testing a fuel pump

[24flys]

hey guys,

how do i test a fuel pump that is out of the car to make sure it works. it came out of a 1.7. let me know

thanks

scotty

[bd1308]

well....i assume there are just power connections for 12V and ground. You gotta watch though, these pumps rely on liquid to be cooled. So you have to pump something....I guess gasoline, or water? I dont know somebody help me out. I just know it needs to pump something.

[BigD9146gt]

NOT WATER! It probably wouldn't hurt it, but why take that chance. Getting water in there might start some corrosion that the gas couldn't get out. Its just a little more work to get a bucket of gas and hook up a few lines. If you have a pressure gauge, you can test the pump. Get the fuel presure regulator off the motor and hook the D (drunk/pressure) part of the pump to thte fuel pump and then to the pressure gauge, then teh gauge to the regulater, and then you need a T fitting from the regulater back to the R (rutch/return), then a line to the S (all i know is htat it sucks) to the gasoline.

Dave D, is that right? i forget where the last post you did that had the definitions for the pump lettering

[bd1308]

your right....i didnt think I need more sleep or something

[914GT]

I've run water through them to test them out. Doesn't hurt them. I've had them apart and they're pretty simple mechanically. Run through some paint thinner to flush out the water and prevent any corrosion.

[BigD9146gt]

Good call Guy, i guess i'm alittle too paranoid. I just think of the cost of one new, thats all.

[914GT]

I was doing a lot of bench testing with one, to lower the pressure for a carb. I didn't want to mess with gasoline. You're right though, for a quickie test probably best to use gas or maybe thinner, kerosene, etc.

[srb7f]

Anybody else think that connecting up and electrical device next to an open bucket of gasoline is a bad idea? My advice would be to really spend the time and make the proper setup with hoses, clamps, and a contained fuel source of some sorts before you go plugging things in. Make sure you have a fire extinguisher beside you just in case something should happen. Good luck and be careful. Steve

[bd1308]

yeah alarms are goign off in my head....all you need is a spark arcing from those contacts and well....thats why i said use water. But I guess cost would factor in...I dunno I would use water and then use thinner. Works for me in my mind

[Dave at Pelican Parts]

If you're just checking to see if the pump works, hook up power and ground to the electrical connector with some alligator clips. Have rags or something around the fuel fittings in case any spits out. Just run it for a second, all you want to know is if the pump motor spins.

Don't try to choke down the stock FI pump to carb pressures. It doesn't really work in the long term. I know more than one person who blames an engine-bay fire on trying to do that very thing (and it failing after a while).

--DD

[914GT]

Originally posted by Dave at Pelican Parts
Don't try to choke down the stock FI pump to carb pressures. It doesn't really work in the long term. --DD

You're right, you cannot do that. The only way you can do it is to remove one of the two springs in the pump's pressure relief valve. You can then regulate it down to about 10 psi, then put an external regulator to further dial it down to about 5 psi. This works, I ran with it for a while before I went to a stock Chevy mechanical pump.

[BigD9146gt]

Originally posted by srb7f
Anybody else think that connecting up and electrical device next to an open bucket of gasoline is a bad idea?... Steve

1. Hollywood has a great imagination (and CGI)

2. for safe measure, hook up the fuel pump first, set it on something, and have the +/- leads be a few feet long and hook up to a battery behind a small wall, away from the gasoline.

[24flys]

can you test it with a car battery or will it overload it.??

scotty

[Dave at Pelican Parts]

Test it with a car battery. It's set up to run on about 12V. But don't test it for long without fuel in it--just long enough to hear it buzz is fine.

--DD

[kycarguy 935]

We use to have a mechanic at our shop drain the gas out of full gas tanks with a bosch fuel pump and 12 volts and he would drain them into a plastic jug with a fuel line that would fit in the hose of the plastic jug.