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1988 Subaru XT fuel pump issue.(( Please Help Immediately ))


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Okay..

 

So, I have a Subaru XT.

Problem is that the starter turns, lights and electrical seem fine, and everything is in working order except the fuel pump.

The fuel pump does work and I know this because I removed it from the passenger side of the car and hooked it up to a battery charger it turns on and has small suction.

I hooked everything back up, and came across an issue where the fuel pump isn't pushing gas to the intake, much less turning on.

I checked the ground. The ECU does work.

My only question is.

Is there a way to force the pump into turning on and pushing gas to the intake.

Something like a Bypass....

 

I just got this car and I'd really appreciate some knowledgeable input....

:dead:

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Okay...

no by pass or way to force it with out hot wires

 

To wit....

 

the fuel pump only runs for 2 seconds when the ig sw is turned on.

 

It will run if the car starts.

 

It gets + battery all the time the ig sw is on

via the fuel pump relay,

it's ground is controled by the ECU

 

 

Now...

You know where it is which is good

Check to see if when the ig sw is on it has + battery

 

if not the fuel pump relay

or fuse

is toast.

 

fast enough for you??

 

Hope this helps

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Thank you for the quick response.

A side note (( The relays click but the pump doesnt get voltage and on a 12v electricians simple reader, I got .638 steady with the ignition on.))

One more question, where is the fuel pump relay?

I hear relays, but can't locate them.

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also tonot exclude this notion, has the timing belt broken? take off the disty cap and watch for the rotor to turn. the ecu needs to see a signal from the didty to turn on the fuel pump.

 

this would be the next thing to look at if the relay is determined to be good

 

both the ign and fuel pump relays should be very near the ECU, which is located in the trunk inder the rear decklid. the brown one is fuel, the green one is ign, try swapping them around and see if the ign does not turn on. if so, then your problem is the relay. if not, investigate the timing belt

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I'm not thinking it's the timing belt.

The car has just been parked for two years.

 

The owner (a close friend of mine) informed me that the car runs great.

Installed a new fuel pump, NGK wirekit and a new starter and whatever else he said...>.<

 

Even he is baffled as to why it won't start.

 

 

 

Perhaps it could be the relay...

Considering I'm new to subaru's though..

 

I need like... an exact down to the Subaru for Dumbies explanation as to where it is...>.<;

 

Sorry.. :(

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No.. we drained the tank and filled it back up.

 

 

Like I was saying though...

The Pump is getting voltage but a very small amount according to the meter. (( .638 ))

To ground the pump directly I would just run a wire off the shell of the fuel pump to the body, or the intake manifold....?

 

 

Simply have the issue of the fuel pump not pushing the gas to the intake.

 

I appreciate the input.((everyone)) :D

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Fuel Filter?

Mmm fuel pump issues with an xt.. this all too familiar to me. The first thing you need to do is test the voltage WHILE the motor is being cranked... it should be pumping 100% while cranking. If voltage is good in the 12.5 range then I would start checking the fuel sock on the "in" side of the fuel pump.. if you don't have a fuel sock your internals in the pump are probably bad now. I cleaned and cleaned and cleaned my fuel system.. eventually I had to take the tank out and pressure wash it. I had to replace all the fuel lines because of lot of them were cracking and not holding pressure. IS this an ea82 or an er27? (4 or 6 cyl?)

If voltage is bad it may be a relay or wiring issue. Try direct wiring it.. i forget which colors are +/- (one should be black(-), also i think the pump has +\- on it near the terminals) but the pump will run in reverse and it is bad for it. On my xt6 the relay are under the center console near the passenger side of the shifter.

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I forgot to mention...

It clicks once..

Then about a second later I hear a second relay click from the same spot...

Is that supposed to happen?

.....

If this is happening when you flick your key to the "on" position this is the relay turning the pump on to prime the fuel line and then clicking off so it doesn't keep turning the pump. Should be normal. open your passenger side door and see if you can hear the pump spinning.

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Have you checked to see if the engine is getting spark? The ECU needs to ignition pulses before it will turn on the pump. The fact that you are not getting at least the positive side to the pump is a concern. You need to check the fusible links and the fuses for any problem there. Then move on to the relay if they are good. The ignition relay may be in the circuit also.

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At least on the GLs, one could connect the green test connectors, turn the key to On (not start), and the fuel pump & some solenoids will click on/off at 1-second intervals.

 

You can also unplug the fuel pump and check the voltage, rather than checking it while having someone crank it over.

 

-Dave

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Just because you hear relays clicking doesn't mean they are good. Power at the pump needs to be checked while cranking.

 

+1 on checking timing belt. Pop the distributor cap off and crank it for a second while someone watches. If this is the problem, It'll drive you crazy until you confirm it.

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how do you know it's "not getting fuel to the intake?" i would like more "proof" that it's the fuel pump.

 

a "new" fuel pump was installed? what kind? OEM or aftermarket? i installed an aftermarket fuel pump in my XT6 and it did not work, i still have not figured out why. stock - fine. aftermarket with a stock pigtail wired to it - didn't work.

 

keep in mind - diagnosing and helping over the internet requires as many specific details as possible. we can't see, hear, touch or smell the thing. let us know exactly what you've done and how you know things don't work or do.

 

plug the connectors together in the trunk (i forget whether it's green or black or both of them for diagnostic mode). the diagnostic connectors should cycle the fuel pump on every two seconds as a test. see if this happens and see if any fuel spits out the fuel hose in the engine bay. you can hotwire the fuel pump but do not drive it like this unless you're really good with electronics as it's dangerous. this would be for testing purposes only, but i've done it. i also saw one like this catch on fire before as well (it was an XT even!).

 

check your fusible links, actually pull them out and inspect them for rigidity. if the battery is ever attempted to be jump started improperly you will fry a fusible link and run the risk of damaging the ECU as well.

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.

keep in mind - diagnosing and helping over the internet requires as many specific details as possible. we can't see, hear, touch or smell the thing. let us know exactly what you've done and how you know things don't work or do.

 

Well said Gary,

I wish everyone would read and heed this.

 

Not only would it make helping them easier

 

but also it would

 

help any one experiencing similar problem

possibly in the future.

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i installed an aftermarket fuel pump in my XT6 and it did not work, i still have not figured out why. stock - fine. aftermarket with a stock pigtail wired to it - didn't work.

 

Not to change the subject here but, I suspect that the polarity may have been reversed when you connected the original plug to the new pump. You may have checked that though.

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Perhaps it could be the relay...

Considering I'm new to subaru's though..

 

I need like... an exact down to the Subaru for Dumbies explanation as to where it is...>.<;

 

 

Fuel pump relay is located in the center console, below radio. Fuel pump relay is mounted atop right side of the metal bracket. It has a brown connector.

 

For reference, The Ignition relay is in the left of the same bracket, and has a black connector

 

Here is what I really want to know:

How excactly are you reading voltage? are you just probing both terminals of the Fuel pump connector?

 

Try measuring for voltage on the Blue wire and a BODY ground, other than the white wire at the connector. Use a bare metal area of the car somewhere.

 

If you still have no voltage, it i mot likely the relay, or a fusible link, or other type of short. You must test while cranking, or with the key on, green test connectors plugged in (BTW, AuxAirValv is powered on the same WIRE! you can test it and it should be the same voltage. )

 

If that shows good voltage, then I believe the problem to be in the the ECU or it's harness, not grounding the negative pump. I'm a little amazed actually that the negative connection to the pump motor is supplied completely through a shielded wire, direct from the ECU PIN 55 The numbers are stamped very small in the plastic. You may have to unplug them to verify # then plug back in

 

To conclusively test. First Open trunk and plug in the green diagnostic connectors near ECU. Turn the key on, this should make the Fuel pump cycle. You can probe the back side of pin 55(white wire), with it still plugged in, and test whether continuity to Ground is present (cycling interval in time with the ECS light)

 

 

If you have grounding happening there than you need to test the wire between. Pull the ECU plug, and the Fuel pump connector. Use long test leads on the white wire at pin 55 and the other end at the pump for continuity end to end.

 

I would also test that it is not contacting it' shielding. With both ends still unplugged, there should be no continuity to ground.

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I suspect that the polarity may have been reversed when you connected the original plug to the new pump. You may have checked that though.
i did, i verified before installing which way to wire it...and then tried both ways anyway. worked fine off the car with direct battery power. it was bizarre and no need to diagnose now.
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Okay.. So.. I fixed one issue and brought another.

I removed a custom built 15" speaker box from the backseat/trunk area.

The wires from the ecu bracket were unhooked.

I plugged the bracket back in and connected the green testers.. now the pump is getting power because I can hear the pump itself click on and off when im under the car.

The pump clicks and just gets hot.

but when hooked up to a battery charger it turns on and shows little but some suction and doesn't get hot.

I removed and swapped the relays around all of them are good.

 

Perhaps the pump actually did go out..

or it's stuck..

Any way to disassemble the pump and fix it or unfreeze it's lock.

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the green connectors are not meant to be plugged in while driving, do you know that? they are only for diagnosis, if the pump cycles on every 2 seconds that is exactly what it is supposed to do in diagnostic mode. as soon as you're done verifying that UNPLUG the green connectors, they are not meant to be plugged in.

 

have you done two simple things - make sure there's gas in it, and see if the pump will flow fuel? with the green connector connected you should get spurts of fuel every time it cycles on. 'ive done that exact test before....plug in connectors, pull the fuel line in the engine bay - if fuel comes out it's working.

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answer these questions i already asked:

 

 

how are you testing "it's getting suction"...how do you know?

 

 

I took it off the car and hooked to a 55v battery charger... hooked up two hoses and a gas can.

 

It spits out fuel .... but very slowly

Where as on the car.....

I know the green testers are for testing purposes.. but it's not spitting fuel in any way.

The pump has to be good.

I just need it to actually work.

even if I have to rewire it manually. I just need to know how to make it turn on while it's on the car.

Hooked up.. Even straight wired from the battery.

It wont spit any.

Do I need to ground the negative pole to the body of the car?

Because the relays and the ECU are.. I REPEAT.

Are Good.

and to answer an earlier question yes it's brand new.

and this is the link of the pump I have

http://www.autozone.com/selectedZip,30291/initialAction,partProductDetail/initialpartType,00078/initialR,APP171504/initialvehicleId,1083901/shopping/selectZip.htm

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