Electric Fuel Pump: PSI and IP timing

[TonyS.]

My 1993 6.2l has been running for about a year with an Airtex E8153 electric fuel pump whose specs are 10-14PSI, 35GPH. After initially installing it I had noticed the engine idled faster so the timing must have advanced from the higher pump pressure. Now that I'm in the process of fitting a Racor 645 before the pump and I have the fuel lines empty I'm wondering if I should replace the fuel pump with something lower PSI, like an Airtex E8012. It specs are 5-9PSI, 30GPH. I don't want to kill my IP but would it really be worth it going to the lower PSI pump? Also, might my fuel economy increase with the lower pressure or am I off my duff thinking that would effect it? Thanks.

[TonyS.]

Well, after much reading I figure I'd be better off replacing the fuel pump I have now with a lower PSI pump. I picked up an Airtex E8012 which is 5-9PSI, 30GPH. Should be fine and maybe get me better fuel mileage than what I was getting with the higher pressure pump. We shall see.

[TonyS.]

Decided to put the Racor after the new pump so the pump pushes instead of pulls thru it. I know a lot of you guys don't like Airtex pumps but the one I had worked fine all that time before so maybe I just got lucky. :p IP timing is back to normal with this new pump. So far, so good.

[More Power]

I think you made a good choice going with the lower pressure pump.

The GM recommended specifications for lift pump pressure came from Stanadyne. Most factory electric fuel lift pumps generate on average about 7-psi with the engine idling. The minimum pressure is 4-psi (with the engine idling). Those who have monitored lift pump pressure while driving report that pressure can drop to almost zero during a hard acceleration - with a normally operating lift pump.

Jim