I did not want to hijack the other recent 5.0 TBI hard start thread but to explore what Clinebarger posted about testing the fuel pump relay and prime wire
My 1993 K1500 has a longer crank first start when cold but starts quick when up to temp. How long? Well several seconds before it will catch. Possibly this is 100% normal on this worn out old girl. But for fun I began researching what he was saying on this and began playing around.
Vehicle running, fuel relay unplugged and the vehicle stays running. This means the oil pressure switch is good. Now after researching the red prime wire, I could not find the loose wire attached to the wire loom near the fuel pump relay but after reading some wire diagrams I found it connects to port G on the OBD1 port. He stated that there should not be power to the wire when the engine is running.
So I tested with my auto ranging multimeter, which as fool proof as it is, I am still new at. So: Truck off, ignition off: 5 millivolts DC. Truck running, relay in place: It fluctuated between 24-34 millivolts. Truck off, ignition off and relay removed: 0.5 millivolts. I used port A as ground.
I suppose next step is to test the relay with a power source or replace and see if it improves. But on the flip side, I have not tested my fuel pressure so perhaps the vehicle is otherwise fine.
As a caveat, I am not willing to throw money at the truck and am really enjoying learning about basic trouble shooting, electrical and so on. Just a fun project.
My 1993 K1500 has a longer crank first start when cold but starts quick when up to temp. How long? Well several seconds before it will catch. Possibly this is 100% normal on this worn out old girl. But for fun I began researching what he was saying on this and began playing around.
Vehicle running, fuel relay unplugged and the vehicle stays running. This means the oil pressure switch is good. Now after researching the red prime wire, I could not find the loose wire attached to the wire loom near the fuel pump relay but after reading some wire diagrams I found it connects to port G on the OBD1 port. He stated that there should not be power to the wire when the engine is running.
So I tested with my auto ranging multimeter, which as fool proof as it is, I am still new at. So: Truck off, ignition off: 5 millivolts DC. Truck running, relay in place: It fluctuated between 24-34 millivolts. Truck off, ignition off and relay removed: 0.5 millivolts. I used port A as ground.
I suppose next step is to test the relay with a power source or replace and see if it improves. But on the flip side, I have not tested my fuel pressure so perhaps the vehicle is otherwise fine.
As a caveat, I am not willing to throw money at the truck and am really enjoying learning about basic trouble shooting, electrical and so on. Just a fun project.
