Fuel pump not priming/turning on when ignition is switched to "on" 3vzfe

[12340987]

My 93 es300 stumbles when I start it cold. It takes 5-7 cranks and then kind runs rough for a few seconds before it smooths out. Giving it gas while starting seems to help. I think the something is wrong, and the fuel pump isn't turning on before I start the car. I thought maybe this was by design. I jumped the DLC once on a cold engine to make the fuel pump turn on and it started great on 1 or 2 cranks.

[Jason.MZW20]

It is by design. The fuel pump only primes when ST (start in the ignition switch) is engaged. More than likely your pump is on its way out. It's usually a sign if you have to prime the pump longer to build pressure.

If the fuel pump switch in the AFM were bad, it would start and die, then not start at all.

[Mister_Perkins]

simple way to check if your pump is going bad.

1.) Check Fuel Pressure after Fuel Filter --> To Fuel Rail.
2.) Check for 12V+ To the fuel pump

If your fuel pressure isn't within OEM Spec (Low) then you are having an issue with either a pump going bad or result or a clogged fuel filter.

[12340987]

I asked a former ford tech and he said there is probably a check valve in the fuel pump that holds pressure while the pump is off. Is that right? If that is so, can it be repaired? Or how likely is it that it's the filter?

[Mister_Perkins]

Like I said, check the fuel pressure and let it sit for 10 minutes monitoring the pressure. If it drops, you have a leaky seal

Filter you more likely not be able to start it at all if it was plugged

[12340987]

I don't have a fuel pressure gauge. Anybody know if a dealer or autozone will rent them?

So if it is just a check valve can it be replaced? Seems like a waste to get a whole new pump for some stupid valve that is just giving me harder starts.