Intermitent Astro Fuel pump

1992 Astro VIN Z

Drove it to work on Monday. Was there for about 15 minutes before I decided I didn't feel good and needed to head home. Went back to van and it wouldn't start. It would crank and crank. But wouldn't fire. I couldn't hear a buzz from the fuel pump either. Had it towed to the house. I had to take the battery out of the van and put that into another car so that I could get my wife and I to work.

Tonight I was able to put the battery back into the van. It fired right up! I could hear the fuel pump buzz and everything. After letting it idle for 20 minutes or so I shut it off. I tried immeditately to start it and got nothing again. Cranks but won't fire. I hear no buzzing from the fuel pump.

So I figure it's either the relay or the pump itself.

How should I go about testing the relay before I just throw a new pump into it???

Easiest way is to disconnect the connector at the tank and install a test light on the gray wire.
Have someone turn the key on..test light should come on and go off after 2 seconds...then spin the engine over..the light should come on and remain on until the key is turned off.
If the light comes on then you have tested the complete system up to that point and I would suspect a bad pump or connection

Somethign to remember here si that the GM vehicles typically use an oil pressure switch in parallel with the relay. The computer operates the relay, the switch sends voltage to the pump directly. The computer also has a monitoring system which checks the relay's response to the computer's relay signal. If the relay does not respond, a code is set, indicating that the response circuit did not respond. If this code is set, I would suspect the relay, or its control system.
The problem here, I believe, is the pump itself. The oil pressure switch will send voltage to the pump directly, bypassing the relay. If the engine failed to start even when cranked sufficiently to create oil pressure, the problem is likely the pump itself, or the feed wire providing voltage to it. I would also check the pump ground, before replacing the pump. Ray

Checked the relay per the FSM. It seems fine. Tried to start again tonight and it still just cranks.

So right now I'm in the process of syphoning the gas out, nearly full tank BTW, and will start in taking things apart further tomorrow night. Hope to have it all done and running by mid day Saturday.

Thanks All!

Well here it is 5:10PM CDT. The van is done. The tools are put away. But I'm still greasy, oily and smell like gas.

But it runs!!!

WooHoo!!