I've been seeing people saying they have had to run it at 12v. The stock pump recieves 6v I'm guessing. How do I get the pump a good 12v source?

 

bump

 

Just wire it up to the stock lines and you will be fine.

 

I've heard NOT to wire it up to the stock lines

 

I wired mine up the the stock clip and its running great.

 

The issue with putting it on the stock lines is that the FD fuel pump system is dual voltage, I believe it's 12V normally and then 13.5 under boost or something like that. The Walbro is said to be less reliable in dual voltage situations.

 

How do I get it to be 12v constant? Is there a nearby wire I can tap?

 

No, you'd pull a wire from the fusebox up front.

Note that rewiring for fulltime high voltage makes the thing run rich at idle, and spit and sputter a ton when cold. Nothing bad, just expect it. This is a common mod with fc;s which also have a dual voltage setup, which varies between 9 and 12.5 vdc. I consider it just part of the install, most of the time.

 

or get a supra tt pump which is more reliable and outflows it no brainer

 

Are we talking about stock MKIV TT supra pump?....meaning if i took my friends pump out of his car and put it in mine?

 

You can short out a relay up front near the intercooler to get it to be 12v fulltime. Just did it last month and saw a post either here or on the other forum with pictures that showed me how to do it. It's easy once you see the pictures.

 

Sure, but how's your friend going to feel about not having a fuel pump?

 

darmy can you please find those pictures for me or the thread?

or if anyone else knows what thread he's refering to

thanks!!!

 

Yeah, I'd like to see these pics also. I know the saying "if it's not broke don't fix it" which has been argued greatly on this forum, but my pump works fine, but im having mixed thoughts of running this just on high.

 

it was an example hehe.

 

The primary reason for the dual-speed fuel pump is noise. For example, if you have a box fan on high speed, it's loud and roars constantly, but on low speed it's nearly quiet.

Fortunately for us, the gas tank is pretty well isolated and a full-time 12v pump isn't *that* noisy. I seriously doubt running the pump at 12v full time would compromise the life of the pump - I've yet to see one fail because of this. I think the dual-speed is primarily for noise. The noise is pretty minimal - a small whine coming from the back.

The fuel pump resistor relay is under the cruise control module on the FD. It's just that - a relay and a resistor. Switched one way, the current goes through the resistor, which drops the voltage to 9v. Switched another way by the ECU, the fuel pump gets the full 12v. 5 minutes with the shop manual and a jumper wire, and you can bypass the resistor and see if you like it at 12v full-time.

In theory, the car can run richer and idle richer with the fuel pump at full speed. But, there's so many other factors you'd really need to try it to determine if that's the case. If you're at the point where you need better voltage and a bigger fuel pump, you likely have some sort of aftermarket EFI where you can tune the idle in better.

BTW, I see NO reason to upgrade the fuel pump on a near-stock car.

Haven't tested the FD yet, but I pioneered the fuel pump mod on the FC back in the day. The FC had a substantial voltage drop on the wire going to the fuel pump - I saw as little as 11 volts at full throttle with accessories (lights, AC, stereo, etc.) on. The lower the voltage, the less flow you get from the pump. The solution is running a dedicated power wire from the battery to the pump that's switched by a relay - the relay is switched by the stock fuel pump wire.

That said, the wiring inside the tank to the pump itself is more than adequate. If you'd like to test the fuel pump voltage, rig up a multimeter to the fuel pump power wire and do some testing. That will tell you if it's an issue or not.

Dale

 

Dale, the FD's do have the dual voltage resistor, I rewired around mine when I put the walbro in. Doing a rewire richens the mix at idle with everything else being equal, it raises fuel pressure a little. I dont think the reason for the dual voltage pump is noise, but rather gas mileage.

 

Makes sense - might be the higher flow just overwhelms the stock FPR to the point where you get a richer mixture. I wasn't sure of how the FD would react.

It would be interesting to test it out with a fuel pressure gauge and see what the results are.

The rich idle also might not apply to a rewired stock pump - the Walbro just flat puts out a LOT of fuel. A rewired stock pump might not overwhelm the FPR like the Walbro does.

Dale

 

My car runs like dogshit when it's first cold...it does hold a steady (rough) idle but when you drive it under load it bucks lightly and pops/backfires and runs excessively rich until it warms up, I attribute this to the fuelpump and rewire. My only other mods are exhaust, nonsequential, and emissions removal. The car runs pretty damn smooth when fully warmed up to 190 or above, which takes it about 15 minutes.

 

I vote for the Supra Pump...Not noisy...actually I cant hear it over my exhaust.

 

Here you go....

http://www.nopistons.com/forums/inde...walbro+install


This way you use the stock wires, and still get 12v all the time, with minimal fuss.

 

i have a question.... cant you just rig it up to a switch so that when you drive normally... to work, cruise, go out with gf, etc. you can have it swtiched to its stock settings so that you dont run rich wasting fuel and such when you dont need it. And when you race... just flip a switch that's routes a straight high voltage to the pump bypassing the resistor? So you basically run full voltage when you need to...
(this is a question/suggestion so please give feedback)

Jeremy

 

IN theory, that's what the resistor does stock. Drops voltage at idle and cruise to save gas, and raises it when under boost (I'm not sure at what level it is triggered) to 12vdc.

 

But when you have a walbro... isnt it bad to have it going low high low high all the time expecially if you're on the track or coninuosly racing? because when i cruise and stuff i basically dont go past 3 unless on freeway so its better to have it at stock setting so it's switched to low... but when i race id rather have it full voltage at all times so no matter what i know my pump isnt going low high low high low high. And from what i researched the walbro only spits fuel like crazy and not needed is when the engine is cold due to full voltage... but my motor wont be cold when i race... itll be more than just "warmed up".and when im done and driving normal again i can just switch it back to normal settings.
** again this is just a suggestion and theory therefore needing much feedback **
(I'm helping you out gamezilla )

Jeremy

 

no one?