fuel pump info

[teach1]

I just had my 96 astro checked out because of hard starting problems. I had replaced the cap and rotor, and also the pulsator on the fuel pump. I was getting 52psi on initial key turn and then working up to about 60psi. The flow was fine. The mechanic had a program that tested the pump circuit and showed me that the pump was only drawing 7.2 amps and should have been around 9amps. He said that the pressure HAS to be 60psi to trip the regulator and fire the injectors. He said they developed this testing because they kept getting okay readings and the vehicles wouldn't start. He also stated that very specific pressure requirements have been common in Europe for some time, but we Americans have been a little lax in our testing.

The reason for the low pressure was burnt brushes in the pump. He also stated that the fuel is a lubricant and a coolant for the pump and that you need to keep 1/4 tank or more of fuel to keep from hurting the pump.

Hope it helps others!!

[LTJGWorth]

I had heard about the fuel pump using the gas as a coolant. Stupid design I think. I've run mine empty before and I haven't had a problem with it. But it's a 92 so it may be a little different.

[CD Smalley]

It's true on the pumps using the fuel to keep thm cool at least on the GM vehicles. My father-in-law went thru several pumps on his pickup before the dealer mechanic and he talked. Mechanic found out the gas gauge didn't work in the truck either. Well go figure why he was burning up pumps about once per year. Keeping it nearly full has kept the last pump going for years....