i have a 89 s-10 blazer that the fuel pump has stopped working. i dropped the tank and had a friend help me, when i turn the ignition on pump runs for about 3 seconds and the relay under the hood clicks off and so does the pump. had lines disconnected so there is no pressure to cause it to stop. any help would be appreciated.

 

Kicks on for a bit then shuts off is normal, the pump doesn't run nonstop with the key on. Unless the filter is clogged hook it up and crank it. If the lines were ran dry it will take a bit of cranking.

 

ok ive cranked it and primed the carb, i heard that if the oil pressure sensor is bad it can cause it to have this problem. can someone verify this so i dont spend money i shouldnt be. the oil pressure sensor is bad it has been leaking and at idle it drops to zero pressure.

 

On the TBI engine the Oil Pressure Sending unit provides back up power to the fuel pump once pressure is built up. If the fuel pump relay is faulty or not working correctly than the oil pressure switch not building pressure would not provide power to the fuel pump. I had an opposite problem with the wrong oil pressure switch that would provide constant power to the fuel pump and the pump was running constantly even with the ingition off.

 

ok maybe ill try the oil pressure reg. i need a new one anyways

 

still nothing

 

There is two relays mounted on the drivers side fender. One is the fuel pump and one is for (I do not remember) but they are the same relay type. You could swap the relays to see if anything changes.

I scanned the fault isolation procedure from my factory service manual and attached two files. I hope this helps you with the troubleshooting.

 

Depends on the options as the number of relays. All have a fuel pump relay, a horn relay, and I think cruise control required a relay.


I'm gonna go left field for a second. Being 89 I'm gonna say its throttle body injected right? Are you guessing the pump isn't working cause the injectors aint spraying? Have you removed the fuel line while somebody cranks to see if its pumping?

 

yah line is dry at throttle body, i pulled the input line to the filter on the frame and turned the key on and nothing.

 

If you pour a small amount of gas directly into the TBI will it start and run for a little bit? If you hear the pump running and no fuel is coming out of the line at the filter you either have a faulty pump, plugged line or a seperated line. Could be the fuel line inside the tank that connects to the pump output, clogged pick up or fuel sock.

I hate to even ask, but you do have gas in the tank?