Why don't you just do a fuel Pump Rewire? A lot of guys did it in the DSM, VW, SRT-4 and Nissan community with great results. It could more then probably fair well in our little hondas too? For those of you who doesn't know what it is, it consist of running a bigger wire from the Battery directly to the fuel pump and activate it with a 30amp Relay using the existing fuel pump wire to activate the Relay! Most dudes saw an increase in voltage anywhere from 10 to 12v to 13.5, 14v, thus giving more headroom for tuning as it also increased the fuel flow and pressure in the process... It could hopefully helps us achieve safer AFR when using a Test-Pipe or WR Manifold in conjunction with a Header, Cat-back, Air Intake, ported lower plenum or whatever else you could do...

Read this for further info!!

Why do you need a fuel pump rewire? - SRT Forums - SRT4, SRT6, SRT8, SRT10 & Dodge Forum

http://forums.maxima.org/all-motor/5...low-rates.html

Stealth 316 - Fuel Pump Re-Wire

Lemme know what you think about this!

Marko!!

 

Really not a good idea to over stress the fuel pump motor, which you would do by giving it more power. And how do you know how lean your running or how much fuel you would add by adding the power to the pump. Not to mention if your battery is low on power, you will run extremely lean and possibly blow the motor (Many cars we own at work have had this happen)

Best bet is to just suck it up and get emanage at minimum and get a tune.

 

Looks pretty silly/useless to me. Any increase in fuel delivery obtained by methods such as this one will be erased by the ECU within minutes. It has a target a/f ratio, and it uses the o2 sensor to adjust fuel trim to match it. And this is a good thing - it means that when we increase airflow, the ECU will notice the leaner condition & add fuel to compensate. Speed-density systems are more flexible than people give them credit for.

 

The fuel pump will only take what it demands in terms of current. As for voltage, you are simply reducing the voltage drop ensuring it is getting 12 volts and 13 volts is within the tolerance range of a 12v fuel pump.The fuel pump would benefit so yes, this is in favor of your fuel pump.

I don't know anything about the factory Honda Fit unit so the voltages could be wrong as well. I have done this on a different car with after market fuel pump. Best bet is to leave it alone as this is completely not needed.

I don't think it will help on your AFRs though. I could be wrong but the L15 in your Honda FIt most likely just isn't going to have the demand, not even with 310cc injectors.

 

Granted it's only a solution on the cheap, it would be far more effective to run a piggyback but pretty more expensive too!! The rewire is effective to an extend!! :P And you have the right to tell your opinion too so it's kool!

I'm not sure the ECU will compensate at WOT for Header, test-pipe, etc... (Wich is the point anyway!) as the car switch into open loop at WOT! It will compensate in part throttle as the car runs into closed loop!

http://www.aj-racing.com/ajpwr/Fit/T1RheaderdynoGD3.jpg

Check this out! The numbers down low in the graphs are AIR fuel ratios... As we can see, it doesn't compensate enough for the mods they did... Let's put a test pipe or intake manifold on that car and see what happens!


I suppose the guys doing that mod have a wideband or a dyno facility with wideband support... As i said, i would do this only if i had a Header, Test pipe, Air-intake, Cat-back, etc.... Plus i'm not sure giving normal alt. voltage will blow a fuel pump, it's not like you're giving it 120v! Ignition coils with a CDI box does not blow that much easily even with the 450v - 500v input they give them... If battery voltage is too low, voltage to the pump will be even lower with the stock wiring as there is more resistance in the smaller wires!

Marko!!

 

In closed loop, the ECU adjusts short term fuel trim . . . and short term fuel trim in turn changes long term fuel trim. And that affects open loop operation when the ECU ignores the O2 sensor. But long term fuel trim (as the name implies) isn't immediate - it takes a little time.

Although I certainly can't speak for T1R, I'm guessing that they dyno'd the car right after installing the new part(s) - and didn't give the ECU a chance to adjust long term fuel trim for WOT operation.

 

Hummm what you says make sense! i'm gonna check out with my scanner tomorrow if my ECU reads or ignores fuel trims at WOT just to make sure!

Marko!!

 

Finally, i checked out how-much voltage the pump did recieve stock and found it recieves a healthy 14.2v stock from idle to redline thus negating the effects of the rewire on a fit!!

Marko!!