Ok,
So I need some help.
So it's not driving yet. turns out it hasn't been quick and simple to solve this fueling issue... And I could really use the help because it's otherwise done.
So the current fuel systems is the 1994 5sfe fuel rail and injectors, modified with the fuel pressure regulator removed off the end of the rail and replaced with the "cap" that came from the injector rail off of the old 3sfe. I did this because the regulator on the Rav is in the tank. I assumed this would be good enough as I have started and ran the car. The issue is that the car doesn't stay running for very long, like maybe 15 to 30 seconds and it shuts off.
So in trying to solve this issue, I have come up with a couple theories and have done some research. This guy had a similar problem, but never got any answers.
http://www.rav4world.com/forums/85-4-1-fau...ifferences.htmlBut the issue is similar.
The 5s has the 23250-74100 injector

The 3s came with the 74140 injector (Could either be because of Cali emissions or the Returnless Fuel System)

On the bench

So my theories of operation are this, keeping in mind that it does run, but very shortly. When it dies it will not restart for several days really. You cant get it restarted in the same day (why I think it's fueling)
1) the 74100 injectors don't like the fuel system being set up that way as a returnless (although you would think fuel pressure should be fuel pressure) The solution here would be to make the system a return style system with the old FPR installed back on the rail running a new line to the tank. Of course removing the FPR that is currently in the tank.
2) The 74100 injectors don't like the electrical signal being given to them by the ECU (maybe a high vs low impedence thing) and will run for a moment, but not enough to sustain. Maybe there is some sort of resistor that could be soldered in? Both injectors measure the same 14.3 Ohm's of resistance however.
3) It runs for a minute and dies out because of a bad Oxygen sensor in the exhaust header. There was a bad sensor in that header that I never got replaced before the 3s crapped out. If it is sending wrong or mixed signals this could be the issue. But again, why doesn't resetting the ECU fix that issue and give me another 30 seconds of running? I don't know which sensor it is, but could figure it out or just change them both.
Are there any theories?