97rebuiltZ28

I looked around and couldn’t find a similar question. The reason I ask is I’m replacing my optispark and would like to know if the new one is functioning fine without having to put everything back on first. Can you start it with just the optispark on the car? It’s a 1997 btw.

shoebox

Shouldn't be an issue for a quick test.

BTC

I've done it for the same reasons.

97rebuiltZ28

Did it cause any codes or any other problems immediately after putting everything back on?

BTC

My car is a '94, but I don't recall it throwing any codes or causing any problems. It's also been several years since I did it. If it does throw codes, which is always possible depending upon what you do & don't have hooked up when you start it, I believe you can always clear them by disconnecting the battery for a little while.

Just don't let it run very long as you won't have coolant flowing through the block.

Injuneer

Just to clarify.... is the water pump installed? You asked specifically about the radiator, but then mentioned "just the Optispark on the car". You can start the engine without the water pump. As noted above, just don’t let it run too long, to prevent overheating.

Without the water pump, is the coolant temp sensor still connected to the harness? If not could set a code. Is the inlet elbow and MAF sensor in place and connected? Ditto for the IAT and MAF sensors, if not plugged in. Again, engine should start, and no I’ll effects. And if you set a code, easy to clear after the reinstall is complete.

Have you considered turning the key to "run", hooking a volt meter to the Opti signal wires (one at a time), rotating the engine slowly to see if the signal voltage switches back and forth from 0 to 5 volts? That would verify Opti cam position sensor. Or, when you turn the key to "start" you should see the tach needle move up a few hundred RPM. Would not verify correct indexing of the Opti to the cam dowel pin, just that the Opti cam position signal is there.

97rebuiltZ28

Thank you all for your replies. @Fred the water pump wouldn’t be installed yet at the time of the engine start. I’ve honestly never been good with electrical parts so that’s why I haven’t ever tried the volt test. So I’ll see if it runs tonight or tomorrow and update if it does run.

97rebuiltZ28

Update: I just installed the new opti and then put the balancer pulley back on and it fired right up!

shoebox

Good deal!