Adventures in troubleshooting

Went to start the SS a couple of days ago. Haven't driven it in at least a month. Need to take it for E test and tags. No start. Fast crank, no catch. No prime with key on. Uh oh. Put the pressure gauge on it. Zero. Doesn't do anything when I use the jumper, either. Ok, no big deal, the fuel pump lasted twenty years.

Decided to test the gauge by checking the Caprice wagon while I'm at it. Some of you know that I have been dealing with a DOA condition on that car that I traced back to ICM issues, throwing a code 42. Car died back in Jan on the way to work. Replaced ICM/coil with spare, car worked. Driven once or twice between Jan and June. Took it for a drive a couple of weeks ago, car died. Replaced coil/ICM again, car runs, but stalls eventually. So... put the FP gauge on it, and lo and behold... 40psi at prime, below 40 after start, steadily bleeds off until stall.

Pump and sender were new a year ago!

So... pump? Or... clogged fuel filter?

[You must be registered and logged in to see this link.]

Fuel pressure should increase when revving the engine, not decrease. Of course, you already know that I'm going to say, replace the fuel filter first, it's the cheapest item. You did change it when you put the new pump in right? I would expect more that a year out of a filter especially if you haven't been using the car. If you used a good AC Delco pump I would also expect it to last more than a year also. Based on what I'm seeing here I would have to say that you are losing voltage at the fuel pump, whether it's a bad ground, faulty relay or high resistance in the power feed to the fuel pump, I'm not sure. Run a voltage drop as close as you can next to the fuel pump, without dropping any thing to access to determine what is going on in the fuel pump circuit. Common problem is a burned connector inside the fuel tank at the sender assembly. As the circuit gets hotter, resistance goes up in the connector, further decreasing the available voltage to the pump. In turn causing a drop in fuel pressure and eventually stalling the engine.