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Ea81 Fuel Pump Troubles


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19 replies to this topic

#1 Skylar

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Posted 05 June 2014 - 10:59 PM

Just got the 86 hatchback I picked up to move under its own finally. Take it around the block & it chokes an dies. Was low on fuel so i put 2 gallons in & go to crank it & i notice the fuel pump isn't priming. Unplug the connections @ the pump & the relay still getting no start. Its got a brand spanking new pump in it as well from the previous owner ( Monstaru )

I don't have a multi meter handy so i can't check to see if it pushing the right amount of power.

Checked all my fuses as well & none are blown. Everything's grounded etc. Possibly just a relay that decided to go bad at the wrong time?
Kx

#2 Nate E.

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Posted 07 June 2014 - 10:23 PM

I have an '83 GL EA81 that was giving me fits in the fuel pump zone. After much reading on USMB, I figured it may the grounding of the pump. Factory-wise it is grounded back through the computer. But that can become questionable after a few decades. I soldered in a ground jumper, running to a mounting screw. Ring terminal at the screw end. No problems since. I thought the filters kept clogging up & the pump was becoming intermittent. But no, just a janky ground. Mind you, the 12V to the pump only happens for a couple seconds when the key is turned on. Just primes the situation, then waits for a signal from the distributor that the engine is indeed turning. More a safety thing I guess.

All this is predicated on the assumption that an '83 EA81 has a similar system to the '86 EA81, aka; digital carb :blink: .

 

NE


Edited by Nate E., 07 June 2014 - 10:28 PM.


#3 Skylar

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Posted 08 June 2014 - 09:52 AM

Thanks for the reply ... I also found that mine had to do with a ground. Roommate of mine accidentally put one of my.body grounds onto the negative side of the coil when helping put it back together after a clutch job recently.

Grounded it back to the body, turned the key over, fuel pump primed for a few seconds then went quiet like normal. Still no start. Found out I am now blowing Ignition/Coil fuses everytime I put one in...

I'm thinking my coil wires are backwards or something now but I've swapped em around & its still blowing fuses ...

#4 Skylar

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Posted 08 June 2014 - 06:54 PM

Here's a few pics to help with the situation. Now every time I ground that wire & turn the key over its not priming the pump like it was before, still blows Ignition fuses when grounded though....

Here's my coil, 1 yellow wire from disty to + side. The black to - obviously. Then I have another yellow coming out of the harness that goes to + side & another black w/ white stripe wire that comes from the little cylinder thing mounted to the coil bracket that goes to the - side of coil I believe.
IMG_20140608_164042_zpsx2lghwr2.jpg

Here's the ground wire causing my issues.. it comes out of the harness I believe it was a body ground.
IMG_20140608_164059_zpsxarqffgs.jpg

And the right side wire coming from the thing mounted to the coil bracket going to the ground/mount on the air filter housing
IMG_20140608_164518_zpsz7gpjexc.jpg

Believe the little cylinder thing I'm.referring to might be the ignition module?

There's also a red wire tapped into my fuel pump plug that runs all the way under the car up into the rubber grommet by the drivers side firewall & down into the kick panel where its tied into a green wire that goes to one of the main white plugs under the dash ... thinking someone wired it for key on power?

#5 Skylar

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Posted 08 June 2014 - 08:26 PM

Any of you electrical/Ea81 gurus out there have an idea as to why this black wire keeps blowing my fuses? I swapped the yellow & black wires around & it made the fuel pump prime but every time i ground that wire it blows a fuse!

#6 rrgrr

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Posted 08 June 2014 - 09:11 PM

I've not seen any wires on the air cleaner bracket on any ea81 I have owned. I tried one of those Accel coils and had lousy luck with it -Plenty of power, just a really poor fit in the bracket, the coil wire boot wouldn't stay on either. That's my .02, fwiw, hth



#7 turbosubarubrat

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Posted 09 June 2014 - 12:30 AM

The little cylinder with 2 wires is a condenser and the ignition module is in the distributor. If you haven't plugged in the carb harness that will help it run better when you get it going. If it is plugged in unplug it. I had a problem on my hatch were the coil was blowing fuses and i couldn't find the short like you. So i put in a crappy harbor freight fuse and let it do its magic and fry a wire going to the carb. This actually happened on accident but helped solve my problem even thought the plastic on the fuse melted off while the aluminum was still intact. The wire lead to a senor on the carb which i replaced and it started up fine with out blowing a fuse afterwards.



#8 Skylar

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Posted 21 June 2014 - 09:31 PM

I have an '83 GL EA81 that was giving me fits in the fuel pump zone. After much reading on USMB, I figured it may the grounding of the pump. Factory-wise it is grounded back through the computer. But that can become questionable after a few decades. I soldered in a ground jumper, running to a mounting screw. Ring terminal at the screw end. No problems since. I thought the filters kept clogging up & the pump was becoming intermittent. But no, just a janky ground. Mind you, the 12V to the pump only happens for a couple seconds when the key is turned on. Just primes the situation, then waits for a signal from the distributor that the engine is indeed turning. More a safety thing I guess.

All this is predicated on the assumption that an '83 EA81 has a similar system to the '86 EA81, aka; digital carb :blink: .

 

NE

 

Did you run a ground wire from the pump or the computer ? and did you just ground it to the body somewhere ? 

 

i got the car running, but it will only run with the wire that someone rigged from the + side of the pump to a connector under the dash with key on power. Pump comes on when key is in ACC position & it shouldnt. Also does not shut off after car has started. Continues to make priming noise .. Obviously not safe to run a pump thats on at all times, in case i crash, roll over wheeling etc...

 

did some research & found that the yellow wire on the FPCU plug is for the tach signal & it was getting 0.58 on the meter. bad tach ground not giving power to pump ? ive got a couple FPCU units but dont believe thats the issue. 



#9 TomRhere

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Posted 22 June 2014 - 06:14 AM

The Black wire attached to the air filter is a ground wire.

I would move it to a more favorable spot.

 

The Black/White wire is an ignition "Hot" wire. Reason you blow the fuse when it's grounded.

Can't say what it should be attached to, but definitely not the body.



#10 Skylar

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Posted 22 June 2014 - 10:15 AM

The Black wire attached to the air filter is a ground wire.
I would move it to a more favorable spot.
 
The Black/White wire is an ignition "Hot" wire. Reason you blow the fuse when it's grounded.
Can't say what it should be attached to, but definitely not the body.


Thanks for the response. Ive got all that figured out. Now what im trying to figure out is why my pump turns on when the key is in the Acc position. Then after I crank it over, you can hear the pump continue to run, no bueno. It should prime for a couple seconds then go quiet.

Pump is brand new, swapped out fpcu, I believe im not getting a signal from the yellow wire that is a part of the fpcu plug harness & controls the tach & gives the fuel pump the signal to turn on when cranking ...

Any ideas ? Do I need to trace that yellow wire back to the tach on the gauge cluster & see if its got a poor ground ? Id rather not tear into the dash but if I must ...

#11 TomRhere

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Posted 23 June 2014 - 10:31 AM

Ok. Was out in the garage, un-buried my '82 BRAT to look at it's wiring.

 

The Black/White wire from the harness goes to coil +, along with the Black/White disty wire. (That is the loose wire coming from your harness.)

The Yellow harness wire goes to coil -, along with the Yellow disty wire. The condenser wire also goes there.



#12 jono

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Posted 23 June 2014 - 05:25 PM

yeah, was just coming in to say I associate yellow wire with negative on Subaru coils, and tacho comes of other side ?  I think



#13 Skylar

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Posted 25 June 2014 - 12:47 AM

You're kidding me. So I've been driving this car for the past few days with the coil wires backwards? Is that even possible? if it wasn't sitting in a value village parking lot right now due to my steering extension failure I'd go have a look at it but I pretty sure all my yellows on are the + side & all my black/white wires are on the-

#14 TomRhere

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Posted 25 June 2014 - 03:03 AM

They will run with coil wired backwards, just not as well as they should.

 

Going by the pic of the coil, I only see the disty's Black/White wire on the coil, along with the condenser lead. 

Is another B/W wire attached that's not visible in that pic angle?



#15 rdweninger

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Posted 25 June 2014 - 11:18 AM

TomRhere,  my notes indicate same... with exception of the condenser.... which notes say goes to the positive side of coil.

I'll get a visual on my Hatch tonight and report back tomorrow.    The yellow from the harness is the tach signal wire.  Beings that was hooked to the same side as B/W from harness which is 12v ignition... the fuel pump ran constant with key on.



#16 Skylar

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Posted 25 June 2014 - 07:40 PM

Ok, so I switched the wires around. Black/white wire from harness & disty to + side. Yellow from harness, disty, & black wire w/ yellow ring terminal on it from left side of ignition condenser all to - side.

Still not priming the fuel pump as normal & runs the same. Has a sputter/surge in all the gears. New ngk plugs & wires. Cap rotor are new. Timing is dead on.

Ill do some more tinkering on it now that it's home. Figured I'd post an update

#17 Skylar

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Posted 25 June 2014 - 08:30 PM

Just had ny roommate cranking over while I checked the voltage at the pump. Getting around 10.5v while cranking, not horrible but it's not 12v.

I unplugged the wire that was rigged to make the pump run with key on power, pump doesn't prime when I turn the key over but after it starts the pump turns on & I can hear/Smell it while it's running ..

I'm stumped lol

#18 Skylar

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Posted 27 June 2014 - 08:53 PM

Any idea why the fuel pump would come on & stay on after the car starts but not prime then go quiet when the key turns to the ON position?

#19 TomRhere

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Posted 28 June 2014 - 06:32 AM

I am not convinced that the carb ones do the 'key on prime" like the FI ones do.

 

Owned 4 BRATs and never heard the pump prime in them when I turned the key to "on".

 

There is enough fuel in the float bowl to start the engine.



#20 Skylar

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Posted 28 June 2014 - 01:51 PM

Now that you mention that I don't recall my last hatchbacks fuel pump priming or coming on with key on power either. This is my 2nd ea81 vehicle. Only owned spfi wagons before.

I wonder why I can hear this one come on & stay on after it starts. Beats me.. ha.




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