Yesterday I went to start the car to go to work and it would just keep turning over and not fire up. I looked at my scanmaster and it was showing codes 16, 41 and 42 which are optispark low resolution pulse not found, ignition control circuit open and ignition control circuit short or grounded. I popped the hood, wiggled the plug connections, coil connections and opti connections. Everything was tight so I went to start it again and it fired right up so I drove the 40 mile round trip to work and back. Now this morning, it won't start again.

Opti is stock vented unit with 15K miles, coil is MSD with less than 5K miles, ICM is stock with less than 5K miles, wires are MSD with 15K miles.

 

disconnect all the connectors between the opti and the PCM and check for corrosion or other problems. Spray them with WD40 and reseat them. Do the same for the ICM connections.

 

Did the same codes reappear?

 

I cleared the codes out of the pcm and tried starting it. It still wouldn't start and no codes appeared. I'll work on those connections tonight.

 

I followed your advice, speedy, and the connectors looked fine. They were clean and I didn't notice any corrosion. I cleaned them with electrical cleaner anyway and followed it up with WD40. I went to start it and it fired right up. I drove it around for about 30 minutes with no problems.

That was last night. This evening I went to start it and it wouldn't start again. Kept turning over but wouldn't fire and there are no codes.

 

If there really are no codes, I suggest you get back to basics. First check at least 3 plugs on each bank for spark. While you have the plugs out for testing, you can visually check them for indications of what the engine may have been doing.

If they show proper spark, then its time to check the fuel system. The simplest is to simply squirt fuel into the intake while someone cranks it over. If it starts up and shuts right back off, then look at the fuel pressure as this would indicate you have a fuel problem of some sort.

 

Well, I checked for spark on 2 and 4 and didn't get anything so I checked for spark at the coil and didn't get anything there either.

I looked at shoebox's site under 'How To' and followed the instructions on making sure opti signals are getting to the coil here: http://shbox.com/1/how_tos.html

The wires leading to the ICM were showing the correct voltage so I hooked up my old ICM which works and it still wouldn't start so I plugged the original back in. I hooked my stock coil up and this time it did start and it ran. I hooked my MSD back up and again it started and ran.

Essentially I'm still in square one. I haven't replaced anything or found out why it wasn't starting before so I still can't trust it enough to drive.

 

It could be that it was a loose connection somewhere. When you disconnected and reconnected, it could have solved the problem.

 

I had another episode of it not starting today and since it started last time after I messed with the coil, that's where I started my troubleshooting this time.

I unplugged both the harness connector and the plug wire from the coil, then plugged them back in and it started and ran just fine all day. Now I just need to see which wire is causing the problem.

Is that harness wire what the PCM uses to tell the coil to fire?

 

The signal to fire the coil is sent by the PCM, via the white wire from pin B5, to the ICM pin B. The ICM fires the coil via the gray connector.

 

I had another no start episode so I plugged the stock coil in and it started and ran fine. I plugged my MSD in and it wouldn't start. That was the pattern I experienced about 5 times so I went to O'Reilly's and got the same MSD coil (part # 8226) and everything's been working great for 3 days now.

My MSD coil was the culprit. I'm a little irritated it went out after about 6 months though.

 

Never heard a good word on this board about MSD items. But have heard quite a few bad ones.