Car in question is a bone stock 95 SC300 automatic that has not been used for a while.

After running the car low on gas and sitting there it would be hard to start, stumble and want to die. I figured that i overheated my walbro, so I replaced it with another fuel pump.

After install, the car would crank and crank but it does not fire. I noticed that I do not hear the fuel pump prime, till after I crank the car.

I suspected the fuel pump ecu, so I jumped the FP and +B signal on the diagnostic port. As soon as I crank the key to ignition on, the fuel pump primes and runs, constantly, non stop. However the car does not start. I swap fuel pump ecu's with another, and same issue. It does not prime at all until you crank the car. If I jump those 2 ports, fuel pump primes and primes, but no start.

Under the car when I jump the diagnostic port I can feel and hear the fuel moving at the fuel filter, I can feel the gas going through the fuel filter, and I can feel the gas moving in the line past the fuel filter.

However, somehow I am not getting gas to the fuel rail, I can't feel the gas moving neither where the fuel return is, nor fuel line to fuel rail. Prior to my fuel pump replacement, car ran, but poorly.

This does not make sense to me, how can Feel the gas after the fuel filter, but somehow not make it to the fuel rail? Is there any other filter etc I am missing? Car started prior to fuel pump change, just ran extremely lean. Now the car does not start, and new fuel pump works for sure.

Any ideas, anything that can block gas, between the fuel filter and the fuel rail????!

PS. On the past I have jumped the FP +B ports on the diagnostic port. The fuel pump would prime at the on position (not crank) and stop just like if I had a working fuel pump ecu . Now it runs non stop if I jump the port, or only in crank position if the ports is not jumped.

 

Maybe its not a fuel problem.. Check your plugs and maybe ohm out the wires... You probably have a broken timing belt.

 

Timing belt was replaced less then 10,000 miles ago, highly unlikely... And the car did start with the old pump.

 

Fuel Pressure Regulator on the fuel rail. Assuming you diagnosis of fuel flowing to the rail and not out the return line is correct. That is the only thing that would stop that up.