1993 Chevy S-10 3 fuel pumps in 3000 miles

STRAYKATZ

MEMBER
1993 CHEVROLET S-10
6 CYL
4WD
AUTOMATIC
171,023 MILES

This is a blazer 4.3 cpi. Replace the fuel pump and sending unit assembly about 9000 ago 1 year (original wires burnt in the tank). While on vacation it Would not start after driving 4 hours and let it sit for 20 minutes and it started but crank over for about 20 second before it started, replace the in line fuel filter and it was plugged. Ran ok for about 300 mile(on vacation) that started starving for gas and slowing down on the freeway. Had a new Delphi pump installed, seem ok for about 20 miles but didn't start right up as normal, then it started starving again and got 44 code and tried new O2 sensor. Still the same starving. When the pump cools down 20-30 minute it would start and run ok but after 20 to 2 hours it starts starving again. Replaced cat and muffler, fuel pressure regulator. Put in an airtex pump and sending unit assembly and it lasted about 2500 mile then started starving again replaced the pump again with an other delphi and was good for about 200 miles and it stated cutting out, like ignition being turned on and off, and starving. Fuel pump was making load noise, let it cool for 2 hours and started up. When all of this is happening it starts hard cranks for about 15-20 second if it starts and it is not rich but lean when it starts, has very little or no fuel pressure. Check with a gauge 0-6psi when not starting, 54-60 when it starts ok, the fuel tank always has enough fuel to completely cover the fuel pump, not just the strainer. I also have a problem with AC working intermitantly and the high pressure cutout switch has burnt wires. I only mention that too because that may have some connection. Hope someone can answer aand help me

1 Reply

JDL

MECHANIC
16,098 POSTS

Hello, I'd have to check actual voltage reading voltage at the fuel pump, when the problem occurs. Can you test the voltage circuits at the fuel pump relay? There shows to be an oil pressure switch in the fuel pump circuit, parallel to the relay. An extended crank may mean the pump is getting voltage from the o/p switch not the relay. The extended crank because the oil pressure has to build some before the switch will close.

There shows to be a fuel pump prime connector, it's a test connector for the pump, you can run the pump without using the key. Looking under the hood, a little left of center on the firewall, gray wire with electrical connector, nothing plugged into it. If you use a jumper wire and run B+ to the connector, the pump should run, use an inline fuse.

All the pump manufacturers you mentioned have web sites, they will talk to you about their pumps. I have talked to airtex before, haven't talked to Delphi.