I'm more confident now that the opti is installed correctly (after the 3rd time). I thought about the cat yesterday and dropped it to find nothing inside... (not plugged, nothing there). I also took voltage and resistance readings on the MAF, MAP & IAT sensors and found them to be in normal range. I haven't checked the O2 sensors yet and it's raining now so I'll just have to wait for a break to pull them out see how they look.

 

have the coil tested as well as the ignition module. need a scanner to pull codes and one that works with the 94

 

The coil is new, but the ignition module isn't so I'll add that to my list of things to test. Thanks!

 

just an afterthought,,, did you put threadlock on the screws that hold the rotor on? good idea to do that.

 

OK, it's been awhile since I've posted because I can't seem to make any progress on diagnosing the real problem. I managed to find someone with a scanner that was actually capable of pulling codes from a 1994 Z28. I purchased a code reader that didn't work only to find that the 94 is a bastard year for this car with an ODB1 connecter and ODBII system that can only be read with a scan tool. We weren't able to pull any engine codes, but did pull out a couple of automatic transmission codes. Unfortunately it's a manual transmission car. No help there. So the issues are 1. limited throttle response. 2. Exhaust manifolds start to glow after only a few minutes running. Injectors are staying open too long for some reason. So this is where i started, well almost. Initially the car ran great until it reached normal operating temperature then started running rough and would not start again until it cooled down. Replaced optispark, plugs, plug wires, coolant and temperature sensors as well as TPS, Coil and various other sensors I couldn't get a good reading on. Now instead of waiting until the car gets to normal operating temp it will only idle until the exhaust gets so hot I have to shut it down.
Any diagnosticians out there that may be able to point me in a specific direction?

 

make sure you arent getting fuel in the oil. sounds like it running very rich. have you tested the fuel pressure?

 

Glowing exhaust manifolds can mean either the engine is running lean, not rich (fuel has a cooling effect), or the timing is way retarded and the late combustion flame is getting blown out the exhaust instead of down the cylinder. You're absolutely, absolutely sure the opti is on right?

 

Not sure how I would check for fuel in the oil. Someone else suggested it's dumping too much fuel which I thought would account for the glowing exhaust? I've tested the fuel pressure several times, the last time just a few minutes ago and it's down to about 39psi with the key on, was about 40-42 a couple of days ago. I also pulled a vacuum on the pressure regulator and the fuel pressure dropped so it looks like a weak fuel pump at the very least.

 

I had the opti apart with #1 at TDC to make absolutely sure of the installation. My second attempt actually, it wouldn't even start on the first try (180 out). I even changed out all the plugs and wires checking and double checking with another set of eyes...
As for the glowing manifolds, I'm at a complete loss. The scan tool did indicate the injectors were staying open for an extended duration which is what led me to believe it's running rich. The only suggestion I've heard for this is a possible exhaust manifold gasket leak, bad O2 sensor maybe? again I'm just not sure...

 

If you're dumping raw fuel into the exhaust, the cat converter would glow red because it's burning the gas (that's part of the cat's job). Is it turning red?
On the flip side, a lean running engine runs hot (remember, fuel has a cooling effect), and lean can make the exhaust manifolds glow. 2 different symptoms from 2 different issues.