I have a 94 Z28 6 spd, basically stock, I just installed a new reman. optispark, plugged in the scanner actron for obd1 and the ignition timing reads 20deg while the engine is running at idle 800 rpm, is this normal or is the optispark spline a tooth off when I put it on? car bogs down when I accelerate especially when hot, and overheats also. Any help would be appreciated greatly, thanks Kris

 

At 800rpm idle, the stock programming timing advance on an LT1 is in the range of 18-22 degrees, so what you are seeing is normal. When you hook up a scanner, it reads what advance the PCM is calling for. It has no way of knowing what the actual timing is, nor would what the scanner shows change if the Opti was indexed incorrectly to the splined driveshaft.

 

Thanks for the info. very helpfull. So I took off the air filter element and ran it to see if the filter was constricting and it still did the same thing..overheated and bogs down when I press on the gas, no codes at all. I think maybe its something to do with the fuel, ill change the fuel filter and check the fuel pump. I hope I don't find out that the new reman opti is bad or that I put it on wrong, which is almost impossible with the index keyway, and it seemed to go on completely flush.. What was the point in buying the scanner, thought i was immediately going to be able to pin point the problem..frustrating

 

I'd estimate that as many as 15-20% of the unvented Opti installs end up with the splines indexed incorrectly. The problem shows up frequently here, and has for years. People will swear they did it right.... but you'd be surprised how often they didn't.

 

A mute point, whether or not, the opti was installed incorrectly. To re-enforce (as if he needed re-enforcement) what Fred noted, the PCM wouldn't know the diff. It is programmed by design, to not address/recognize issues with mechanical hard parts. It is EXPECTED, the mechanical parts are installed according to manual. Also of note, and no different, wouldn't know (or care) whether or not a cam was installed correctly..... according to manual and/or engineeringspecs.

 

Thats interesting and makes sense, im just going to replace the opti with another reman one. I think it may have been bad, even though it was remanufactured and supposedly back to new condition but you never know. With the indexed spline it seems like you can't really miss when putting it on. This will be the 3rd try now, thanks for the info about the scanner not reading it being on wrong.

 

I'll say this one more time... and then I'll leave you on your own. It is entirely possible to assemble the splined shaft incorrectly. It happens all the time. It is not fool-proof. It requires care in assembly, and verification that it is done correctly. But if you feel is is not possible, good luck with your install