98 chevy silverado

It starts if hot out but not when cold whats with this thing lol

I had similar symptoms with 1997 c3500. Is fuel pump relay operating? When you turn on ignition, you should hear relay under hood click on, then, after a couple seconds, back off. Is power reaching fuel pump connector? Remove fuel pump relay under hood and jumper from armature to N.O. contact to apply constant voltage to fuel pump wire. Identification of relay internal connections is printed on the side of the relay. Terminals of relay are labeled on the bottom of the relay. I used a bent piece of paper clip for this jumper. Confirm voltage reaches the hot wire to fuel pump and fuel gauge sender harness to fuel tank under truck. Is fuel pump power connected through connector at fuel tank harness? Measure voltage present on heavy grey wire on tank side of the fuel tank electrical connector with meter or test light. I had an issue with connector pins in the connector not securely seated in connector. Some previous mechanic had tried to disconnect the wires at rear of connector shell instead of properly disconnecting the connector and did not seat one of the pins properly back into connector shell. Is ground wire making good connection to vehicle frame? A bad ground connection will put voltage on the heavy black fuel pump ground wire. Only three of the four wires into the fuel tank go through the connector to the vehicle wiring harness. The fuel pump ground return on the fourth wire should have a ring terminal. This must be securely grounded to the frame with the screw which mounts the vehicle wiring harness side of the electrical connector. The fuel pump pulls quite a lot of current and resistance in the ground wire connection can stop the fuel pump. I also had a problem with the ground wire connection because some previous mechanic had over torqued the self tapping screw holding the connector mounting tab and ground ring and stripped out the hole in the chassis where the ground wire and chassis harness connector were bolted to the frame. Without removing the truck bed, drilling a new hole is blocked by bottom flange of C beam frame. It causes a royal PITA because I now must use a bolt with nut in place of the self-tapping screw . It makes removing and replacing the gas tank much more difficult than it would have been, which was more than difficult enough without this extra added complication. If the heavy grey wire has voltage with relay socket jumpered and the ground wire is grounded, then the problem is inside the gas tank. You need to remove the gas tank. Remove the fuel pump and gauge sender assembly from the tank. Carefully check the pins in the connectors inside the tank. Discoloration of the contacts or melted insulation of wires next to connectors indicates poor contact in the connector. If the connectors have over heated it will have softened the temper of the contacts such that they will not apply sufficient contact pressure to ensure reliable connection. If this occurs on the connector carrying power through the top of the tank, you must replace the entire assembly of pump and gauge sender to ensure reliable operation. Make sure you test the fuel gauge sender and pump on the new assembly before installing the assembly in the fuel tank. Replacing the fuel pump and fuel gauge assmbly in the tank fixed my fuel pump but lost the fuel gauge. Fuel gauge sender in new fuel pump and fuel gauge sender is defective. I should have tested for fuel gauge response before installing the harness in the tank. Next time I remove the gas tank, to fix the fuel gauge sender, I will insert a pair of connector crimp lugs on the ground wire. Unfortunately this adds three more points of failure to that wire, the connections from wire to connector on each side of connectors, and the connection between male connector to female receptacle. I would not try this without a ratcheting style crimping tool adjusted and tested for wire gauge and terminal size.