UPDATE: Got it running!!! See threads below what caused the ignition problems.

Hey All,

Long story short but over the last few months after buying this 92 convertible 6 speed with running motor but bad rod knock, I pulled the motor, repaired/rebuilt the LT1 and reinstalled. I have since been trying to figure out why it won't fire. After weeks of research I feel like I'm going backwards. Any help or shop recommendations in metro ATL to help diagnose would be greatly appreciated.Background Electrical:

Prior to pulling engine, I was testing electronic components and only funky thing I experienced was when I turned on the windshield wipers, nothing moved and then I heard a loud pop. The wiper motor is frozen. Didn’t think much about it and figured I'd deal with it after the motor went back in since the wiper motor was removed for engine pull/install.

I then pulled and repaired the short block. Reassembled long block and reinstalled into the car. On install, the steam tube on the heads snagged the wiring harness and damaged insulation on one of the wires. I got some electrical tape an repaired. other wires Looked fine. I also put new connectors on oil pressure sending unit and O2 sensors. Re-loomed a lot of the wiring in engine compartment.

I cleaned the fuel injectors individually and used 9V battery to open them. In the process I found one injector was dead. I replaced and installed the injectors and fuel rail.

No Start Diagnosis History:

When I first attempted to start it didn’t kick at all. I didn’t hear the fuel pump so the first thing I did was check the fuel pressure and it was fine. Also can be verified by the smell of fuel in the oil after multiple cranking attempts.

I broke out my timing light to check if any spark was making it to the plugs. I tried a few leads but no spark. I then attached the timing light to the coil wire and got about 5-8 lights and then nothing. I had the old opti and it wasn’t a big deal to pull the water pump (I hadn’t added any coolant) and swap it out. No change in condition. I then swapped out the battery (it was weak and checked bad at parts store), replaced the coil, the ignition control module, reinstalled the new opti and no change other than cranking faster. I checked all the fuses on the side of the dashboard passenger side and all looked well.

I then jumped A/B on the ALDL port and got into diagnostic mode and it flashed 12 correctly however NO CODES at all.

I verified the coil ground was good and power is getting to the coil. I ran continuity tests on the opti harness and it appeared to be fine.

Today, I pulled and checked all the fused in the secondary fuse panel under the glove box. I found the door lock 15amp fuse was blown so I replaced it. I then cranked the motor for just over 15 seconds to see if a code would be thrown. Oddly, the info center shows “sys” momentarily after turning the key on. Additionally I can NO LONGER get the car into diagnostic mode by jumping A/B. Weird?

I am at my wits end.

 

Hmmm. If you are getting fuel in the cylinders then the ECM and CCM should be talking ok (I believe that if the handshakes fail the injectors are disabled via ECM).

Do you have a FSM? I would think tracing And testing the signal wires from the OPTI would be where I might look....

you could also simply have a bad engine ground after reinstalling. I would check/verify all grounds/main ground on block and make sure clean and tight and that the ground braids are not damaged. Also make sure simple things like wires going to the correct plugs...

that sucks I am sure you are pumped to get this thing back on the road! You’ll get it!

 

It took a few weeks but the mystery is solved. The ignition no-spark issue was caused by the black coil connector down to a few strands of wire. It past the diagnostic test and was hidden by the beautiful new tape and loom I put over the connector while motor was out...that was a PITA to isolate.

Secondly, the timing issue causing a no start condition was caused by damaged splines on the opti drive shaft. Specifically, it looks like the opti was forced on in the past and could be installed misaligned a few teeth as I did. I reinstalled the opti correctly and the rebuilt motor immediately FIRED UP and ran smoothly!

 

Awesome! Glad you got it sorted, hopefully you can start to enjoy it now !