testing fuel pump(s)

Hello all, I am looking for ways to test if I have a bad fuel pump(s) without removing them from the tank? Thanks for all suggestions.

The fuel pump should come on for a few seconds to pressurize. If you can't hear it...mine's very quiet. You can check it by removing the rear seat and touching the rubber cap behind the driver's seat with one hand while turning the key to KOEO position. If you feel the pump start it's working. Unless you have a GT500 dual pump there's only one pump.

Well you have to know what they are rated at and then you can pump the fuel into a bucket for one minute. Measure it and multiply by 60 and that should let you know if they are flowing properly.

Thanks, for the suggestions.

The injectors on a mustang typically need around 39 psi so put a pressure gauge on the fuel intake line.

Depending on what year Stang you have you can plug into the OBD 2 port and watch fuel pressure, pump voltage and duty cycle while the engine is running.

Sorry, I forgot to mention that my fuel set up has triple pumps. Is there a way to isolate each pump to test them individually? Thanks.

Don't know about that. I would think you would need to pull the hat and power them up individually.

07 Boss said:

Don't know about that. I would think you would need to pull the hat and power them up individually.

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This, going to impossible to tell which one/s are running without having it out. Should be fairly simple once it's out. Just need a 12v supply and a couple of small wires w/alligator clips to touch to the pos/neg terminals of each pump. Observe safety precautions of course when working w/gas. Drain before testing; test on a bench; plenty of ventilation; use a small tub. Keep outlets pointed away from you, etc...etc.

That's what I figured I would have to do, but wanted to see if I was unaware of a way of testing them in the tank. Thanks.

Do they not have connectors on top? (I’ve never actually looked at the pumps in these cars) Could you not unplug them all and then just plug one back in at a time?

Forty61 said:

Do they not have connectors on top? (I’ve never actually looked at the pumps in these cars) Could you not unplug them all and then just plug one back in at a time?

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They're usually daisy-chained together with one connector at the top of the fuel hat. Hence, the reason you have to take the fuel module out of the tank and test each pump individually. If I were in your shoes I'd look at putting together a walbro using a standard pump body. Should only cost ~$150 at most.