52 replies to this topic

[Prwa101]

Mk ive spent days trying to trouble shoot the problem, this is was i have at the FPR (fuel pump relay)




Im not getting power the main power to the fuel pump wire, green is the ecu that grounds out and allows power to go to it. Two yellow are power only about 4-5V. never any more than that that i can think of..

I CAN get at least 3-4V at the FP power wire (no more than that) ONLY if i wire over a 12V power from the ignition Relay, to the Green FPR ECU wire.

The Two yellow wires on the FPR are hooked together LIKE the diagram shows in the wright up... but im thinking its wrong.. Im thinking the small yellow one gets 12V and dosnt hook to that big yellow one.... ????

Anyone have any ideas?? Ive been banging my head against the wall for more than 2 weeks..

Any help would be more than appreciated!!

[Subruise]

this happens alot w ej swaps. the first thing people usually say is to ground the pump to the body at the pump. hth, RV

[Prwa101]

this happens alot w ej swaps. the first thing people usually say is to ground the pump to the body at the pump. hth, RV

Hmm well i can get to pump to turn on with the old EA set up right next to this one, so are you saying it needs another ground?

EDIT: im not getting power past the FPR....

Edited by Prwa101, 10 July 2012 - 06:57 PM.

[Subruise]

yes, its differrent w a ej swap. ground your pump to the body at the pump and see what happens.

[presslab]

The EA ECU monitors the current through the fuel pump ground. This means that the fuel pump's ground wire goes back into the ECU; the EJ ECU is not like this, so you will need to complete the ground for the pump somewhere. I installed a jumper wire at the old EA ECU plug.

[Prwa101]

Mk I try that too, but I'm not getting power past the EJ fuel pump relay, no power out through the power wire to the--[]-x ------->Fuel pump. Do you guys know the volts that each wire that goes to the fuel pump relay needs? In the on position?

Oh just relized, if I wire over 12v to the ea fuel pump wire I can get it to turn on!!! So my ground at the fuel pump is good! Gosh sorry big thing that I forgot to say....
Thanks for the help guys!! love this site and the people on it!

[eulogious]

Quick question (not trying to be rude or snide here), do you fully understand how relays works? I ask because you seem to not fully understand how relays work. Read up on relays and fully understand them, and the answer will probably come to you.

Here is a good site to help you out:
http://www.bcae1.com/relays.htm

You need 12v going to one side of the relay, and ground to the other in order for the relay to work. Since this isn't a "bosch" style relay, the pins are different, but that should be explained in the EA to EJ swap write up. The EA ECU is different than the EJ, and from the sounds of it, the ECU powers (12+, not ground) the positive side of the relay, and the other side is just grounded. This is NOT the way the EA cars are setup. The relay needs 12+ volts for it to work...

[Prwa101]

Quick question (not trying to be rude or snide here), do you fully understand how relays works? I ask because you seem to not fully understand how relays work. Read up on relays and fully understand them, and the answer will probably come to you.

Here is a good site to help you out:
http://www.bcae1.com/relays.htm

You need 12v going to one side of the relay, and ground to the other in order for the relay to work. Since this isn't a "bosch" style relay, the pins are different, but that should be explained in the EA to EJ swap write up. The EA ECU is different than the EJ, and from the sounds of it, the ECU powers (12+, not ground) the positive side of the relay, and the other side is just grounded. This is NOT the way the EA cars are setup. The relay needs 12+ volts for it to work...

Hey no its not a problem! and yes i know how it works, from what you have said, both they yellow wires on the fuel pump relay need 12VV! so then the diagram in the wright up is wrong???? yeah im only getting 4V maybe 5 on they top yellow ones, which means i need to wire thouse into the yellow wires on the ignition relay? what they diagrams showd was that the yellow ones connect to the yellow and red ones... where im not getting 12V for sure.


i have it done the same as it shows in the diagram... and im not getting 12V at those yellow wires on the fuel pump relay, that are hooked to the yellow red wires...

im thinking it was a meta fore for the "rest of the harness".... Damn... sound right?

[eulogious]

From the diagram, you should have 12v going to "the rest of the harness". You are getting the 12v from the ignition relay. Once you turn the key, you power the fuel pump relay. According to the diagram. So if you are not getting 12v, then there is something up with the ignition side of things. As soon as you turn the key to "on", you should get 12v going to the fuel pump relay.

According to the diagram, you get your 12v from "the battery" and that goes into pin 6 on the ignition relay. Then once you turn the key to "on", you send 12v through pin 4 on the ignition relay, which should then give you 12v to the fuel pump relay. If you are not getting 12v to the fuel pump relay, then something is up with your ignition. I would start by going and double checking everything on the ignition side. I bet your problem lies somewhere over there...

I should also give out a disclaimer, I have NOT EVER done an EJ swap, so I am just going by what is written and my understanding of how it should work, and I have no experience in actually doing the swap, FYI.

Edited by eulogious, 11 July 2012 - 07:50 PM.

[eulogious]

Oh, and apparently I was wrong with my previous post about the grounds and the fuel pump, now that I look at the diagram, so my bad!

[Prwa101]

ahhh so the ignition relay sends out 12v through the yellow red wire in the "on" positions, BUt im not getting that 12 so somethings messed up... hmmmm yeah i have something wrong, im going to check it out!!! Why would it only send out 5v to the relay??... hmmmmm


hey no problem man! Youve said things to make my brain click on haha

[presslab]

Why would it only send out 5v to the relay??... hmmmmm

The ECU should send out "0V" (or close to it) to the relay, and the other side of the relay is at 12V to the fusebox. With electronics, they always work better switching the "ground" side of a circuit, so that's how you'll typically see things hooked up. In silicon transistors, electron mobility is about twice that of electron holes, so N-channel MOSFETs are more efficient.

Put an ammeter inline with the relay and see how much current it's drawing. I doubt the relay is the problem though, your ECU could be damaged...

[GeneralDisorder]

Sounds like you just don't have power to the right wires. You need constant 12v supply to the two yellow wires going into the ignition relay. And switched power going to the light green wire. The white/black is the ignition relay coil ground. If you have those three things and you ground the ecu control wire for the FPR then the pump will run.

GD

[Prwa101]

Okay, fixed most of if! The two yellow wires in the diagram don't get enough power from the two yellow and red wires going to the ignition relay, only 4-5v. So I wired the FPR yellow wires to the "on" position on the ignition. That fixed it! But only if I ground the green Ecu wire on the fuel pump relay, and I get my 12v at the power wire heading to the pump!

Any ideas why the Ecu isn't grounding the fuel pump relay?

Could I just leave it grounded, since I have both power wires on in the "on" position on the FPR?

And that diagram from what I'm exsperincing is wrong... :/

Thanks guys!!

[czny]

Don't know how you feel about safety but when I finally get to my ej swap on my 87 gl definitely going to add a low oil pres switch to the circuit like this:
http://www.ebay.com/...984.m1439.l2649
Voltage from the ignition switch starter wire while cranking & ignition hot thru the Hobbs switch while running. If the engine stalls & OP goes below 4 psi the FP cuts off.

[GeneralDisorder]

Okay, fixed most of if! The two yellow wires in the diagram don't get enough power from the two yellow and red wires going to the ignition relay, only 4-5v. So I wired the FPR yellow wires to the "on" position on the ignition. That fixed it! But only if I ground the green Ecu wire on the fuel pump relay, and I get my 12v at the power wire heading to the pump!

That's the wrong way to do it. The ignition relay is there for a reason. You need to find the source of the voltage drop, not remove components and wire around them.

Any ideas why the Ecu isn't grounding the fuel pump relay?

Hard to say - probably missing a ground source or power source.

Could I just leave it grounded, since I have both power wires on in the "on" position on the FPR?

No. The pump will continue to run in an accident scenario and could cause a fire or fuel spill.

And that diagram from what I'm exsperincing is wrong... :/

I've stripped more harnesses than I can count and it's never been wrong that I've seen.

Don't know how you feel about safety but when I finally get to my ej swap on my 87 gl definitely going to add a low oil pres switch to the circuit like this:
http://www.ebay.com/...984.m1439.l2649
Voltage from the ignition switch starter wire while cranking & ignition hot thru the Hobbs switch while running. If the engine stalls & OP goes below 4 psi the FP cuts off.

Completely uneccesary and a waste of valueable time and resources. The ECU already handles the fuel pump shutdown by cutting out the fuel pump relay when there is no ignition pulse (tach signal) present. The wiring, hardware, and software is already in place to support the "safety" you desire so adding additional components and wiring is just wasted effort.

GD

[czny]

"Completely uneccesary and a waste of valueable time and resources. The ECU already handles the fuel pump shutdown by cutting out the fuel pump relay when there is no ignition pulse (tach signal) present. The wiring, hardware, and software is already in place to support the "safety" you desire so adding additional components and wiring is just wasted effort.

GD"

You forgot to add the after that attack.

[Prwa101]

Hmmm well back to the drawing board... Im not getting over 5v coming from the ignition relay yellow/rd wires. But have a full 12v+ on the yellow coming from the batt. And it seems that I have 5v I think at all times in thouse yellow/rd wires... that go to the FPR power....

Good point.. Fire=bad.

Although.... This isn't a Subaru BUT, it has the same set up as I'm talking about.



Hmmmmmmm.......

[Prwa101]

I'm thinking it a power issue... Seeing as its having issues as it is, with power. Now time to trace wires....

[GeneralDisorder]

So - at the plug to the ignition relay you have 12v at the yellow wires but when the relay is energized you have 5v coming out on the yellow/red?

Bad ignition relay.

GD

[Prwa101]

So - at the plug to the ignition relay you have 12v at the yellow wires but when the relay is energized you have 5v coming out on the yellow/red?

Bad ignition relay.

GD

That would make Sence... This is what I have at the yellow and red in the off position along with in the on position....


New ignition relay it is.... :/

Thanks guys!

[GeneralDisorder]

What do you have at the yellow wires going into the ignition relay?

GD

[Prwa101]

What do you have at the yellow wires going into the ignition relay?

GD

A full 12v + coming from the igniting relay.

[GeneralDisorder]

Certainly seems like the relay is bad then. Possibly rusted/corroded inside. Cut it open and look. It's an informative experience to open a relay and see it's internals. Then it will be clear to you how that particular unit functions.

GD

[Prwa101]

Certainly seems like the relay is bad then. Possibly rusted/corroded inside. Cut it open and look. It's an informative experience to open a relay and see it's internals. Then it will be clear to you how that particular unit functions.

GD

Grrrrr.... Two things, poped open the igniting relay, sure enough the green "on" position wire on the inside little itsy bitsy wire was broke and that connection, AND I didn't have a good enough connection coming from the "on" position which made that wire go....

I HAVE IT FIXED!!! =D

Thanks GD!!! Man owe you!!