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Fuel Pump Problems


markjw
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I'm trying to make this 1993 Loyale run. I got it free with lots of timing components missing. And,the oil pump was off.

 

Anyway,I have it all back together. If fuel is the intake,it starts. In fact,I bypased the fuel pump electrical system,put 12V directly to the pump and it runs pretty good.

 

Initally,I could hear the pump cycle for a second or so when I turned on the ignition with the key. That ain't happening anymore. The pump is silent.

Except,of course,when I put 12V to it.

 

The fuse in the block that is marked Ign.Fuel is good. And,I have 12V of power in that slot when I put a Volt meter on the two tabs.

 

I'm going to replace the fuel pump relay tomorrow with one I get from the yard.

 

Any other advice on what I might check?

 

What about the white plug that plugs into the back of the Alt.?

I know its related to the pump,but if I have 12V at the fuse,can I rule that out as a potential problem?

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Have you checked your codes Mark? right under the steering wheel it will flash and it should give you an Idea what is going on........it just a thought, could be far deeper than that but its worth a try......................:)

 

Jeff

 

I never even thought of it,Jeff.:rolleyes:

 

I have been messing with the ea81 cars for so long,I kinda forgot about that.

 

I'll do some research on it and check it out. Thanks,Man.

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See if voltage is getting to both sides of the pump leads when you turn the key ON with the meter reference lead tied to ground. If you have voltage on both leads then the ground side of the fuel pump circuit is most likely controlled by the ECU and that may have a problem.

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There is a fuel pump relay on the SPFI - the ECU controls the ground for the relay. Check for +12v to both the coil and the contacts on the relay with the ignition ON. Then check for ground - you should have ground at all times on the contact side of the relay, but only have ground when the ECU tells the fuel pump to run (for a second at key-on, while cranking, and cycling on/off with the green diag. plugs connected) on the coil side of the relay. The relay's pin-out is written on the side of the relay itself.

 

GD

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I beleive that is the case. From my experience swapping SPFI over to the EA81 I know there are two 12v leads to the FP relay, one ECU controlled ground for the relay coil, and a 12v output to the pump. So on one side of the relay contacts you should be able to take a resistance reading through the pump to ground. The pump is grounded but I'm not sure if it's grounded near the pump or through the harness to one of the engine bay ground points. Probably the latter from what I know of Subaru harnesses in general.

 

GD

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Thanks for all the Great advice. In the end,I think it was corroded wires or spades. After pulling the relay out and unpluging and replugging a couple connections,the pump started working again. So,this wagon is shaping up. I have to do a little cleaning,but its straight and the paint is good. I'm thinking about staying with the Northwest Green color. But my wife and kids are really complaining. I may in the end have to go back to the burgandy/red.

 

greensubi1.jpg

greensubi4.jpg

greensubi2.jpg

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