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Car has no fuel - 12 volts at pump harness


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Hello everyone! A little searching did not seem to pull up this particular piece of info I'm looking for.

 

1999 legacy outback died on the interstate. I charged the battery and it will turn but wont start.

 

I had a friend turn the key to "on" and found 12 volts at the fuel pump harness for a moment. High likelihood it's the pump right?

 

Thanks y'all.

Edited by bluegreene
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You should get 12V for 1-2 seconds when the key goes from acc to run, that is the ECU hitting the fuel pump relay to power the pump to prime it. It should also get 12V in crank (or when engine is running).

 

You could potentially use some jumpers to apply 12V to the pump to see if it is working, just to rule out any other possible wiring issues.

 

But...if you haven't checked fuel pressure while cranking, etc....and you are just thinking, car died, maybe fuel pump is bad....

 

it would be far far more likely to be that your timing belt snapped or jumped teeth.

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Things more likely:

Timing belt

Fuel pressure regulator

Fuel Pump relay (rare but it happens)

 

This is a rare failure on a subaru but it does happen.

 

How many miles on it

When (it is when yes?) was the timing belt changed and what parts were also done at the same time.

 

And as above says, you really need a fuel pressure test

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The pump harness? You mean right at the pump under the trunk? Have you tested for pressure under the hood? Dunno if these cars have a pressure relief valve, but if not, unhook a fuel line and see what happens.

 

Can also always try running jumper wires directly to fuel pump.

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There is a pressure regulator on the fuel rail, a back pressure regulator really, goes about 34psig to 44psig or so, adjusts it against manifold vacuum to keep the differential pressure between the intake and fuel injectors roughly constant. The pump also has an internal pressure relief around 65psig or so.

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I vote timing belt.

 

They fail MUCH more often than the fuel pump.

 

And or course and more expensive and involved to fix.

 

So miles and routine maintenance info (like timing belt & idlers) would help.

 

I too am thinking you're looking in the wrong end of the car.

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Things more likely:

Timing belt

Fuel pressure regulator

Fuel Pump relay (rare but it happens)

 

This is a rare failure on a subaru but it does happen.

 

How many miles on it

When (it is when yes?) was the timing belt changed and what parts were also done at the same time.

 

And as above says, you really need a fuel pressure test

 

Hmmm...maybe try squirting some EtherStart type stuff in the intake and see if it fires at all. If not, then it could be a timing belt or igniter or crank angle sensor or.........

 

 

CEL on? what codes are stored?

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This thing is actually not my car. I'm just helping out a friend.

 

It's at 110K. (I really pray he had the timing belt changed.... :-\) I sent him an email requesting maintenance history. I don't know anything about past maintenance. Supposedly, the girl who was driving it when it broke down said there wasn't any crazy noises.

 

So, I don't have a pressure tester. Would a car parts place have one for me to borrow?

 

I'm almost wishing the pump was on the bottom so I could just unhook the hose and turn the key on and let the fuel run onto the driveway for a second.

 

Thanks a bunch guys. :headbang:

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How timing belts/chains fail, this is typical but not always.

 

When the engine is suddenly unloaded, like shutting off the engine, or taking your foot off the gas pedal, lest say, like on a highway. They are great at pulling but usually they are stretched out. The sudden unloading causes slack and the belt jumps, sometimes taking a tooth or three with it.

 

Usually one tooth the car will run like crap and you escaped the big one. Car not running, well....

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It's going to need a rebuilt motor isn't it.... Assuming it's the timing belt.

 

Funny, I've been planning on capitalizing on poor maintenance by picking up an outback with a busted motor and putting a new engine in it.... Didn't think I may be getting that chance from a friend.... But it's an automatic so really, I have no interest.

Edited by bluegreene
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