Hello. I’m stumped. Tried a lot and now coming here for some feedback. 93 z28 6 speed. Hasn’t been on the road in awhile but used to be started in the driveway from time to time. One day got in and It doesn’t crank. I also don’t hear the fuel pump priming. Immediately thought the vats system. Then noticed I have no security light at all. Doesn’t light up when the key is turned to accessory or nothing. Just never lights up. I was able to jump the starter at the starter relay and get it to crank. Still no fuel pump. Sprayed a little starter fluid in the throttle body and fired right up. I’m stumped as to what it could be. I did the resistor mod on the ignition under the column but no difference. Swapped the tdr relay. No difference. I’m really stumped at this point. Especially with the lack of the security light. Any help would be appreciated. Again it’s a 93. I’ve seen a lot of write ups and stuff but it all pertains to 94+. Seems like there’s a lot different on the 93.

 

The PASS-Key II (VATS) system is similar 1993-1995. I'm looking at Shoebox’s diagram for 95, should be similar, but may have subtle differences. I'm not in a position where I can check the 93 factory service manual (FSM). I'll check it in the morning. Or you can do a free download of the 93 FSM, courtesy of GaryDoug:

https://www.mediafire.com/?40mfgeoe4ctti

http://shbox.com/1/pass_key.jpg

The SECURITY light gets 12 volts (unswitched) from the “COURTESY” fuse. It gets the ground to turn it on from the theft deterrent module (TDM). Sounds like the TDM may be the problem. The TDM also supplies the ground to the TDR, and sends the “fuel enable” signal to the ECM.

When you spray it with starter fluid, it starts. How long does it continue to run?

Have you checked for codes? If the “fuel enable” signal is not going to the ECM it sets DTC 46.

The fuel pump not priming is an issue. Should run for 2-seconds independent of the SECURITY system, then shut down until the ECM gets the “fuel enable” signal.

 

I have not checked for codes. I’ll try to do that tomorrow. It only runs as long as it has starter fluid. Once it dies it won’t turn back on.

 

If you decide to replace the TDM, read the instructions in the factory manual. There is a very specific procedure required to program the TDM to match your key resistance, the first time you insert the key.