Upgrading Your Fuel Pump Wiring (4th Gen)

It makes sense but it seems contradictory to previous discussion (quoted above) and the wiring diagram. According to the diagram it is necessary to keep existing +12V feeding the FPCM B+; we just splice a connection from here to the 86 on the relay.

If you do not understand how to wire this with the drawing provided by SBT, I would stop right where you are and take it to a tech that understands wiring.

If the franz only got the pins for the fuel pump, fine, I don't care....from what I understand the other pins are available as well....so not sure why you quote him

If you don't want to source the FPCM plug pins, pop the existing pin out, bend the tabs open on the existing pin/wire and solder the new wire onto the pin and feed it back to 86 on the new relay and bend tabs shut. THEN PUT PIN BACK IN CONNECTOR! NO SPLICE that way! Pretty simple really.

I don't know where you get the idea I said to PERMANENTLY remove that pin.

I said pop it out solder to it and I would think you would understand to put it back. LOL!!!

That way you are not SPLICING!

Im not contradicting anyone, in fact I am the original guy that fixed this problem along with zorro.

Lastly please delete your "modified" pictures, this will do nothing but add to the confusion and cause more people to ask more questions....

Look at the wiring diagram SBT put up for everyone and I think you will answer your own question.

 

With that said, the answer is yes/no as I am not really understanding you statement.

 

The original B+ wire at the FPCM comes from the FACTORY fuel pump relay to B+ on FPCM This is one of the culprit wires that is way too small.

 

This wire needs to BOTH feed the new relay AND the FPCM

It feeds voltage to the FPCM but it also needs to feed the NEW RELAY coil to "SWITCH" it on, which provides voltage from the battery to the pump.

 

This way you have voltage turning on the new relay for the battery voltage direct to the pump AND you have voltage feeding the FPCM so the negative lead to the pump is Pulse Width Modulated

If you do not understand how to wire this with the drawing provided by SBT, I would stop right where you are and take it to a tech that understands wiring.

I do know how to read wiring diagrams; I am just trying to simplify the wiring/soldering for a clean install. There is no need to criticize. I will delete my previous posts.

I do know how to read wiring diagrams; I am just trying to simplify the wiring/soldering for a clean install. There is no need to criticize. I will delete my previous posts.

I agree about the clean install hence my posts about the pin. Your initial question was do I have to splice.

I answered, pop the pin out of the module and solder/crimp the new wire for the relay right on the pin. Neat and clean.

You either connect it at the pin or splice it in the middle of the wire. Your choice.

Regardless, that wire has to feed two places, so really it's some sort of "splice" to the existing module and the new relay.

I'm actually not sure why the initial question. If a factory wire needs to feed another new relay it has to be "spliced" somewhere.

These two threads have been literally beat to death with people trying to reinvent the wheel, hence the frustration.

I would have thought SBT doing the wiring diagram and parts list would have ended all the questions.

Heck I had one this week, what parts do I need. Really? Are you kidding me. If people would just read the thread and study it out its all spelled out for them.

 

Heck I had one this week, what parts do I need. Really? Are you kidding me. If people would just read the thread and study it out its all spelled out for them.

I only asked you because you're helping me with it this weekend lol

Well we installed zero1's fuel pump upgrade this past week into his 08 spec B and what did we find.....

The wiring is the same size as the STI!!!!!!

I guess the Spec B is special after all

Anyway we went ahead and wired the DW kit with relayed direct voltage to the pump but left the rest of it alone. Not sure we even needed to do that......

Here are a couple pics of the wiring.

That last pic just shows how we flipped the module mount and and bolted the relay but was by no means buttoned up

As you can see the wiring is as large or larger than an STI and I would guess really nothing needed to be done to this.

Ben will be running a rotated setup so we thought to just run direct battery voltage to the pump anyway.

We just popped the pins out of the module connector and the pump connector so we could return it to stock later if needed.

When done with the modified fuse installed we had 14.8 volts at the pump area on a cold startup day.....

http://img.tapatalk.com/d/13/12/23/gyrahe7e.jpg

http://img.tapatalk.com/d/13/12/23/a8umu6y3.jpg

http://img.tapatalk.com/d/13/12/23/reha6aze.jpg

I probably mostly needed every bit of juice we could squeeze out of the new Full Blown 340lph pump... because I'm probably going to need a secondary pump to go with >.<

And thank you again for the help Scooby2.5

very good write up and very detailed. going to look into doing this for mine.

side question has it been attempted to utilize an amplifier like that of a kenne bell boost a pump, where you can dial in gain to increase voltage? jw.

know little comparitively from ford vs subaru regarding boost a pump usage on fords and the dccd fuel pro controller mentioned above by someone else.

havent pulled my seaT to see for myself, but is that a transfer pump on the ds part of the tank or just sensor etc?

Hey Scooby2.5,

Awesome info here...well done...I had a questions....if you don't mind...

I have a spec B GT Australian model....

I have a DW Hardwire kit, and I was looking at the install with zero1...

So I think I know that the black wire from the relay gets spliced into to red/black wire on the Module...is that correct.?

And the White from relay is earth

And blue from relay goes to battery

I'm not sure where the yellow goes? The DW instructions says fuel pump....

Just wanted to see what you did on zero1's thanks advance for your help

Cheers jack

Best bet would be to download the PDF file that SBT drew up and follow that. The relay in his drawing is labeled with numbers for each pin.

Then look at the DW plug (which has blue, white, yellow, black) and the relay (should be numbered similar to drawing) provided and match it up.

Well we installed zero1's fuel pump upgrade this past week into his 08 spec B and what did we find.....

 

The wiring is the same size as the STI!!!!!!

 

I guess the Spec B is special after all

 

Anyway we went ahead and wired the DW kit with relayed direct voltage to the pump but left the rest of it alone. Not sure we even needed to do that......

 

Here are a couple pics of the wiring.

 

That last pic just shows how we flipped the module mount and and bolted the relay but was by no means buttoned up

 

As you can see the wiring is as large or larger than an STI and I would guess really nothing needed to be done to this.

 

Ben will be running a rotated setup so we thought to just run direct battery voltage to the pump anyway.

 

We just popped the pins out of the module connector and the pump connector so we could return it to stock later if needed.

 

When done with the modified fuse installed we had 14.8 volts at the pump area on a cold startup day.....

I was about to do the wiring upgrade on my 07LGT with the DW kit. I noticed the wiring on mine is the same as above(as larger or larger than the STI). They must have switched mid year?

I've got the DW65 pump running an HTA68 with ID1000 injectors. Anyone see the need to perform the wiring upgrade or would the stock larger sized wiring be good enough?

Edit - Just checked it with a volt meter and at 100% duty cycle, the pump only receives 12.48 volts. Battery is 13.6.

CapnJack - if your IDCs are reasonable then there is no reason to upgrade the wiring. 12.48V is already significantly better than what has been observed with the smaller wiring.

I am curious why people are adding a new fuse/relay/line rather than running a parallel line in the stock wiring. Not even sure if the entire circuit needs to be done. I will measure the resistance across the following junctions:

M/B Fuse #11 -> FP Relay

FP Relay -> FPCM

FPCM -> FP (x2)

FPCM -> GND

I'm guessing it's the two in bold that are the problem, which could be solved with three lengths of wire. This avoids running a separate dedicated power feed with a redundant fuse and relay. I'm only proposing this because I am adding ~6 circuits via a separate panel and trying to optimize the wiring.

I can take this to a new thread if you prefer, but here is a schematic:

M/B Fuse #11 -> FP Relay

FP Relay -> FPCM

FPCM -> FP (x2)

FPCM -> GND

http://imageshack.com/a/img673/6692/QrUnau.jpg

CapnJack - if your IDCs are reasonable then there is no reason to upgrade the wiring. 12.48V is already significantly better than what has been observed with the smaller wiring.

 

I am curious why people are adding a new fuse/relay/line rather than running a parallel line in the stock wiring. Not even sure if the entire circuit needs to be done. I will measure the resistance across the following junctions:

 

M/B Fuse #11 -> FP Relay

FP Relay -> FPCM

FPCM -> FP (x2)

FPCM -> GND

 

I'm guessing it's the two in bold that are the problem, which could be solved with three lengths of wire. This avoids running a separate dedicated power feed with a redundant fuse and relay. I'm only proposing this because I am adding ~6 circuits via a separate panel and trying to optimize the wiring.

I'm looking to retune in the spring and push it some more. My idcs were good on the aeromotive 340 pump, but I stepped down to the dw65 since they seemed more e85 friendly. My 340 started dying.

Where is the FP relay located? I was thinking it was in the front of the car.

FP relay is behind the glove box almost directly to the right of the cabin filter holder.

http://imageshack.com/a/img661/1576/VOj2qj.jpg

Completed this mod a few weeks ago and finally got around to a systems test yesterday. Initial key-on fuel prime sequence yielded zero voltage to the pump. Rechecked circuitry and swapped STI FPCM (from eBay) for LGT FPCM and all is well. Bummer about the ~$40 wasted, but I'll tinker with it to see what I can learn.

The only obvious difference inside the case (or out for that matter) was the markings on the capacitor were slightly different.

Hmm, do i feel a DIY lgt fpcm upgrade coming on? Is there a rom chip or anything inside where alternate programming could be?

Sent from my XT1028

I did the upgrade 2months back, the throttle was so doughy...and that was with a DW V2 300...I recently fitted a walbro 460...a much better pump for e85....throttle even more doughy...haha

Now for a retune

http://i1216.photobucket.com/albums/dd368/jacks-GTB/4EC20436-1348-4EA7-81B6-6E6349BFC52A_zpsidbt79xh.jpg

Could be a "mechanical" problem too. Bad seal with o-rings in the fuel pump assembly (3 joints to seal in there), maybe a "clogged" oem filter housing, etc.

Sent from my XT1028