87 corvette no start, power is good, all lights work

or the Sentinel ????? What's this ??? SOLENOID on the starter ? Do you know how the starter circuit works ? Do you know what happens when you turn the key to the start position ? Turning the key to start sends a voltage signal to the PCM - engine computer , which will energize the starter relay which sends B+ voltage to the S terminal on the starter solenoid . Checking for a ignition switch voltage to the PCM can be done at the crank fuse 10 amp . located in the underhood fuse box. If B+ voltage is see there ,using a DVOM - digital volt ohm meter , the ignition switch is good . Moving on , find the the starter relay in the under hood fuse box. Pull it out of it's socket an look on the bottom of it , you will see four set's of numbers 30 ,87 & 85,86 . Taking a piece of wire (12 gage ) jump 30 to 87 where the relay plugs into the fuse box. If the battery cables are good an good connections at the battery , The starter if good will crank the engine (spin the engine ) If not ,could have battery cable problem . Need to do voltage drop testing .

Starter Voltage Drop

Is the SECURITY light lit on the instrument cluster ? car an padlock symbol . anti-theft system problem if it is .

Make sure battery has a full charge and battery connections all good. The diagram is for starter motor. Not only check the fuses, use a test light and check voltage on fuse circuits. You have a starter relay, You could, for testing, unplug the relay, use proper jumper wire on load side of relay, the load side is terminal 87 and 30. It should crank the engine. If you try that make sure tranny is in park or neutral and parking brake is set.
Your security system says, starter motor disable. By using the jumper, your bypassing that for testing. I don't know what testing you've done?

Check starter relay for proper power and operation. Underneath drivers dash area

Clean the ground terminal and post them try

first ensure good baytery and connections both at battery and connecting points . check all fuses associated with starting and security ignition etc... check dash lights in run position if on proceed if off look into that first. check to see if the security light comes on for a few seconds and goes off. if it does then proceed to start/ if security light stays on or flases continiously then look into security issue. if when key is in crank over or start position listen to hear if you can hear starter relay/ solinoid on starter try to enguage if not trying to start check neutril safety and or clutch swich is working etc if all this is checking out ok use test light and see if when in start position there is power at solonoid wire( the small wire on starter by itself) if not try jumping power to it bu make sure in park and or neutril position or car may leave you if starts not a funny seen!! good luck!!

If by lights, you mean the dash lights come on, then ignition switch must be getting power. If dash is not working with key on, check the 30 amp fuse link which powers the ignition switch.
If switch is good and starter is good, the start wire from switch goes to, if automatic, to inhibitor relay (the park/neutral function) and then to starter. There is also an inhibitor switch on the shifter or on the transaxle that turns on the inhibitor relay when key is on and shifter in park or neutral. The inhibitor switch is powered by a 10 amp fuse D.
If you have a manual transmission, the start wire from ignition switch goes to the clutch interlock relay and then to the starter. This relay is turned on by the clutch interlock switch on the clutch pedal.
You can check for power on either relay, the inhibitor relay or the clutch interlock relay, with a test light. Pull the relay out, have the key held in start position. Now both relays would have power showing on two terminals where the relay plugs in. If inhibitor relay only has power on one terminal or no power at all, either ignition switch is not sending power or fuse D is out or the inhibitor switch is not working right. If clutch interlock switch does not have power on two terminals either the ignition switch is not sending power or the clutch interlock switch is bad.
If the relay checks are good, check for power on the small wire to starter with key held in start. If you have power there, the starter solenoid must be out.

At the starter ck. the small wire for 12v. when the key is turned to start,if 12v. are there replace starter if not replace ingnition switch

check for proper current from alternator more than13.5 volts that should do it if not check active codes if its not stolen

It is possible the car jumpe time. It coul also be the ignition switch need to be replaced. Good luck

I had a similar problem on my 92 LT1 and it turned out to be the opti-spark was bad not signaling the injectors to pulse, if your bypassing the VAT to turn it over then the injectors should fire as well, on the 92 the crank sensor is built into the opti-spark distributor as well, if it turns out to be the opti-spark spring for the MSD sealed and vacuum vented cap or you'll just be replacing the thing every six months, you can test the opti up were it runs into the coil, I dont remeber the exact proceedor but it is on line,