Stumped by my 1997 Blazer!

I have a 1997 S-10 Blazer 4.3L. Last winter I replaced the fuel pump. Yesterday it stalled and died on hwy 25 miles away from house, grrrrr. The odd thing is about an hour after I got it off the Truck, my wife turned it over and it started and ran for approx. 5 minutes then died. Hasn't started since. The fuel pump is cycling w/ key to on position and building pressure at the schraeder valve. I replaced the relay for giggles(no luck) and had it scanned w/ a cheapie OBD II scanner, no codes. Any Ideas?

Use a fuel pressure gage. look for correct pressure and that the pressure doesn't drop like a rock when the key is turned off. Right now, I'm thinking fuel issue? Also, when the problem occurs, if it cranks good but won't start, have a helper crank it, while you visually check for spark at the plugs. Is there a security system on the vehicle?

THNX JDL for your quick reply, here's where I'm at since yesterday afternoon, sprayes carb cleaner in intake and she fired up, so ignition eliminated. Bought fuel pressure gauge and she only builds 40-41 psi instead of 55-61 that Haynes says is required, next I need to tap into line and check pressure before fuel filter to verify it's the pump. Assuming it is, any fuel pump brand recommendations? I put in an Airtech one 4-5 mos. ago got it for $65 online when o'reilley's wanted $280 for same one. Which is still better than approx. 600 that Chevy wanted for the Goodwrench part.

Before condemning the fuel pump, ascertain that the pump has the correct voltage AT THE PUMP. There is a TSB regarding the electrical connectors and ground in the pump power system and the problem is more common than is widely known.

http://www.wwdsltd.com/files/PumpConnector.jpg

BB, Any Idea where to find the spec voltage at the connectors? guess normal 12v, but not sure, I would assume that if less than spec that would cause the pressure to be there but low. I did put the supplied replacement connector and new harness on when I put the airtex pump on in december.

I agree with BB, check voltage and ground at the pump connector. Take a voltage reading across the battery posts, engine cranking, the reading at the fuel pump should be close to the same, as far as voltage. Do you have the spider fuel system? Usually the pressure spec is higher than you listed?

believe so it's the 4.3 vortech, the pressure spec was from my haynes manual, csefi system according to haynes.

For the spider fuel system, MOD says 60--66 psi?

Toss the Airtex pump in the trash, right on top of the Haynes manual. With Airtex pumps, 5 months is considered good, (they're junk). Same goes for Haynes, they don't have a clue. Most of their information is either outdated, missing, or in this case, wrong.

As Blue Bowtie mentioned, check the connections both at the module, and in the tank, at the pump. You probably won't find a problem though, the pump motor or the check valve usually go long before the wiring has a chance to burn ;)

All 96 and newer 4.3L CSFI fuel pressure specs are as jdl mentioned, 60psi to 66psi with the key on, engine off, and the fuel pump running. Pressure must remain above 55psi for 3 to 5 minutes after the pump shuts off. Replace the pump one time, with an AC Delco and be done! They are more expensive, but it beats replacing the pump every few months!