I have a mostly stock (cat delete, egr delete, no air pump, magnaflow exhaust with stock headers) '93 LT1 with a T56 in the car. The bin I'm running at the moment has the stock fuel and ignition tables. It's been sitting for the past year, but I started the engine every week or so. The exhaust smell was very strong, so I started to check whats up.

Both left and right BLMs are at 108, int values are still low. I checked with a wideband and it confirmed the rich condition. In open loop I'm getting 9-10:1 AFR. In closed loop with the computer compensating as much as it could it's around 14.4:1.
The fuel pressure regulator was replaced with an AC delco unit about 2 years, and I the fuel pressure is normal on measuring. If anything it's maybe a bit low at idle ~36psi, but without vacuum it's notmal 44-45psi.
The injectors seem to hold pressure when turned off, so I'm assuming no leak either. Opti was replaced about 2 years ago, and seem to be working fine, also the spark plugs and wires are okay, no visible arcing. The O2 sensors are denso and also relatively new. I checked the throttle body, but that's also clean.
Car starts, runs great otherwise, so I'm wondering what's going on.
The only thing I haven't replaced is the timing chain.

Any suggestions what else should I check?

 

My only thought is the coolant temp sensor is reading incorrectly. I've had coolant sensors send the ecm reeling to correct things. I don't think bad fuel will cause a rich condition but I'd put fresh stuff in there anyway. I'd visually check each plug to see how they look. Past that, I'd want to get a WB O2 on there just to confirm the ecm has the correct info. Maybe there's a problem in the wiring or ecm to give incorrect readings. Just some thoughts.

 

Thanks aliceempire! I checked both coolant and air temp sensor readings, both in the datalog and also with an ohm meter. The WB O2 sensor confirms the rich condition, however the spark plugs look okay. Now I'm guessing dirty injectors, but I think that would cause lean condition instead of rich but I'm running out of ideas...

 

Hmmm..and the injectors seem to be holding pressure so they don't seem too likely. Does it have emissions equipment? Really throwing this out there though I don't see it likely but EGR stuck open, sending exhaust into the intake stream? Making it read rich since there's less O2 in the intake? Clogged cat causing back pressure? Honestly just throwing idea ideas.

nevermind, I see you said it has emission delete.

 

Yes, all the emission stuff is removed, and I even disabled those in the tune.
I think I'll try some fresh fuel, new oil and maybe some diy injector cleaning. Let's see if that helps.