My Daughters 94 Buick sometimes won’t start in the am. Have changed fuel filter and out in dry gas ???
“Sometimes won’t start” is not very descriptive.
Does the starter turn the engine over, but the engine fails to start–or does the starter not engage?
How old is the battery?
When were the spark plugs last changed?
What is the typical ambient temperature when the no-start condition takes place?
First thing is to separate if it is a fuel or spark issue. Check for fuel pressure when it won’t start. If none, may have a sticky injector, pump going south, pressure regulator, etc. If no spark, then a whole 'nother deal.
Sorry I wasn’t very descriptive. Motor turns over. Fuel pump doesn’t always turn on. When it does it starts. Ambient temp, does it in the summer and the fall. Computer sending signal to fuel pump relay. Hot wired fuel pump still would not start. About once a week it doesn’t want to start
If the pump didn’t run when you “hot wired” it, it sure sounds like the fuel pump is the problem.
…assuming you wired it correctly
You haven’t ruled out fuel or spark as the problem. Hot wiring the fuel pump didn’t rule out fuel pressure, fuel injector action, ignition, or spark, as problems.
Eliminate one possibility at a time. Start with fuel. Measure fuel pressure. When cranking the engine, hold the gas pedal to the floor, ease up as (if) the engine starts. If it, then, does, the engine was flooded. If that wasn’t it, spray Starter Fluid into the intake tube during start. If it, then, runs for a few seconds, that shows that fuel injectors aren’t spraying fuel into the cylinders. Test fuel injectors.
You probably know how to check for spark, from the end of the spark plug wires.
Try turning the key to “on” for four seconds or so every morning before turning it to “start”. See if the problem disappears.
I’m wondering if an intermittant leaky injector is allowing air into the line and allowing the gas to drain back into the tank. Turning the key to “on” first will repressurize the line.
Well it finally did not start at all in the middle of testing. I even checked for voltage drop at the pump connector. It was the fuel pump. Thanks for all the ideas they helped.