn key and nothing hapens, no click no nothing, usually at the most inopportune time. Took car to shop and it won't act up. Any experience with this problem,or suggestions???
Much simpler with the older Vettes.
Thanks, Ted

[Ernie F.]

[Peter C.]

87 intermittent starting problem: VATS Module

Hi there:

You can take the top of the dash off a 1987 vettw very easily as the dash top is truly just the dash top. Make sure you remove the screws adjacent to the defroster vents (its handy to have a telescoping magnet handy so that the screws don't fall down the defroster vents).

Then you should look for a module about 4 inches by 4 inches with two large gauge yellow wires and various other wires on the passenger side behind the corvette dash cushion. One yellow wire is for the start signal from the ignition switch (what I could call input into the VATs module). The second yellow wire is output from the VATS module and goes to the starter solenoid. If the VATS module works correctly then the first yellow wire will receive 12V from the ignition switch when turned to start and then pass that current onto the second yellow wire connected to the starter solenoid so long as the VATS resistance value is appropriate.

To repair do the following:

1. Take your test light and push it into the connector of one of the yellow wires.

2. When the vette does not start, make sure the yellow wire is getting 12V if not then go to the second yellow wire and do same test.

3. This second test should tell you which is input and which is output.

4. At this point if you want to disable the VATS then you can solder a jumper in between the two yellow wires thereby bypassing the VATS. Although I would not receommend this as a permanent cure. As the VATS system is very effective and I would be looking at repairing the VATS system ASAP.

Best of luck.

Peter Cook