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Old 06-20-2012, 02:58 AM   #59
Scooby Specialist
Member#: 73932
Join Date: Nov 2004
Chapter/Region: RMIC
Location: Denver
2005 STi BROtuned
2004 S2000


Originally Posted by C J View Post
Just got a text from my friend who has my car back home, he rewired the fuel pump after reading this thread and now is seeing 13.6v at WOT but no change in fuel pressure...

Next step?
Have they tried the bigger pump with the hardwire in place? Was a larger ground added as well? What size wire did they go with?

Originally Posted by Paul View Post
Move the maf like most people said. Its not hard or that expensive.
I never liked the placement of the MAF as with the BB turbo, you could hear it still spinning when the throttle shut. With VTA, it just makes it that much harder. I wouldn't mind trying a blow-thru setup. A MAF bung/adapter would have to be welded in and likely would want to move the BOV before the MAF.

Originally Posted by Equilibrium Tuning View Post
The pressure drop just means the pump can't keep up. Change to a new pump or a dual setup. Stop chasing your own tail just because you assume this pump from a friend is good. In general, try not to assume anything is working properly until you rule it out conclusively.

It sounds like you need to get your car to a good tuner who can go over the setup, make some necessary changes and spend some time to get it running properly. Your friends might know some things, but properly setting up and tuning a setup like this is not easy especially if you haven't done so before. Hell, just keeping a car idling consistently and not stalling with the ID2000's requires a couple tricks that most amateur tuners will not know about.

-- Ed
Without the MAF plugged in, I could get the 2200's to idle like a stock car. You could barely see a difference between A/C on and off, and it would drop down to idle just fine. Once the MAF was plugged in, it went to hell.

The ID2200's are nice in the fact that I could get a controlled enough spray that I could stay out of hitting minimum IDC. I was unable to do that with the Five-O 1,200cc side feed injectors. They'd drastically bounce from rich to lean at low IDC and most of the time the computer was commanding as low as it could for IDC with the latency doing all the work. Drop the latency to get the commanded IDC up, and they ran like poo.

Originally Posted by C J View Post
If the pump couldn't keep up wouldn't we have seen a change going from a 255lph to a 342lph that has now been rewired?

the pressure drops and holds identically before and after the fuel pump changes.

That doesn't make sense to me if the pump is not keeping up, I think we would have seen some kind of pressure change with the larger pump.

edit: the pump we put in was brand new.
You should see some type of pressure change, but it could have been very incremental if the factory wiring was restricting it. The big pumps require a lot of power to be BIG pumps.
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yamahaSHO is offline   Reply With Quote