S-10 starting problem

start
gasoline
cylinder
chevrolet
wheels
s-10

#1

First start of the day takes a second try when tank is full. Starts OK after that. When tank is low it sometimes takes two tries during the day. I have replaced the fuel filter and put in fuel injector cleaner and water remover. It runs fine once it is started.


#2

You need to have the fuel pressure tested. The problem might be with a weak fuel pump.

When the gas tank is full, the level of gas in the gas tank creates what is called head pressure. This head pressure can assist a weak fuel pump to deliver the proper pressure and volume of fuel to the engine. Once the level of gas in the gas tank drops this head pressure is reduced. It then no longer assists the weak fuel pump to deliver the proper pressure and volume of fuel to the engine, so it takes longer to start the engine.

Tester


#3

Thank you very much. Because it runs so well after starting I didn’t suspect the fuel pump. It was replaced 3 or 4 years ago, $400.00, and it doesn’t lug down when you tromp on it.


#4

The fuel pump sometimes has redundant power supplies. The fuel pump relay is triggered by the ECM to turn on the pump for 2 seconds as soon as the key is put in the run position to prime the pump. If the relay fails, cranking the engine until about 10 psi oil pressure is reached will close the pressure switch and turn on the pump. If you don’t have a good manual with a wiring diagram it would be very helpful to get one.


#5

Thank you for the additional information.