hi all my 2000 chevy blazer died on me the other day. It is looking like it might be the fuel pump. I bought the haines manual for it and was trouble shooting the electrical side. (fuel pump is not turning on) it said in the note that the oil pressure switch would act as a fuel cut off if the oil pressure got to low. When i check all the fluids in my car the oil was way below the add oil line. My question is if the oil pressure switch went is there a way to reset it? Or do i need to replace the switch? any help would be great thanks.

 

check your GROUND wire at rear of truck. mine just did same thing and it was a broken ground wire. new end and bolt back up . good to go.

 

cool thanks ill check that out.

 

I agree, check the ground. GM hasn't used the oil pressure sender to disable the fuel pump since the 80's. On your 2000, the fuel pump relay feeds the fuel pump directly, no other circuits are involved. If you apply battery voltage to the pump prime terminal in the underhood fuse panel, the pump must run:

 

98 Blazer working fine, parked it last night and this morning won't start. Sprayed starting fluid down throttle body and it fires right up. Swapped relays, tried prime terminal and still won't start. Checked ground (flat woven copper strip about 1/4" wide?) and it seemed to be attached at both ends. Can see rear most attach point but can't see other end, but when I pull on it doesn't give.

Time for a new fuel pump?

 

Sounds like low fuel pressure. Rather than guessing and throwing parts at it, check pressure at the service port near the distributor. Key ON, engine OFF, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the fuel pump shuts off. Post your results, they will tell what needs to be checked next.

 

There is no pump actuation noise when the key is turned to the ON position. It is the original fuel pump and with 178000 on the odometer, it was probably about time.

Yesterday, I depressed the Schrader valve in the fuel line test port and there was no discharge of gas, so that seem to me to be another indication that the fuel pump is not running at all.

The next step is to bang on the gas tank with a rubber mallet and if it cranks it'll be off to the repair depot.

 

need to have someone cranking engine over while pounding on the tank
if it does start dont shut it off , you likely wont get a second chance

 

Post #4 explains how to activate the pump, (your 98 fuse panel is the same). Check for battery voltage at the module connector while applying battery voltage to the pump prime terminal in the fuse panel. Also check resistance on the ground wire at the module connector to chassis ground, must be less than 5 ohms. If both are ok, the pump needs replacement.

 

I'll be trying some of the methods posted here. I'll be so glad if I don't have to replace the pump. Mine died one cold morning during warm up idling. Off to Harbor Freight Tools tomorrow for a multimeter.