I was going to help a friend with his 502 project today, and spent hours trying to figure out why the bin I built for my Ramjet running a 7730 S_AUJP ran pig rich, BLM 96 INT 96.

Some time we forget the basics. What I found is that the early Ramjets ran a fuel pressure regulator from a Olds 4.0 that set rail pressure at 41lbs to 47lbs. The Ramjet MEFI4 502 uses the regulator from the 454J 96 to 2000, rail pressure 58lbs to 62lbs. Installed Olds reg and problem solved.

 

With EFI, you didn't really need to change the parts - just change the injector flowrate in the bin to match the real flowrate...

 

I guess I'm just old school, old GUMMPY used to preach don't lie to it tell it what it is and work the tune out. I did change inj constant and when I saw how far I had changed it I needed to find out why.

When I figured out what GM had done, replacing the regulator was a quick and inexpensive fix compared to rebuilding the VE tables.

The other reason I posted this find was to inform the other RAmJet owners of the change of regulators. I found when you call any of the GM performance suppliers with the PN it will update to the latest part.