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Fuel pump problem


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My first post, just found this forum.

I have a 92 Sub Loyale wagon that has a problem that nobody can seem to cure so I'm turning here for help.

95 % of the time, it starts just fine, BUT for some reason it will sometimes not start due to the fuel pump not activiting. After it sits for a few hours, it'll start just fine. When it doesn't start I can't hear the fuel pump. After sitting for awhile, I turn the key on and I hear the fuel pump pumping and it starts and runs just fine.

I've had the car for several years but this just started a few months ago and I've taken it to several mechanics and they just scratch their heads.

On a side note, the "check engine" light will come on after a mile or so, sometimes it glows steady and sometimes it flashes.

It has about 133,000 on the clock, carries great oil pressure, runs great AFTER I get it running.

I would appreciate any help that any of you can give me.

Thanks

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Sorry, I can't help you, '92 is a bit to new for me.

 

Just wanted to welcome you to the board.

 

I'm sure one of the Subaru Guru's will be here shortly to give you some directions on this. Lots of good people here, and some good info is to be found.

 

Would suggest doing a search for fuel pump related threads, as this is something we all suffer from at one time or another. The search function is at the top right hand side of the pages, just incase you may have missed it.

 

Again, Welcome to the Board.

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I really appreciate the quick responses.

I have checked the fuel pump by direct wiring it and it worked fine. I bought a Chilton book on it and inspite of reading it several times, I still can't find the relay. I found two relays under the hood passenger side. Both the same so I swapped them, no difference. It's driving me nutter than it already has.

Thanks.

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Hmm? The only thing I've seen with the F.P. wired through the oil pressure switch is GM's. And I don't think the Loyals will kill the pump if the Alt isn't charging, I think that ended with the old GL/DL's. The fuel pump realy should be near the computer under the steering colume, I think its the round relay but I can't be sure right now.

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I have gotten under the dash several times and I can only find one relay and according to the Chiltons, there should be two there. As I said, it is driving me nuts, may drive me back to drinking. <G>

Thanks folks. I may try running a wire direct from the coil to the pump, bypassing that @$$%$# computer. As you might have guessed, I HATE computers, probably because I play (?) with them everyday. Is there a cable available to interface with my laptop that will tell me EXACTLY what is wrong???

Thanks again

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The fuel pump relay and the ignition relay are directly above the ECU. Loosen the 3 nuts that hold the ECU. Its not necessary to remove them. Then drop the ECU down . Right above the left hand side of the ECU is where they will be located. If you aren't sure what the look like, I will take a pic of one tomorrow and post it.

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some subes dont use a relay for the fuel pump.

92 loyale does though. it powers up both the fuel pump and the coil acording to my diagram. wiring off the coil will not help if the problem is on that circuit. it would however make trouble shooting a bit easyer. check for power at the coil + when it wont start. this could be the relay or the driver in the ecm. this has been a problem on some subes.

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calebz, thanks for that info and no, I don't know what one looks like and would like a pic of one.

rallyruss, I'm not sure where it powers from but it does try to start when the fuel pump is not working. I can use ether and get it to run. I thought about holding a plug wire when trying to start it but that might be too shocking. <G> Not to mention that my arms are not long enough.

GoldDiggerRoo, I already have a theft prevention switch that won't let the starter work when activated but it is a good idea.

Thanks for all of the good ideas and help.

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rallyruss, I'm not sure where it powers from but it does try to start when the fuel pump is not working. I can use ether and get it to run.

 

ok I dont quiet get what you are saying here.

 

the ecm turns on the relay, the relay gets its power from the fuse, the relay turns on the coil and the fuel pump.

 

so if this were the problem it would not try to start at all. I think we are barking up th wrong tree.

 

it could be as simple as a bad fuel pump.

sometimes when pumps get a bad spot on the armature the will intermitantly not run. or a crappy connection could do this too. the FP wiring goes up under the rear seat, along the right side of the car up under the dash at the right kick pannel.

 

trust me I have been in your shoes before.

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rallyruss, I think that you have given me the idea that I need.

As I said, when it doesn't start because the FP isn't pumping, I can run a hot wire to the pump and it runs so that kind of rules out the pump being bac or having a bad spot because even after I run it with the hot wire, it still won't pump until it gets good and ready.

I've checked the fuses in the kick panel, drivers side, and these are all good. That kind of narrows it down to the relay or a fuse that I can't find or (God forbid) the ECU. Do you think that I am right in my thinking?

Thanks

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That is what I'm thinking. Tomorrow I will disassemble the car until I find that relay. Hopefully, the nice guy that said he would post a pic will do so, that way I will know what I am looking for.

I will keep everyone posted on my progress and cure.

Thanks again

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celebz

Thanks for the pic, now I know what I am looking for.

Priced one at the dealer this morning and about had another heart attack, $44+. Do you have any idea where I might find one cheaper????

Now I have to go out and find the relay see if MAYBE the contacts are dirty.

I'll let you know if I find it and if I can fix it.

Thanks to everyon

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Just an update, I found a relay locally and put it in just now. Seems to work better but only time will tell.

When I first went out to work on it, it started just fine but the other day it started for about 10 seconds and then died, hadn't tried again until today.

That relay was a bugger to get to, shed some blood. Those engineers need to work on their cars after they design them. I'd bet that they would design them to be easier to work on.

I thank all of you for your help, I couldn't have done it without you help.

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I also welcome you to the board Oldeman.

 

Your cars wiring should have some colored plugs near the ECU that you can use to troubleshoot with. They may be green and also black. When you plug one of the sets together it will do certain test proceeds. Your ECU may also have a LED you can read the stored codes from. Your manual should cover the operation of the way the proceedures work.

 

One thing that can happen to kill the FP operation is if you loose the CAS signal. If the ECU or FP control box (depending on the model) does not see that signal it will turn power off to the pump. Hopefully you will have no more problems now that the relay has been changed out. You can also swap relays if they are the same color, to do some future testing.

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