Rewiring your fuel pump [Merged 9-6]

[nine5raptor]

yes

 

[98TsiAWD]

Yes it is the same, but the AWD has ALOT more other wires going into the pump. Just take your time and make sure you are cuttin and splicing the correct wires beforehand...

 

[DSMJim]

just use a volt meter and check the car with the ignition on and off to find your 12 volt wire, then you re-wire that one. don't forget to make an extra ground from the harness as well and re-wire the ground to the pump to the chassis of the car too just for the hell of it.

 

[doug]

The 2G AWD fuel pump install VFAQ might have some useful info about the electrical connections at the pump, I don't know.

 

[Laguna739]

thanks all i think im gonna give it a try

 

[Mightyp]

the vfaq is for a 95 spyder, on the fuel pump relay there are two black wires, mine has two black wires also, solid blak (ground) black with silver dots (?) and then a bunch of yellow wires. In the vfaq he taps the solid black for ground, but then taps a blue wire for the 12v, so my question is wicht one do I tap? maybe the yellow one with blue dots, if there is one...

thanks in adv

 

[Mightyp]

found it, it's the yellow wire with the blue strip.

 

[Mightyp]

car didn't not turn over Pease help!!!!

 

[KRAZYKOREAN]

WHen you were loosing the fuel line that goes from on top of the fuel pump to the motor....did you twist it when you where loosening the bolt...WHen I did it i didn't realize I was turning the fuel line and then it just kinked up..so I had to turn the line the opposite so it would unkink..and that was my only problem....

 

[Mightyp]

Originally posted by Mightyp
car didn't not turn over Pease help!!!!

It's somthing to do with the ground, I have finally got the car started
but, when it's off the fuel light comes on...

acording to the vfaq I run my own new ground, connected to the old groud that came out of the fuel pump connector.... here is a quote

"Cut the black wire (original ground) running to the fuel pump connector as shown. The part of this wire running to the fuel pump will still be used (ground). The rest of this wire which disappears into the harness is no longer used."

if I don't use the ground that gose back into the harness, my car won't start.... right now I have the new ground, the ground going to the relay, and the old ground all tapped together and she started. I'm going to take it for a test drive. PLEASE SOMEONE TELL ME WHAT THE HELL I DID WRONG! another 2o min MOD, that has takin me all bamn day

 

[Mightyp]

I think I have a answer,... Just got done witht the test run, and the car halled azz... When I sqeezed the relay, it buzzed and the gas light went off, when I sqeezed it agian it buzzed agian and the gas light came back on... hmmm I think it's the relay, or maybe I'm still wiring it wrong, and turned my relay into a wierd switch. pondering this for a while

 

[candela]

WHen you were loosing the fuel line that goes from on top of the fuel pump to the motor....did you twist it when you where loosening the bolt...WHen I did it i didn't realize I was turning the fuel line and then it just kinked up..so I had to turn the line the opposite so it would unkink..and that was my only problem....

When you did it?

 

[brads]

One of the black wires should have a blue stripe on it, the other black wire shouldnt. At least according to my 95 manual. Treat the black wire with blue stripe, the same as the blue wire in the VFAQ, and the black wire the same as black wire in the VFAQ. Don't mess with any of the yellow wires.

Here's a post from DSMTalk where someone else was doing a 2G AWD rewire:

http://www.dsmtalk.com/forums/showthread.php?threadid=85077

Brad

 

[KRAZYKOREAN]

Originally posted by candela


When you did it?

Oh sorry you kinked my fuel line....

 

[Mightyp]

yea the yellow and blue wire was not the right wire, I used the black and blue, and evrything is working great. thanks to all!

100% diffrence at WOT

 

[MaxBoost]

It's so easy that its just plain worth the time and effort. My car ran smoother after the rewire and the voltage was higher and far more stable. Just my opinion.

190lph pump
Big16G
stock injectors

 

[MaineDSM]

Originally posted by smokehouse_83
If everyone is so worried about the relays why dont you just rerun the stock wire with a bigger gage wire? Drew

Because it runs about 30 feet, all around the car, feeding a bunch of different things. It would be a crazy, insane job.

 

[Bohrn]

oh man, your not just whistlin Dixie!! that would be hell!! all under the dash, all in amongst the wiring harness for all sorts of stuff, splittin off to and fro, just a general cluster-mess! To say the least.

Once I worked at a junk yard, and I was asked to take the wiring harness outta a truck. It was a Diesel(way less electronics), it was an 85 or so(way simpler) and it was a rusty piece of crap, and so it did not matter if I wrecked the truck at all. And it still took me most of the day to get all of it, with all the connnectors intact etc.

 

[jdk906s]

Originally posted by HighPsi91
Yes, the fuel pump rewire mod is the most over suggested waste of time in history. If anyone would actually hook up a voltmeter to the voltage supply at the pump and go drive around they would see they have great voltage. The only way this is needed is if you are running a much larger than stock pump at much higher than typical gross fuel pressures. In this situation the larger pump has significantly increased current draw therefore causing a voltage drop on the factory wiring. Its very possible that a supra pump on a fairly high boost car could actually need this mod. I never tested a supra pump so I dont know for sure. However I can tell you a rewired stock pump will do NOTHING. And the typical smaller upgrade pumps do not need to be rewired either.

Not saying your comments aren't without merits, but I did test mine out. Overall, the rewire did increase the voltage during a good deal of the time. Idle went from 11.59 to 13.4 for instance. During quick accell it went from 11.2 to ~14.

Mine's a 1990 Tsi - perhaps it isn't as important on the later model dsms,

 

[MaineDSM]

Originally posted by HighPsi91
However I can tell you a rewired stock pump will do NOTHING.

This is untrue. The rewire on my stock 2G pump raised the base fuel pressure 2psi. Not a lot, but not "nothing".

Here is some more proof: http://www.roadraceengineering.com/fuelpumpflowrates.htm

Notice how the stock pumps flow more at the higher voltages the rewire allows. Once again, many of us have tested the voltage at the pump with and without the rewire, and it *IS* higher. Therefore, this chart is relevant.

 

[kpt4321]

Originally posted by Thrawn
Would it be truthful to say that if I tested my wiring and it tested good at around 13.7 volts, it would be OK to turn the boost up to what a rewire would allow you to run? (ie. 18psi on 14b)

Who says you can seftely run 18 psi on a 14b? That's something you need to decide for yourself with logging, but I wouldn't run more than 16 psi with stock injectors and a stock pump on any car. Even 16 psi is sketchy with a stock pump.

In my car, with the "famous" upgraded fuel lines, I was pushing the limits at 17 psi on a 14b and 450's and a 2.5 inch exhaust. Now that I have a 3 inch, I can't run more than 15 or 16 without knock.

And, on any car with 660's or smaller injectors, big fuel lines don't matter. Trust me, I've logged the difference.

 

[Bohrn]

I kinda figured that the stock fuel lines would be good for more...

and I am glad that someone measured the voltages, I'm too lazy/scared to let someone drive my car at WOT with me in the back, taking voltage readings

 

[jdk906s]

I'm suprised no one else brought this up, but almost all upgrade fuel pumps are designed to work at 14 volt and can whine like banshees when they don't get a full 13.5 + volts.

 

[MaineDSM]

Originally posted by kpt4321

And, on any car with 660's or smaller injectors, big fuel lines don't matter. Trust me, I've logged the difference.

I've never understood the logic behind the Stevetek fuel system. It's based on the theory that the stock fuel lines can't flow fuel efficiently enough, as far as I can tell, so they tell you to redo the entire system with custom AN lines, fittings, fuel filter, etc etc. Major pain in the ass, quite expensive. Just so you can use a stock fuel pump. with no AFPR.

Well guess what. You throw in a upgraded fuel pump and an AFPR for less money and MUCH less time and heartache.... and what do you know, it flows enough fuel for 600hp. So much for the stock lines being a big problem.

 

[symple]

I did my rewire today. Before the rewire, my A/F gauge would never read full rich, now it does. I know (autmeter) A/F gauges aren't exactly accurate, but it seems to have helped. For $15 and the ability to return to stock in 5 secs flat if something goes wriong... hell, why not!


--Symple