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Old 07-25-2008, 03:59 PM   #1
subiefast
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Is it a good idea to run both fuel pumps to the stock relay?

I see a lot of people are running it to a power source, and having the second pump activated by a pressure switch.

I'm going to rewire my fuel pumps soon, I have both hardwired to the ignition. I dont want to wear out my pumps too soon.
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Old 07-25-2008, 07:53 PM   #2
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Some trigger their pumps off a switch, some run a relay off the ground wire of the stock pump, and run the power line right from the battery to the second pump, so both always run.
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Old 07-25-2008, 10:11 PM   #3
subiefast
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I'd rather not run it straight from the battery. I dont want to kill my battery.

I'd like for the ecu to control the secondary pump as well. So it's not running all the time.
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Old 07-25-2008, 10:33 PM   #4
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Quote:
Originally Posted by subiefast View Post
I'd rather not run it straight from the battery. I dont want to kill my battery.

I'd like for the ecu to control the secondary pump as well. So it's not running all the time.
If by "kill your battery" you mean drain, its not as if the pump runs with the car off. But pulling the power off the battery, wont affect the battery, and will provide the best voltage to run the pump.

The stock ecu won't be able to "trigger" the second pump to come on unless you have a standalone, or a utec. You can use a hobbs (pressure switch) to make the second pump to come on at a spcified boost level, but you may run in to a rich afr area when the pump comes on.

Phil from element reccomends running both pumps all the time, and running a aftermarket FPR.
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Old 07-26-2008, 12:18 AM   #5
subiefast
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Quote:
Originally Posted by xerox445@yahoo.com View Post
If by "kill your battery" you mean drain, its not as if the pump runs with the car off. But pulling the power off the battery, wont affect the battery, and will provide the best voltage to run the pump.

The stock ecu won't be able to "trigger" the second pump to come on unless you have a standalone, or a utec. You can use a hobbs (pressure switch) to make the second pump to come on at a spcified boost level, but you may run in to a rich afr area when the pump comes on.

Phil from element reccomends running both pumps all the time, and running a aftermarket FPR.
I have both pumps wired to my ignition right now, so they're on as soon as I turn on the ignition. It throws a CEL however, and I cannot pass inspection this way. It throws a "fuel pump circuit malfunction" code since it is no longer wired to the ecu.

I'm trying to figure out a way to include the ecu in the loop so I can make the ecu happy.
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Old 07-26-2008, 12:38 AM   #6
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Why not have it still wired to the ecu? You can have the ecu signal trigger a relay. I'll be running a hydra in which you can have it turn on when certain parameters are met, but if Phil recommends to run both pumps all the time I probably go that route.
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Old 07-26-2008, 12:50 AM   #7
subiefast
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That was my question. I was wondering if I could wire both of them to the ecu. I'm not sure if I will run into problems with that. I think it would be easier if the ecu could control the duty cycle of both pumps.
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Old 07-26-2008, 10:03 PM   #8
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Just ran into this with my build. Phil recommended to run both pumps all the time with an aftermarket FPR, rather than switch the second pump on with my Hydra (or whatever ECU). Also, my tuner said the stock system/relay does not have enough current to run both fuel pumps.

I have the second pump's positive side hooked directly to the battery with a 30amp fuse. Then I put a second Bocsh style relay in to switch the negative side. I soldered a lead onto the positive side of the stock relay coil. I hooked this onto one side of the secondary relay coil. The negative side is hooked to a factory grounding point and then paralleled over to the common side of the secondary relay. Finally the secondary pumps negative is hooked to the NC side of the secondary relay.

This way both of my in-tank fuel pumps trigger off of the ignition, but the secondary pump is powered independently. Hope this helps.....
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Old 07-27-2008, 03:06 AM   #9
subiefast
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I think I'm going to try to run one pump to the stock relay, and the other pump the way you did to a secondary relay.

Hopefully this will make the ecu happy, and the second pump will be running all the time.
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Old 08-02-2008, 09:32 PM   #10
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Quote:
Originally Posted by inov8tr View Post
Just ran into this with my build. Phil recommended to run both pumps all the time with an aftermarket FPR, rather than switch the second pump on with my Hydra (or whatever ECU). Also, my tuner said the stock system/relay does not have enough current to run both fuel pumps.

I have the second pump's positive side hooked directly to the battery with a 30amp fuse. Then I put a second Bocsh style relay in to switch the negative side. I soldered a lead onto the positive side of the stock relay coil. I hooked this onto one side of the secondary relay coil. The negative side is hooked to a factory grounding point and then paralleled over to the common side of the secondary relay. Finally the secondary pumps negative is hooked to the NC side of the secondary relay.

This way both of my in-tank fuel pumps trigger off of the ignition, but the secondary pump is powered independently. Hope this helps.....
Thats exactly what I did. I havent actually ran the car in awhile, as its still being built, but was wondering, how loud are both pumps on together?
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Old 08-02-2008, 10:23 PM   #11
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Quote:
Originally Posted by subiefast View Post
I have both pumps wired to my ignition right now, so they're on as soon as I turn on the ignition. It throws a CEL however, and I cannot pass inspection this way. It throws a "fuel pump circuit malfunction" code since it is no longer wired to the ecu.

I'm trying to figure out a way to include the ecu in the loop so I can make the ecu happy.
You can flash that code out with opensource programs
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Old 08-03-2008, 05:20 AM   #12
tino
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Quote:
Originally Posted by xerox445@yahoo.com View Post
Thats exactly what I did. I havent actually ran the car in awhile, as its still being built, but was wondering, how loud are both pumps on together?
you can hear them very easily when outside the car. or with the back seat removed..
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Old 08-03-2008, 07:33 PM   #13
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U guys should post some pictures of your intank setups.
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Old 08-03-2008, 07:46 PM   #14
methaddict
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Anyone have a link to the diy for this?
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Old 08-05-2008, 02:45 AM   #15
inov8tr
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Quote:
Originally Posted by methaddict View Post
Anyone have a link to the diy for this?
I ended up sending my in tank assembly out to Buschur Racing to let them do the double pump conversion. It turned out well and was worth it. I didn't feel like running all over trying to find all the materials.
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Old 08-05-2008, 03:56 AM   #16
subiefast
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Quote:
Originally Posted by methaddict View Post
Anyone have a link to the diy for this?
Just get a Y barb fitting for the fuel line, and T the second pump into she same fuel line as the primary pump. Wire the secondary pump to a pressure switch or even a hobbs switch, and run that to a power source like the battery.
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Old 08-05-2008, 03:57 AM   #17
subiefast
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I'm wondering how you guys monitor your fuel pumps? I'd like to know if one of them goes out.
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