What tells the fuel pump to pump?????

TheSubaruJunkie · Post by **TheSubaruJunkie** » Mon Aug 04, 2008 2:57 pm

My car died last night. Left me stranded 75miles from home.

I pull the fuel line leading to the filter, crank the motor, nothing comes out....

What tells the pump to start pumping?? Is it the ECU? Does it use the crank angle or cam sensor? I pulled codes and im getting 11, 23, 49... there is one other, it was 2am on the side of the road so the codes could be wrong. I'll check again tonight for the codes... i know there were four.

Not sure where to check first.

93forestpearl · Post by **93forestpearl** » Mon Aug 04, 2008 4:25 pm

It should prime for a couple seconds when you turn the ignition to the on position. If that's not happening, your main relay could be at fault. This happened to a friend of mine. If that relay is bad, you'd also have to power to your injectors or ignition coil.

The main relay is in the upper left corner of the dash. The only way I know to get at it is to remove the dash somewhat. You don't have to completely remove it from the car, but it needs to be loose enough to pull away several inches.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Tue Aug 05, 2008 12:47 am

The car ran on brake cleaner for a few seconds. So im positive there is spark.

Im going to go home after work with my multimeter and start testing some things. Im also going to hard wire the pump and see if i can get it to kick on.

Matt Monson · Post by **Matt Monson** » Tue Aug 05, 2008 2:32 am

The ECU tells the fuel pump to pump. It then sends a signal to the fuel pump relay, which is right next to the main relay, which turns it on. It turns on in the accessory position before you ever crank the car and try to turn it over.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Tue Aug 05, 2008 3:10 am

I put the car into d-check mode and tested for voltage at the pump. It cycles 12v, so i know the pump should be getting juice. When I plug the pump back in, it does nothing.

I tapped on it with my ratchet and it came to life for a split second then stopped. Only did that twice then it did nothing.

Guess tomorrow im getting a new fuel pump

Matt Monson · Post by **Matt Monson** » Tue Aug 05, 2008 3:19 am

An $85 Walbro works just as well as the $2-hundred and something stocker.

I've got some used JDM pumps if you want to give one of them a shot. PM me if you are interested.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Tue Aug 05, 2008 3:25 am

Where can I get a $85 walbro pump? Is there a napa part number?

I need one tomorrow. Or else I would PM you. Even at my cost, an OEM replacement from Napa is $130 to $200.

Are these specific to the Turbo?

Matt Monson · Post by **Matt Monson** » Tue Aug 05, 2008 4:13 am

Yes,
They are specific to the turbo. The turbo pump flows more.

My local Subaru dealership stocks the Walbros, as do several speed shops in the area. It's a pretty common upgrade. Any shop supporting "stage 2.5" or above for the WRX will have the pump.

555BCTurbo · Post by **555BCTurbo** » Tue Aug 05, 2008 5:01 am

I was gonna say little fairies make your fuel pump turn on...but it appears I am wrong...

Now...enough of the silliness...

If you are interested, I have a working used turbo fuel pump I could part with for pretty damned cheap

joshm · Post by **joshm** » Tue Aug 05, 2008 8:20 am

I have my stock turbo pump in good shape that you can have for $25 plus shipping ?

If you want to see if its your pump, pull off the access panel, then pull out the pump. Itll take you 20 mins. Grab a batter charger, and hook the positive and negative clamps to seperate nails (yea the kind you hammer into walls). The pump will have a positive and negative side, touch the pos nail to one, neg nail to another and plug in the charger and see wat happens.

Matt Monson · Post by **Matt Monson** » Tue Aug 05, 2008 2:46 pm

joshm,
Did you even read the thread?

TheSubaruJunkie · Post by **TheSubaruJunkie** » Tue Aug 05, 2008 3:23 pm

joshm wrote:I have my stock turbo pump in good shape that you can have for $25 plus shipping ?

If you want to see if its your pump, pull off the access panel, then pull out the pump. Itll take you 20 mins. Grab a batter charger, and hook the positive and negative clamps to seperate nails (yea the kind you hammer into walls). The pump will have a positive and negative side, touch the pos nail to one, neg nail to another and plug in the charger and see wat happens.

Or I could just use the proper tools. Probe 12v from the battery and feed it directly to the pump while its installed.

or better yet, I could test the harness for 12v signal and verify wether or not the pump is working. I think i'll do that instead of sticking nails into my fuel pump.

If I call the dealership and ask for this Walbros pump... is there a part number I can refference?? or do I just ask for a Walbro pump for a Legacy Turbo 2.2???

93forestpearl · Post by **93forestpearl** » Tue Aug 05, 2008 4:16 pm

Matt Monson wrote:The ECU tells the fuel pump to pump. It then sends a signal to the fuel pump relay, which is right next to the main relay, which turns it on. It turns on in the accessory position before you ever crank the car and try to turn it over.

Oops, that's right. There is a separate realy for hte fuel pump, next to the main relay. Its been a while since I've messed with my wiring.

Post by **Legacy777** » Tue Aug 05, 2008 5:33 pm

Pump: GSS341
WRX fuel pump conv kit: 400-791

I highly recommend getting the kit. It makes everything a truly plug and play operation.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Tue Aug 05, 2008 5:59 pm

$104 from Napa, im just going to get it from there cause they will deliver to my work and i can run home and slap it in.

ultrasonic · Post by **ultrasonic** » Wed Aug 06, 2008 3:25 am

Also check the fuel pump wiring harness connection under the rear seat on the passenger side. The connector can corrode, causing extra resistance, which then draws more current. The wiring is marginally spec'd in the first place and the extra current being drawn through it makes it worse. The signs to look for are brown/black discolored connector, and browned crispy wire.

Do a search to find more specifics.

joshm · Post by **joshm** » Fri Aug 08, 2008 1:33 am

TheSubaruJunkie wrote: Or I could just use the proper tools. Probe 12v from the battery and feed it directly to the pump while its installed.

Do what ya want, just an easy suggestion. I hate paying to overpriced sh*t from the dealership when i can do it myself for free

555BCTurbo · Post by **555BCTurbo** » Fri Aug 08, 2008 4:42 am

joshm wrote:
I hate paying to overpriced sh*t from the dealership when i can do it myself really ghetto for free

Dynamic Entry · Post by **Dynamic Entry** » Fri Aug 08, 2008 6:50 am

555BCTurbo wrote:I turn into a bat at night and use my hella cool sonar to navigate yo

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What tells the fuel pump to pump?????

What tells the fuel pump to pump?????