Starting issue

[Brayam]

Hello I have 1988 k1500 5.7. it had an on/off switch for the fuel pump & it was taken off by a mechanic & now it takes a couple of cranks for it to start. I drive it around the block, turn it off & back on & it fires up right away. Does anyone know what can be the problem? TIA

 

[Komet]

Hook a fuel pressure gauge up to it and see what sort of pressure it makes with the key on, and how fast it bleeds off.

 

[Dud1f3r]

Hook a fuel pressure gauge up to it and see what sort of pressure it makes with the key on, and how fast it bleeds off.

This. Sounds like it's slow to build up fuel pressure, but once the fuel pressure is there, it holds fine. I'd check the wiring the mechanic did and see if they used too thin of a wire. Not enough current going to the pump == slower pressure build up speed.

 

[Erik the Awful]

it had an on/off switch for the fuel pump & it was taken off by a hack & now it takes a couple of cranks for it to start.

FTFY. I'd take the time to fix it right. If that doesn't fix the problem do some diagnosis, starting with checking the fuel pressure.