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Ea81T to carbed conv. How do i get the fuel pump...


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28 replies to this topic

#1 SuperRallyRoo

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Posted 10 March 2004 - 10:55 PM

I have swapped over my ea81T wagon to webered. And we are having problems getting the fuel pump to work. How is the fuel pump powered? Is it turned on by the disty or some other source? Could we wire it to a switch or ignition? Is the fuel pump on an ea81t switched on by the ecu? Because I removed it. (Mark I might need that back lol)

#2 samo

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Posted 11 March 2004 - 12:02 AM

Good luck with the fuel pump... wish I knew the answer.

#3 GLCraig

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Posted 11 March 2004 - 12:21 AM

Yes the Fuel pump on an EA81T is switched on by the ECU also there is a Fuel Pump Relay in the circuit.

On A Carbed EA81 the fuel pump is controled by the Fuel Pump Control Unit AKA the Rev Sensor

#4 SuperRallyRoo

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Posted 11 March 2004 - 12:23 AM

So does that mean I can wire up a switch to turn it on all the time? Or do we have to convert that small part over to ea81 carbed?

#5 GeneralDisorder

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Posted 11 March 2004 - 12:29 AM

For one thing, you can't use the stock EA81T pump for a weber without a serious pressure regulator. The turbo pump is like 40 psi, and the carbed one is 2 psi....

GD

#6 SuperRallyRoo

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Posted 11 March 2004 - 12:31 AM

Which is why we swapped over the fuel pump*.

#7 GeneralDisorder

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Posted 11 March 2004 - 12:39 AM

The fuel pump is somehow driven off the tach signal from the disty I think. There is a fuel pump control unit somewhere in the car on a carbed model that uses that signal to determine if the pump should run or not. It will shut the pump down if the engine is not turning over.... at least that's the theory. In the case of a turbo model, then I think the ECU probably does that job, as the engine was MPFI. Personally, I would find an aftermaket safety switch that runs from the tach signal, and rewire the thing.

GD

#8 Ratty2Austin

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Posted 11 March 2004 - 12:51 AM

could we wire it to the coil somehow? or does that not have the right signal?

#9 GeneralDisorder

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Posted 11 March 2004 - 12:53 AM

Wish I knew more about it. When in doubt - check the FSM wireing diagrams!

On carbed engines, I think the coil and the tach use the same signal..... since there's only two wires running from the disty.....

GD

#10 SuperRallyRoo

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Posted 11 March 2004 - 01:00 AM

So if we wire the thing up to the ignition, would that work? Or would it get too much fuel or not enough fuel into the carb?
We don't have a FSM.:(

#11 Caboobaroo

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Posted 11 March 2004 - 01:15 AM

Matt, wire it directly to your ignition so when you turn the key to "on" the fuel pump will come on. Thats the easiest and cheapest way to wire it. Then after it goes through the ignition, wire it through the relay so it'll kick the fuel pump on. I've done it before on a 1964 Mecury Comet and it worked fine.

#12 GLCraig

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Posted 11 March 2004 - 01:23 AM

I'm with GD about getting some kind of a safety cutoff switch. The last thing you want is a running fuel pump if you get into a wreck.

#13 NoahDL88

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Posted 11 March 2004 - 02:16 AM

if you hot wire it, like i'm in the process of doing myself, make sure that you have a good return line, if you don't the float bowl will overflow and you'll run so rich the car won't run, and then it really won't pass emissions cause your HC's will be through the roof

#14 SuperRallyRoo

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Posted 11 March 2004 - 08:52 PM

So I wired it up so that theres a wire coming from the hot side of the coil, to the switch. Then theres a wire going to the pump, and i have the pump grounded on the interior of the car. There is also a ground for the switch which I imagine is for the little green light in the switch. I turned the ignition to on and flipped the switch and it went UMMMMMM. The car still wouldn't start though because i think we need to wait for the fuel to slowly build back up in the line. Is this what was meant by wiring it up to the ignition? Is it going to burn my wires or melt something? Start any fires? I just want to make sure we don't screw something up badly!:) Tomorrow I will go out and buy some inline fuses and put them on the hot leads going to the switch and to the pump.

#15 GeneralDisorder

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Posted 11 March 2004 - 09:37 PM

No - it shouldn't have to build up fuel in the line.... well it should, but it's pretty fast. About 10 seconds if that. I had my Brat's engine out, and I changed both the front and rear fuel filters, and had dry lines - didn't take any time at all to fire it up with an empty float bolwl, and no fuel in the lines....

GD

#16 GLCraig

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Posted 11 March 2004 - 10:05 PM

Are you getting spark? If i've read my diagrams correctly the +13.5vDC for the coil is suppiled by the Fuel pump control unit too and so is the power for the choke heater.

#17 SuperRallyRoo

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Posted 11 March 2004 - 10:12 PM

It got spark yesterday, it fired right up yesterday when we put gas in the line. It seems like gas is still not getting into the carb. Very very interesting. Hopefully we can get it figured out today, I might not have given it enough time to fill up. We had the pump, the lines and the carb drained of gas so I imagine it might take a little longer then normal to get gas up there. Who knows...:-\
Kinda worrying me though.

#18 GLCraig

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Posted 11 March 2004 - 10:37 PM

Can you hear the pump run when you power it???

#19 SuperRallyRoo

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Posted 12 March 2004 - 12:13 AM

yes its very loud and shakes the whole car shudders even. Thats what worries me!

#20 TomRhere

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Posted 12 March 2004 - 04:28 AM

Seeing as there is a great difference in years here, I can't give you the exact wire colors to use, as they no doubt be different.

The FP on my '82 wouldn't run at all on it's stock wiring, and PO had it hot wired to a switch off the battery. I didn't like that idea, so....

I found a "key-on" hot wire under the hood, used that to power a relay. Ran hot wire from battery, thru a fuse, to the relay and then out to the FP hot feed. Works like a charm.

Didn't do it at first, but I did install a pressure switch on the oil pump. This switch closes it's contacts when it sees pressure. I then ran the ground wire for the FP relay thru this switch. No oil pressure = no FP running.

I can't find the receit for the switch, so I can't give you the number of it. I just told the counter guy what I was wanting to do, and he hooked me up with a switch.

By the way, my FP is way noisy too. Rattles something fierce. Don't know if it the original pump, or if it was swapped in when the EA-82 was swapped in. But it does it's job, so I can live with a bit of noise.

#21 Stupidru

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Posted 12 March 2004 - 10:44 AM

ea81t are so rare on EC...this conversion angers me! :confused:

#22 CIS Subaru

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Posted 12 March 2004 - 02:22 PM

Rather than mess with an oil pressure switch, I'd just get a real fuel pump relay from a junkyard car if you want a safety shutoff. I used one from a VW Rabbit in my CIS conversion. I can tell you what to look for and give you the pin-outs for it if you want.

Most carbed 4wd EA81 cars have the FP relay just in front of the drivers door near the hood release. It's a black box with a 6 terminal connector. I can give you the pin-outs for this too.

#23 SuperRallyRoo

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Posted 12 March 2004 - 03:46 PM

Stupidru- "ea81t are so rare on EC...this conversion angers me!"
Its my car man and that's not what I asked. Trust me I have gotten enough flack. I wasn't about to sell the car because its an ea81t and buy some other wagon when I had all this $ dumped into the tranny and clutch and drive shaft. Not to mention all the custom crap we have had to do. And all the time its taken! It angers me when people tell me how this angers them. I understand why your mad, but think of it this way. Who is going to want an ea81t wagon that failed emissions horribly, and every time u try to throw new parts at it, it just gets fussier and fussier?
Anyway that's my reasoning. As the car sits I have a little over $1600.00 into it. Back to the fuel pump. Thank you guys for all the advice. And sense this is my first wiring attempt ever, I am going to show it to Austin so I don't screw something up. :D

#24 SuperRallyRoo

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Posted 12 March 2004 - 06:15 PM

Ok the fuel pump was backwards, It was creating a 4psi vacuum lol. I put the pump on the right way let it pump took about 3 seconds and it fired right up. And I look around for leaks... Oil is dripping rapidly out the oil pump. Dripdripdripdrip... Also its leaking water out the heater core hose's. I'm kinda worried about this pump oozing everywhere. :confused:

#25 carfreak85

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Posted 12 March 2004 - 06:23 PM

If you're worried, GET IT FIXED!!!:D




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