ok i know ive posted this a long time ago but here goes another try
"the shortened version" what can cause this ina 99 cav Z24 4spd auto
when i turn the key to "run" the check engine light will flicker for a half a second then go back out wont stay on like its supposed to i have no fuel no spark but there is power and ground at the pcm, ign module, and fuel pump relay the relay wont click even after changing it if i jump the wires the pump will run alternator tested good the the following are new ( ign module, ignition sitch and passlock tumbler, cam sensor, crank sensor, gauge cluster, and pcm) also did relearn after adding these i know theres no fuel because the relay and pump dont kick on unles i jusp the pump and i know theres no spark because it wont run with starting fluid alsom plugs wires and coil packs are only about 6 months old and bettery is new and all the major power and ground wires seem to be in good health any ideas guys please help thanks DAVE

 

possibly ignition switch, not lock, but the switch itself. or blown fuse or fusible link.

 

Is the engine turning over when you turn the key?

 

Sorry, didnt pay attention to title. There are some TSB's on the ignition 04002,
<TABLE class=tableTSB id=ctl00_CPH1_Table1 border=0><TBODY><TR><TD class=number>TSB Number: 02232004</TD><TD class=nHTSA>NHTSA Number: 10013000</TD><TD class=date>TSB Date: February 23, 2004</TD><TD class=add>Date Added to File: April 5, 2005</TD></TR><TR><TD colSpan=4>Failing Component:
Electrical System:Ignition</TD></TR><TR><TD colSpan=4>Summary:
If the engine fails to start and the driver holds the key in the start position for an extended period, high current flows through the ignition switch and sometimes produces enough heat to melt internal switch parts. Discuss It in Forum
</TD></TR><TR><TD vAlign=top rowSpan=3>2</TD><TD class=number>TSB Number: 04122004</TD><TD class=nHTSA>NHTSA Number: 10009214</TD><TD class=date>TSB Date: April 12, 2004</TD><TD class=add>Date Added to File: September 17, 2004</TD></TR><TR><TD colSpan=4>Failing Component:
Electrical System:Ignition</TD></TR><TR><TD colSpan=4>Summary:
Ignition circuit thermal events, three phase safety recall 04002. GM voicemail express. Discuss It in Forum
</TD></TR><TR><TD vAlign=top rowSpan=3>3</TD><TD class=number>TSB Number: 04002</TD><TD class=nHTSA>NHTSA Number: 10007858</TD><TD class=date>TSB Date: May 12, 2004</TD><TD class=add>Date Added to File: July 13, 2004</TD></TR><TR><TD colSpan=4>Failing Component:
Electrical System:Ignition</TD></TR><TR><TD colSpan=4>Summary:
Product safety recall ignition circuit thermal events.</TD></TR></TBODY></TABLE>

 

i have replaced both key tumbler and ignition switch all the fuses and relays are good under hood and box inside on driverside dash panel are there any sort of relays in any other places that have to deal with this the only fuesable link i found was between thestarter and alternaterits a wiretype fuesable link (14gauge grey)

 

sorry almost forgot yes engine turns over just wont fire due to what ever is causing this its cutting off both fuel and spark