Sputtered and now won't fire - Fuel Pump?

[GTEASER]

Hey guys! My '92 SS (159k miles) died this morning. This is what happened and what I think. Look forward to some input.

So I headed off to work this morning, currently have 1/3 tank of gas, and I thought it was a little weird when the car didn't immediately fire up as it always does, first try. Second try it fired up and ran fine. I let it warm up a little and headed of down the road. Just before I hopped on the freeway I gave it about 50% throttle and it sputtered, I was surprised. Got on it a few more times thinking it was an anomalie, but every time it sputtered and stumbled really bad, falling flat on its face, but it was hitting target boost. I decided to not risk getting stranded and turned around to head home to grab the other car. I noticed that the sputter only happened when throttle input was more than, say, 30%, during cruising and relaxed acceleration the car ran fine. I put it in the driveway and turned it off, pulled the other car out of the garage and went to restart the SS to put in the garage. It turned over but would not fire.

Also, since this car is still fairly new to me (<2 months), I do drive her almost every day, and I have noticed a stumble between 3-4k rpms on initial WOT when first getting into full boost, but it runs fine the rest of the way to 6k rpms. If the fuel pump died to day, it would make sense that that stumble may be associated with the fuel pump not performing properly or reacting to the requested duty cycle quickly enough.

Obviously I didn't have the time this morning to check anything out, but I did get to thinking and it would seem that maybe the fuel pump gave up the ghost. I can check that by pulling a fuel line and turning on the ignition, right? Any other thoughts or things I should check would be welcome.

If it's the fuel pump, I will get a Walbro 255 (GSS341) with the 400-791 install kit or a DeatschWerks DW200 (9-201-0791) with install kit. Any recommendations either way? The price is comparable.

Thanks!

[SILINC3R]

when you put the key to ON position you can hear the fuel pump prime. It is very noisey. you may need to drop the rear seat forward to hear it better. And you are sure there is no leaks at the intake?

[GTEASER]

I will turn it on and listen when I get home from work. I can't ever remember noticing any fuel pump sound before but then again I never listened specifically for it.

I am pretty positive there are no intake leaks, it ran perfect under all throttle conditions yesterday. It would have had to suddenly started leaking between the time I parked it last night and this morning, plus, it idled fine and ran good in all driving conditions except for big throttle inputs, while it was actually running this morning.

[GTEASER]

So this is what I have found. Pulled the 6pin connector on the fuel tank. With key in the ON position, and per the wiring diagrams, Pins 1 (power) and 4 (ground) are the fuel pump and no voltage on either, Pins 2, 3 and 5 are the fuel level sender. Pin 3 has 4 volts (partial tank 'o gas?), Pin 2 has 12v and Pin 5 has nothing (ground).

This leads me to believe its the fuel pump relay, which sucks because it's super hard to access and buried up in the dash.

Any thoughts? Anything else that would cause the fuel pump not to get voltage when the key is ON? Given the sputtering symptoms before it completely refused to start (see first post), this doesn't make sense.

[GTEASER]

This shows the location of the fuel pump relay.

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

The ECU only powers the fuel pump relay for a couple seconds to prime the system and then stops. You can connect the green diagnostic connectors under the dash. This will cause the relays to cycle, which will allow you to check the fuel pump circuit and to test the relay.

http://main.experiencetherave.com/subar ... cuhide.jpg

The connectors should be on the left side of the steering wheel, but may be on the right side of the steering wheel.

Found this. So to actually test the relay I must plug in the green test connectors and then check the voltage at the pins on the fuel tank connector?

[Dynamic Entry]

when you put the key to ON position you can hear the fuel pump prime. It is very noisey. you may need to drop the rear seat forward to hear it better. And you are sure there is no leaks at the intake?

Listening for pump noise can be a quick way to confirm that it is working, but not being able to hear it should not be taken as confirmation that it is not working.

I cannot currently hear my fuel pump at all.

I pulled everything out of the trunk, and had my ear about 18 inches from the exposed cover plate.

Turned key ON and I couldn't hear anything.

Pulled fuel line at the fuel filter, turned key ON and fuel sprayed hard.

I have a Walbro, so maybe it is quieter than stock.

[mittens]

Very interested in this topic as my car did the exact same thing to me today. Unfortunately my car is stranded at work not home, haha.

Hoping to hear a solution soon!

[thewaterboy]

I think my pump just died as well.

[GTEASER]

Wow! So the question is.....do the green test connectors need to be connected in order to cycle the fuel pump relay to test for voltage at the fuel pump, or is simply turning the key to the on position enough to verify voltage at the pump.

I read somewhere on here that the fuel pump relay only provides voltage to the pump for a split second when the key is turned to the on position, and then constantly only after the engine is running, is this correct?

I am trying to determine whether or not my issue is with the pump or the relay without having to get to and pull the relay to test it.

[thewaterboy]

Wow! So the question is.....do the green test connectors need to be connected in order to cycle the fuel pump relay to test for voltage at the fuel pump, or is simply turning the key to the on position enough to verify voltage at the pump.

I read somewhere on here that the fuel pump relay only provides voltage to the pump for a split second when the key is turned to the on position, and then constantly only after the engine is running, is this correct?

I am trying to determine whether or not my issue is with the pump or the relay without having to get to and pull the relay to test it.

After I finish weeping, ill go outside and check. I can hear the pump prime, but I'm not convinced its working properly.

[mittens]

Is there a way to test the pump itself, not the voltage to the pump? Like partially pulling the pump out and disconnecting the feed line to the fuel rails? I would think that if the relay can't get pressure it would continue to try until it did.

Meaning if nothing happens, no attempt to prime, then the relay is bad. And if it primes, but no fuel is pumped, then its the pump. And if eveything works as it should, then its something completely different.

Is any of that logical?

Edit: checked the relay using the green plug under the dash, it works. Checked the connection under the rear seat, its in great condition. Still don't hear the pump prime in the on position.

[rallyak]

It sounds like the pump to me, my moms car eats a pump about every two years and the symptoms are: it will stumble when cruising at high speeds and try to go up a hill or pass someone. It normally gives us a days notice, stumbling and i believe it throws a code for #3 misfire. Which that's the last to get fuel, At idle or lower rpms it's normal.

[thewaterboy]

Pretty sure mine is the MAF. Its suddenly started throwing like 10 codes at once. If i unplug the maf, i can drive the car under 3k rpms and maybe 25% throttle. Any more, and it seems like fuel cut

[rallyak]

Yeah, a MAF will cause it not to start and if you unplug it the car will run, but super rich.

[mittens]

Alright guys and gals, just installed a new 255 pump and still nothing. I can hear the solenoid click under the dash, but no prime from the pump. Going to delete the connector under the seat.

What else might it be?

[GTEASER]

The relay. There are about 2 or 3 relays that click under the dash when the key turns to the on position including the ignition relay which is right next to the fuel pump relay.

[mittens]

I tested the relay using the green clips by the ecu and I clicked like mad when I turned it over. Is it possible its still not working correctly?

[GTEASER]

When you connected the test connectors and you heard clicking, did you check for 12v of voltage on pin 1 of the connector at the fuel pump? The blue with yellow stripe wire.

Pin-out with the tab up.

123
456

Pin 2 should have 12v and pin 3 could be any voltage depending on fuel level. 2 and 3 are to the fuel gauge. 4 and 5 are grounds and 6 is empty.

[mittens]

I feel like an idiot. I bypassed the connection under the rear seat and it fired up first try. I would suggest everyone do this even if the plug looks to be in good shape.

[GTEASER]

Thanks mittens, I will replace that connection with a GM MetraPak connector when I do the fuel pump. The fuel pump came Friday, and I ordered a relay too just in case, so hopefully will have some time over Thanksgiving to get her running again.

[GTEASER]

My issue was the fuel pump. I connected the green test connectors and with the key on the relays cycled. I tested and got 12v at the pump so I know the relay is good. Replaced the pump yesterday with a DeatschWerks DW200. It was plug and play and she fired right up. So at just shy of 160k, the factory original JECS pump gave up the ghost.

Thanks to everyone for the help!

[Legacy777]

Glad you guys got the fuel pump & wiring sorted out. Sorry I've been MIA to reply.

As you guys found out, yes you need to connect the green diagnostic connectors to get the relays to cycle on and off. The ECU only holds the fuel pump relay on for 1-3 seconds to prime the fuel system.

Just a note, if you bypass the factory connector for the fuel pump, I'd recommend using insulated spade connectors or some other type of connector so you can disconnect power to the fuel pump if needed.