92 S-10 Blazer, 4X4, Two-door, 4.3CPI, Auto trans.

Well, after replacing a failed fuel pump, and then replacing the sending unit, the truck starts and runs again. However, I am suffering from excessive cranking times. I can hear the relay click, but, the fuel pump does not run for the "prime" couple seconds. I have to crank the engine till oil pressure comes up to get it to start. I explore the fuse block, and did not see anything obviously talking about the fuel pump, both ECMA, and ECMB are good. I do not have a manual for the truck, even an owners manual.... so, I am turning to you folks for a little enlightenment. (all this started immediately after replacing the pump/sending unit.)

Is there a fuse for the Fuel Pump? If so, where is it hiding?

What else could possibly give these symptoms?

Any help would be appreciated.

 

No one has an ideas here?

 

does the fuel pump relay 'click' when you(or somebody else) keys it on? The relay(b-4 you ask) is on of the two or three, on the firewall, near the master cylinder. It needs the pulse/click when you key it on. Little black box-1 inch square. good luck jp

 

Checked the relay, and it does indeed "click" when the key is turned on. It appears that the relay/ecm control is working as it should, however, the pump does NOT run for the prime when the key is turned to the on position. I have not been able to test it, to see if there is actually power coming OUT of it for the prime.....

 

did it start the right way before the pump you replaced died? I would check the wiring at the pump because there is a wiring kit you should use when replacing it. Especially if its all rusted. If the ignition key an relay work ok you may have a bad pump. It happens...........

 

if the pump doesn't hum when keyed on I would prod out the wires coming out of the relay-the one that clicks. One of these wires will 'energize' for 2 seconds after key on and this wire(although it may change color at the rear of the vehicle)-will make it's way to the rear of your truck. If you don't have 'juice' in the rear, somewhere along the way you lost it. You may have to check a schematic-if questionable. You could run a temporary jumper from front to rear for a test but that's the angle I would be looking at. jp-had one like this years ago.[:-]

 

Having a look at the schematic for the fuel pump would be very nice, wish I had one.... If someone could post one, I would greatly appreciate it. (should include the oil pressure switch as well..) I am kinda curious where the OPS, and Relay wiring come together, as I would suspect that the problem is somewhere in there, per the symptoms....

Yes, this problem started immediately after replacing the pump, and sending unit. The truck runs fine once it is started though, so I don't think it is a bad pump....... also, starts easier once warmed up, but still, a bit of crank time, just not as much as when cold.

 

Simplistic, but best I could find.

 

Cool, thanks for the schematic. Rather intriguing.

Is the "Fuel Pump Test connector" At the ALDL? It appears that is where the wires join. Could I probe there when the pump primes at initial start up to verify I am getting voltage THRU the relay?

I must admit, it seems odd to me that the power wire coming out of the relay, would come back inside, just to go outside again..... maybe it's just me?

 

just a random thought...if this issue started right after the pump install, myself, I would be looking at all areas around the install. Could be coincidence or not...keep us posted. jp[:'(]