What controls the flow of gas to the cylinders?

[Oberonian]

I have a four cylinder Outback wagon (2000) that is not getting fuel to the cylinders.  I have check the fuel pump by removing the supply hose at the filter in the engine compartment.  There is good flow, however the engine will not kick over unless I spray fuel into the intake manifold. When I do this the engine will start briefly then sputter to a stop. My question is how are the fuel injectors controlled?  Any insight to this problem would be appreciated.  Much thanks in advance.

 

[987687]

If the engine in running when you put fuel into the intake manifold, it's likely you're getting spark. The injectors are fired by the computer.  I would suggest using a noid light or oscilloscope to check the pulse to the injector plugs, make sure the computer is firing them. It's somewhat unlikely that's your problem, though. If it just stopped all of a sudden it's probably the fuel pump. There's a metal cap thingy in the fuel pump assembly that blows out on those causing a loss of fuel pressure. With no restriction on the fuel line you'll get good flow, however with a restriction it isn't going to build enough pressure to fire the injectors. The first step in diagnosing this would be to check your fuel system pressure, it should be somewhere around 40psi.

[1 Lucky Texan]

have any repairs, maintenance or wrecks happened just before this began?

 

is there a check engine light? post the failure codes.

 

when was the timing belt system last serviced?

[Oberonian]

As far as previous problems with the Subaru. I had the throttle position sensor replaced by a mechanic because the car was bucking. the failure code was 1057, but the replace part t did not entirely resolve the problem.  Three weeks later the car failed completely and it is now a retirement hobby.  The timing belt was replaced about 30,000 miles ago.

 

It seems logical that low pressure at the injectors would restrict enough fuel from getting into the cylinders and prevent the engine from turning over. How do you measure what the actual pressure is? It has also been suggested that there could be a problem with the cam position sensor, that when defective, can turn off the firing of the fuel injectors. Is this correct?

 

The Noid light sounds like a great idea!!  I've looked them up online at Habor Freight and their test kit is suitable for testing GM TBI, GM SCPI, GM PFI, GM MULTEC2, BOSCH2, FORD TBI, GEO TBI and BOSCH PFI systems.  What system does the Subaru use?  Could you recommend a reasonably priced noid light?

[DaveT]

To test fuel pressure, get a t fitting and a fuel pressure test gauge. Connect after any filter in the injector supply line.

[1 Lucky Texan]

even seeing some fuel flow, may not mean pressure or volume is adequate. Our cars have a cap/o-ring on the fuel pump that may be ruptured - starving the car of fuel.

 

read here; http://www.subaruoutback.org/forums/110-gen-2-2000-2004/41182-symptoms-fuel-pump-o-ring-problem.html

[987687]

I'd connect the pressure gauge with a T between the under hood fuel filter and the intake manifold.

 

Not sure which noid light would be best, I just plug in an oscilloscope.... Check the fuel pressure first, though. That's more likely the problem.

[Fairtax4me]

+1 n what Texan said. Common issue, and would cause your initial problem as well as the current no start problem.

[desertsubaru]

When you say you disconnected the fuel line at the filter was it the line going into the filter or the one coming out. Could just be a really clogged filter.