Ok, I search for about 1 hour but didnt find a good enough answer, nor a thread from the last 2 years on the subject.

I recently did a fuel pump hot wire, ran a 8 gauge power wire to a relay, then to the pump using the factory power supply wire for the remote switch for the relay. I also used a 8 gauge ground wire for the relay, tieing it into the factory ground for the pump. (always taught if upgrading the power wire, the ground must be the same gauge as the power)

Well anyways, the car runs fine and dandy. Getting 14.4+volts at idle and all, where as it was getting 7.8v. also have seen about .2-.5 decrease in a/f ratio (richened up) so I went for a few logs. Sent the logs off to TouringBubble (my tuner) and he says that the logs seems to be showing the car is now LEANER than before, not alot leaner though. Edit-running .3 AFR leaner at WOT and +3% or so in the fuel trims

Any Ideas why? Did I use the wrong remote wire for the relay to switch the relay on? (factory voltage drop affecting the relay, not allowing full power to pump at higher loads)

***diagrams added***


Factory wiring


My current howiring


The way my Mitsu Tech suggested to wire

 

Cliff notes: ran 10 gauge wire to fuel pump for power, ran 10 gauge wire to pump for ground, Used relay for switching for pump by ignition switch. Vehicle now running leaner where it should be running richer.

 

bump

 

wow, seriously. No help?

This is what I have come up with so far. The first pic is of the factory fuel pump wiring. The second is what I am currently running.


pix moved to post 1

 

bump for diagrams and some help hopefully.

 

Hello?! Is there no one out there willing to help?

 

ok, fixed the diagrams. Now hopefully some one can help

 

74 views with out any kinda of remarks. surprising.

 

It is very odd it went leaner. How much leaner? Maybe it hit lower load cells? Did the car make the same power in both logs?

 

It is at the same power levels, .3 AFR at WOT and +3% or so in the fuel trims

 

What's the car being tuned with?

 

Evoscan and EcuFlash with an AEM UEGO using the serial/usb cable to log realtime A/F

 

Is your tune that tight on the car that you never have a variance such as .3 points of AFR if ambient conditions change? I don't think you've done anything wrong and I would just retune and forget about it.

You aren't going to really see any difference in performance by supplying more voltage to the pump unless you were previously having a pressure drop problem due to it being out of flow or insufficient voltage.

 

Yeah .3 AFR could be a different in temp of air. What was your trims before though. 3% is not bad, that is what my car is stock. Anything below 5 is more than acceptable. I dont think anything is wrong.

 

well, with the factory wiring it supplys 7-8volts to the pump under light load and 10-11 under load. by doing the hotwiring, it is suppose to supply direct battery voltage to the pump causing it to pump more (supply more in theroy i guess)

I did some logs before during the day, then did the hotwire and compairing both logs, the car went leaner. the only change being the hotwire.