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Howto: Fuel pump relay & 88 DL SPFI


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Ok, I finally got my car running again. I couldn't find a single zerking thread that actually gave me all the info I needed, so... I'm creating one.

 

Keywords: fuel pump relay 1988 DL wagon SPFI jumper relays horn starting

 

If the fuel pump doesn't run (no growl from the back of the car with the ignition on), it could be several things, but one cause can be the fuel pump relay.

 

The first thing you'll want to check is the voltage to the fuel pump. It's located under the passenger's side of the car, right in front of the rear tire. There will be an electrical connector going to it. Pull it out, and check for voltage (the female end is the end going to the car). You should see voltage between the terminals when the key is first turned on, and if the green diagnostic connector in the engine bay is connected the fuel pump should pulse when the key is on (but the engine off).

 

If you don't get voltage back here, another place to check is the fusebox. Fuse 11 is the one that controls the fuel pump.

 

If the fuse is good, and there's no voltage to the fuel pump, the relay is the next suspect.

 

To access the relay, you'll need to pull apart a significant portion of the underside of the dashboard. Get a good flashlight, because you'll need it.

 

Pull off the bottom access panel by removing the screws & plastic retainers holding it. Once this comes out, you'll have access to a good selection of wires. There's a bank of relays above the fusebox - this is NOT the bank you want, so ignore them (and don't randomly jumper them or you'll blow fuses, more on this later).

 

The relay you want is actually above the ECU, and there's no way to get at it without removing the ECU. So, remove the ECU. There are 3 nuts holding it on, and it has U-tabs. Loosen the nuts a bit, and then slide the ECU out. You may have to remove the frontmost connector to get it past the nut (if you don't fully remove it).

 

Now that the ECU is out of the way, you can finally get at the fuel pump relay. It's the one farther from you, and has two black/white wires, one blue/black wire, and one blue/white wire. Remove the connector. If you need the car to run, you can jumper the two thicker wires (one of the black/white wires and the blue/white wire) and get the fuel pump to run whenever the key is on. This is Bad, and Unsafe, because the fuel pump will continue to run after an accident if the engine stops. You've been warned. I consider this a limp mode to be used until the relay can be properly replaced. I'm relying on it to get me to work tomorrow, though.

 

Now, things should be working again. Reassemble everything, and the car should work.

 

However, if you've been messing around with the other relays, you may have blown the horn fuse. If your horn doesn't work, your car won't start. ECU power is apparently on the same fuse. It took me quite a while to discover this (and only after tripping across a thread on the forum about the same thing).

 

Hopefully this helps. If anyone has suggestions/additions, feel free to add them. I just want to save someone the massive amount of searching/confusion I went through to replace the fuel pump relay.

 

Also, somehow, I moved enough wires or such that my dash clock works again. No clue what I touched/reconnected, but it was all lit up when I started the car.

 

-=Russ=-

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Russ,

Let me be the first to say thanks.

 

Very well written and composed.

 

This should be used to set an example for any one wishing to post a question or an answer.

 

Thank you for taking the time to write up the documentary.

 

Maybe we can get it added to the USMB repair manual.

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Maybe we can get it added to the USMB repair manual.

 

That would be ideal. It's super easy to get an article in the USRM. Just click on the USRM link above. Click on the section you think the article belongs in. Then click the New Article button. A forum admin will review it and then post it or ask for some changes and then post it.

 

Thanks Russ !_!

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Thanks. Hopefully it helps someone else get their car fixed rapidly (instead of spending an entire evening trying to find a relay). If this is moved to the repair manual section, will it still be indexed by the search feature?

 

//EDIT: Submitted to the USRM... I didn't realize anyone could submit documents.

 

-=Russ=-

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Russ,

 

I have been through this before with another poster a while back. Was the fuse for the horn number 5? I think the same fuse supplies power to the clock also.

 

The strange thing is, my horn worked just fine until I managed to blow the fuse messing around with stuff (jumpering random relays). Or... at least, I think I blew the fuse messing around with stuff...

 

*ponders* If the ECU wasn't getting power, the fuel pump wouldn't kick on...

 

I wonder if that fuse blew and left the ECU without power. That would indeed cause a no-start and no fuel pump noise. It doesn't make sense that it would blow overnight, but I'll try to check it out when I get a chance. I'm willing to bet I blew it messing around with the relays though.

 

-=Russ=-

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Russ,

 

I am curious to find out what the fuse number was you replaced to get the horn going again. I think it is number 5, is that correct?

 

Yea, #5. HORN/HAZARDS/CLOCK

 

Thing is, the horn/hazards were working before. Just not the clock.

 

-=Russ=-

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That's what I thought the number was, thanks for confiming that. As far as the clock problem goes, I guess you are right about a loose connection between the fuse and the clock power.

Edit: I wonder if the clock not working and the fuse blowing mysteriously are related somehow?

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  • 1 month later...

Drat! I'm always a day late and dollar short. Wish I'd read this last night. I've been chasing a similar problem. At the expense of my own pride I'll explain for the benefit of my subbie brethren and sisteren.

 

My '91 Loyale has been parked in the garage for a couple of years and it's time to put her back in use. The first couple of attempts to start I got the fuel pump growl and a couple of coughs, but battery was pretty weak. I tried charging the battery and couldn't get it to start. Replaced the battery, it needed it, and tried again. This time no fuel pump growl. I disconnected the fuel pump connector, at the pump, and checked for voltage by placing my black probe on a ground and checking each wire seperately. No voltage. (Ding!) So, I started checking back up the line for a problem. Suspecting the fuel pump relay. To make a long story short, I didn't find anything. Until, I went back to the fuel pump connector and plugged my multi-meter probes into the connector at the same time. This time when I turned the key... waa laaa... voltage. So, either I didn't have a good ground the first time or you just have to make a complete curcuit to make the relay work, don't know. I pulled the pump and checked it with a 12 volt source and got nothing, until I tapped on it a few times. Now it works fine. I'll probably pump a bit of Marvel oil through it and if it works consistently put it back in. Thanks for all the info everyone gives.

 

Stretch

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No problem!

 

For reference, a new fuel pump for a fuel injected EA82 runs about $130-$150. It might not be a bad idea to keep one around for a few weeks, in case the old pump decides to crap out. They're pretty easy to change on the side of the road, but you'll want some zipties in the car to hold the pump up when you're done - the bolts holding it will most likely snap when you take them off.

 

-=Russ=-

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  • 8 years later...
  • 2 years later...

My 88 Subaru has no juice going to the fuel pump. I unhooked the computer, found the blue/black wire on #47 that goes to the fuel pump relay then to the fuel pump. I then ran a test probe from the battery to the connect wire, and then the fuel pump ran just fine. There is no signal coming out of the ECU. Fuses are intact, I checked. That was my experience.

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My 88 Subaru has no juice going to the fuel pump. I unhooked the computer, found the blue/black wire on #47 that goes to the fuel pump relay then to the fuel pump. I then ran a test probe from the battery to the connect wire, and then the fuel pump ran just fine. There is no signal coming out of the ECU. Fuses are intact, I checked. That was my experience.

 

 

In my 1988 SPFI swap my fuel pump never ran with the key flipped on.  Not even for a second.  It would run when cranking the engine or while engine is running.

 

Are you sure your distributor isn't f'd up?  If your ECU doesn't see the engine spinning *distributor signal* then it will not command the pump to turn on.

 

I don't think I have read about a single ECU failure on our SPFI cars that I can find.

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  • 1 year later...

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