I have a problem that I could use some insight or ideas:
Last year my 1985 RX7 GSL-SE had the "Dies above 4500 RPM" issue. I replaced the original pel pump (with Walbro GSL392 Inline Fuel 255LPH Pump ) and the fuel filter (just because I was there). That solved the problem, It worked fine all summer and fall. I probably drive the car less than 300 miles per year (it has 27K on it now). All short trips, about once a week. I start it every other week in the winter and let it run a bit (it is in a heated garage). No issues all winter.

The first time I started it this spring, it started breaking up above 4500 rpm again. I drove it a bit, but no change. So I replaced the fuel pump with the same model Walbro fuel pump (and the
fuel filter, even though the gas looked clean). Now my problem is that the car will not start.

1. Replaced the fuel pump relay: checked all the voltages and output at the relay, they seem exactly as they should.
   - In the start position I get voltage to the fuel pump and it runs: but no fuel is pumped
   - In the run/on position I get voltage to the fuel pump and it runs (mass air flow sensor flap manually opened in order to activate the "run/on coil in the relay): again no fuel is
   pumped
   - The fuel pump runs in both both positions: start and run/on - but doesn't pump fuel.
   If you are not familiar, the fuel pump relay is a "normally open" single pole relay. It has two coils that are activated independently, one operates at a time. The start and
   On positions of the key assembly control one coil each sending a voltage to the fuel pump.
2. Ignition/spark present
3. Here is the perplexing part: If run 12v from the battery directly to the fuel pump (disconnected from car circuitry): it pumps fuel and the engine starts/runs.

As best as I can tell, all the fuel pump circuity operates as intended, voltages all check out. Now, I don't know if this is true, but AI says the the voltage to the fuel pump is normally
reduced for safety and smoother operation. I wondering if the new fuel pump is "weak" and needs the the full 12V from the battery to operate. I get about 10-11 volts to the fuel pump
in each mode. I do know the mass air flow sensor has a rheostat tracking the flap positioning, so maybe that reduces the voltage. I couldn't find any shunts or limiting resistors otherwise.

Any ideas/thoughts would be welcome, and I'm open to possibly having made a mistake somewhere, so please don't worry about hurting my feelings.
Thanks,
don