The pump assembly is a Spectra. Specs appear to match stock flow, but in one listing pressure is shown as 87-116 PSI, which would not match factory unit. But the unit pricing would not appear to be anything other than a low price stock replacement. Looks like a very recent replacement.

What was the pressure when the pump primed, before it shut off and dropped to 0? Check pressure at idle with vacuum compensation line off the pressure regulator. Spec is 43.5 PSI, with a range of 41-47 PSI being acceptable. Reattach the vacuum line. Pressure will drop 8 to 10 below the “no vacuum” value with a stock cam. Will drop less with a more aggressive cam. The PCM has no control over the fuel pump, except allowing it to restart after the key is turned to “START” and the PCM receives the “fuel enable” signal from the PASS-Key II security system (VATS), and the PCM receives the low resolution cam position signal from the sensor in the Optispark distributor.

The application chart for the Accel 23 #/HR injectors shows they are for 92-97 LT1. Odd, because 92/93 should be 22 #/HR, and 94-97 at 24 #/HR (programmed in PCM as 24.9 #/HR). Accel injectors are not known for their quality.

Toggle switch probably arms the N2O system, push button for purge. Are there any remnants left of the nitrous system fuel and nitrous plumbing?

Best way to solve the running rich problem is to run a data log of the PCM using Scan9495, free download here, with advice on cable:

https://www.camaroz28.com/forums/com...95-lt1-874306/

 

You posted the photo while I was typing the above response. See comments above. Without removing the bucket that contains the pump, hard to tell. But most likely it is a new Spectra aftermarket replacement.

 

before I go buy a pressure tester for $150 and while I wait for my aldl cable to arrive, is it possible to just swap the PCM from my other car? Assuming it’s a tuning problem? Because the previous owner thought it ran good but when I talked to him more about it apparently it’s been running super rich the entire time he had the car and thought it was normal.

 

You don't need to spend $150 for a pressure test gauge. Something like this should be $30 or less. The Scrader valve is a -4AN connection. I've had this one since I bought my Formula 27 years ago.

https://www.camaroz28.com/g/picture/12591068

Generally, you don’t “tune” for a wet kit. You optimize the tune for max performance on straight motor, then use external means to tune for the nitrous. You use something like an MSD Digital 6 to retard the timing on nitrous, and use the fuel jetting to provide the correct amount of fuel for the added nitrous.

Since it's relatively easy to swap the PCM, it’s worth a try to see if it fixes anything. If the PCM that's in there now is programmed for stock injectors, and they put in 23’s, that’s nothing the PCM can’t correct with the long term fuel trims. Rapid loss of fuel pressure after prime can indicate a leaking injector (or several). Exhaust leaks before the O2 sensors, faulty O2 sensors, or excessive misfires can cause it to run rich. When you say the stock fuel pressure regulator is not leaking, did you check for fuel in the vacuum compensation line? In checking the plugs are they all fouled, only one bank fouled, or only some fouled in a random pattern?

 

so I slapped the car back together last night after replacing the radiator, PS pump, some missing bolts, and cleaning up a bunch of connectors and other parts and it runs great!!!!!! No idea exactly what I did that woulda fixed it and I expected it to run the same way it did when I put it on the jack stands but mystery solved. I appreciate all the advice.

 

Curious which connectors you cleaned. Did you flush them with IPA or just compressed air?

 

all of them. With some CRC connector cleaner from Oreilly’s. I also replaced the opti harness because the weatherproof sheathing was missing and disconnected the O2s. Not exactly sure what made it run again or if it was a combination of the 30 hours of work over the past week but it’s SUBSTANTIALLY improved, without throwing unnecessary parts at it. Just some thoughtful stuff I acquired from doing the same to my z28 last year which had its own laundry list of problems. Ironically I didn’t do the oil pressure/level sending unit or whatever it is and the oil pressure gauge is all whacked out and dances around.