fuel pump & voltage troubleshooting

N1446 · Post by **N1446** » Wed Jul 22, 2009 6:12 pm

i got everything together after the car is sitting for a while , I ve read the legacy fuel pumps "give-up" after sitting for extending periods for what ever reason , i pulled the rear seat and tested the voltage on the conector from the loom under the seat and on the pump and there are like 5 pins in a 6 pin connector or somthing - i turn the key to "ON" and no-sound , voltage is to the pin on the pump @ 2.63v , 7.01v .30 v.10 v and 0.01 v - all equal to approx 10 volts is this accurate to say with the key on the pump is dead ?

ericem · Post by **ericem** » Wed Jul 22, 2009 7:32 pm

i think you should start the car should work just fine.

N1446 · Post by **N1446** » Wed Jul 22, 2009 8:04 pm

here s an idea
u stand on the front bumper and dump fuel in the motor while i play with the gas

N1446 · Post by **N1446** » Thu Jul 23, 2009 1:16 am

seriously though is the pump toast or is it salvage-able ?
with power to the pump no noise - no click - not anything- no start

n2x4 · Post by **n2x4** » Thu Jul 23, 2009 3:31 am

Take the pump out of the tank and apply 12V directly to it, if it goes, you know it works.

If it works then, but not in the car, you've got a bad fuel pump ground. This was a common issue on the Legacy. The ground wasn't big enough and tended to burn up.

ericem · Post by **ericem** » Thu Jul 23, 2009 4:07 am

once it primes it shuts off right ?

N1446 · Post by **N1446** » Thu Jul 23, 2009 5:00 pm

i m convinced it doesn t get charge at all
i sit in the car with all windows and doors shut and i fold the rear seat down and remove the pump cover then switch the key to "ON" .. but

silence .. , the car will crank forever when i turn past "ON" w\c no fuel

no click or humm or anything , just quiet at the tank and i ve verified there is power to the connector on the pump

i will test direct 12v to be sure

Post by **Legacy777** » Thu Jul 23, 2009 7:38 pm

Test the voltage at the pump with the engine cranking. key in the "START" position. Make sure you have the correct leads/pins.

If you have no voltage, figure out why you don't have voltage, rather than trying to yank the pump out. The pump isn't going to go bad if it sits for an extending period of time.

N1446 · Post by **N1446** » Thu Jul 23, 2009 10:29 pm

ok the pump runs off direct 12v
when everything is connected in the car it will not turn on in the ON position even though there is voltage present - approximately 10v
the car is meant to presurize the line when its in "ON" correct ?
-
is there a relay or fuse that is connected to the ignition that maybe be the cause ? : i m sure the grounds are correct as they have not changed and there IS voltage to the pump whne turned "ON"

asc_up · Post by **asc_up** » Thu Jul 23, 2009 10:50 pm

There's a fuel pump relay in the dash. It's kind of a bitch to get to, but it's really not that bad to replace. I believe the one I got from the dealer cost about $30.

N1446 · Post by **N1446** » Thu Jul 23, 2009 11:05 pm

is it up under the steering column area ? the Haynes FSM i have has next to nothing in it for Fuel system troubleshooting

Pic ?

asc_up · Post by **asc_up** » Thu Jul 23, 2009 11:10 pm

Searching is your friend

http://www.surrealmirage.com/subaru/fil ... tion03.jpg

N1446 · Post by **N1446** » Thu Jul 23, 2009 11:41 pm

Sick
Thankyou asc_up
it will be nice to find the gremlin

asc_up · Post by **asc_up** » Thu Jul 23, 2009 11:43 pm

No problem. As someone already suggested, check the ground first, then move to the relay.

Post by **Legacy777** » Fri Jul 24, 2009 6:53 pm

N1446 wrote:ok the pump runs off direct 12v
when everything is connected in the car it will not turn on in the ON position even though there is voltage present - approximately 10v
the car is meant to presurize the line when its in "ON" correct ?
-
is there a relay or fuse that is connected to the ignition that maybe be the cause ? : i m sure the grounds are correct as they have not changed and there IS voltage to the pump whne turned "ON"

Test the pump voltage with the key in the "START" position ONLY! If you have not done that, do that first before messing with the relay. It very well may be the relay, but I'd highly suggest checking voltage with the key in the "START" position and engine cranking.

log1call · Post by **log1call** » Fri Jul 24, 2009 10:22 pm

The relay can be powered from the test connector under the dash for testing purposes.
That checks the relay, the wiring and the power supply to the relay all at the same time.

Post by **Legacy777** » Mon Jul 27, 2009 6:34 pm

log1call wrote:The relay can be powered from the test connector under the dash for testing purposes.
That checks the relay, the wiring and the power supply to the relay all at the same time.

Very true. Connect the green connectors, and the relays will cycle.

N1446 · Post by **N1446** » Mon Jul 27, 2009 7:40 pm

Ok Great

- today i picked up another relay from the 93 LS i sent to the boneyard a while back
- I also found your post Josh on switching the fuel sender for one thats larger - i take it the location for the pump ground you chose works fine - the pics are right on , i m getting after it later today

appreciate it

Post by **Legacy777** » Tue Jul 28, 2009 3:55 am

Which post did you find. I ended up putting the ground back to the original wiring, but just bypassed the stock connector.

I ended up going back and checked the resistance to the battery from the stock ground wire vs. the chassis ground. The chassis ground had more resistance, so I put it back to the stock ground wire.

N1446 · Post by **N1446** » Sat Aug 08, 2009 2:57 pm

i found the picture where you moved the ground up high on the seat back
-
As it turns out the relay is not the issue , the R22 connection is the RFO
i picked one from a RHD postal wagon

and spliced it in place of the original
-
when the key turns to on it gurgles for two seconds
when the key is in 3/4 start the pump runs fully until i hit the ignitor
-
here are the nastty pics of the crud and burning of the crappy connector
and of course of the new one for comparrison
-
FYI
the total number of subarus in the local boneyard is now four , including the 93LS i donated in April - and the one i pulled the EJ25 from - I find it amusing that the yard is filled with GM

Thankx again

for the replies

Post by **Legacy777** » Sun Aug 09, 2009 10:15 pm

That's a much nicer looking connector!

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fuel pump & voltage troubleshooting

fuel pump & voltage troubleshooting