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DIY - How to hardwire your fuel pumps and keep all controller functionality

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#1
NickTO

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ok,  so this is not a kit, but an overview of how to re-wire for your pumps to get full current while still maintaining the primary pump controller functionality.

 

With this setup there are no DTCs triggered.  The Secondary pump gets triggered by the ECU as usual.  

 

 

You will need 2 relays, separate 20A fuses (one for each pump circuit), and perhaps a bigger 50A for the new power source.  A generic hardwire kit will get you most of the components

 

A couple veterans have used this (socalaviator?) with success.  I've helped quite a few people on the old board run this setup.  None reported any errors, so if you used this before and have feedback, do post it here!

 

You don't need to get the power source the same way I did as I already had a 4 gauge wire coming from the battery for an upgraded subwoofer, and from there used a an previously installed power distribution block to run 10 gauge to the pumps.   There's better pre-fused power brackets that can do this nicely though.

 

 My 10 gauge may be overkill as well for you (that's what I had on hand), so you should figure you what gauge you want to run based on the current requirements of your pumps.

 

The secondary pump relay can be installed right next to the original one in the trunk , right side pocket where a dual relay bracket (with the one relay on it) is installed.

 

I've attached two documents.  One if the OE wiring diagram for the ECU, the 2nd is the modifications I've made to my wiring.   It involved cutting 1 wire, mainly the power feed INTO the Primary pump controller, and using it to drive a relay instead.   From there, the bigger gauge wire takes over.

 

If anyone has questions on the inner working and can't figure it out by looking at the modification diagram, do ask!   But the answer is no, I don't have a kit to do this, I just put it together with whatever I had.   Some vendors may be coming out with a kit following this recipe, but I have no insights into what that entails.

 

 

OEM wiring diagram of ECU: Attached File  jtbwa0479gb.pdf   268.46KB   2743 downloads

 

Modifications made to wiring:  Attached File  FuelPump-Modification.pdf   112.68KB   1848 downloads


Edited by NickTO, 03 April 2014 - 01:35 PM.

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#2
shawnhayes

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Thanks man.

 

On top of it as always.

 

Will add to registry...

 

Shawn



#3
Buschur Racing

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I want to add some input to this thread.

 

I didn't want Hobb switch on my GTR and with as complex as the wiring/ECU is on the car I really wanted to keep as much of the stock system as complete as I could.

 

I happened across Nick's wiring somehow and contacted him before this was posted to ask if he'd help me with it.  He gladly did and we wired up my GTR per his instructions.

 

A few months ago before we built my car I was driving and got a CEL for P0627, did some research found it was common.  I re-set it a few times and finally it was gone and didn't come back.

 

This last week after finishing the build on my car I was on the dyno and the code popped up again.  I fought with it and couldn't get it to stay off.  I made a few phone calls, I was advised this happens when the pumps are hard wired in to relays and to just disable the code, along with a few others.  I like to keep the codes in tact if I can so I only disabled the P0627.  The next pull on the dyno I got no code but noticed the car was now lean up top, so I aborted the dyno run.

I added some fuel and tried again, bottom line was the car was running out of fuel and the VE table was no longer looking like it should.

 

The car came off the dyno and we pulled the fuel pumps.  Ends up the secondary pump was the issue.

 

So what I want to add here is that I'd personally would recommend ONLY wiring the GTR pumps the way Nick has it outlined in this thread and I'd HIGHLY advise NOT disabling the codes as many people do.  It was hell of a good warning for me and I do this for a living.  

 

So thank you Nick for the help with mine last year and for making this public for others.


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#4
FreakofNature

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Hi NickTo,

 

I see what you've done here, nice work.  Two quick questions:

 

1. Primary Pump: You've upgraded Pin 10 along with Pin 7 to Pin 4 to 10 AWG to handle the extra load, however, should any consideration be taken on sizing for Pin 5 to Pin 6 going back to the FPCM?  I'm assuming this module pulses voltage to duty cycle the pump in operating at a lower or higher voltage based on the signal from the ECU.  I just don't know if this unit does so on the feed side or through the ground side via resistance variation. 

 

2. FPCM: Although the wiring is upgraded, have you found any reason to believe that the module itself can't handle the extra load internally?  Any chance we would shorten the life on the control module or overload it with the extra amps running through it?

 

Oh, also, did you cut then solder the connections or did you pull the pins out of the connectors to replace the wire to re-seat them?

 

Thank you sir.

 

Steven


Edited by FreakofNature, 10 July 2014 - 01:52 PM.

Steven

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#5
NickTO

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Good questions.

1. I didn't upgrade the return side pin 5-6, though that certainly could be doable.  I monitored current to the pump and stopped  adding wires when it got fixed.  I did a non-scientific 'touch the wire' and didn't feel that wire heating up so kept it stock.   So overall, the issue I had seemed to be around the current wire length from IPDM TO the FPCM.  I wasn't burning up fuses, but also wasn't able to deliver the amperage to the pumps...

 

I wouldn't discourage someone from upgrading the entire loop, I just stopped where I felt the issue was.  Same thing for ground wire pin 5; I looked at the ground run and it was short enough to a nearby grounding point that I didn't change it.

 

I believe the FPCM modulates voltage on the feed side.

 

 

As for connections, I pulled the pins, but ended up soldering at the wire as close as possible to the pin and running in parallel.  The wire + insulation I used was too large to fit into the connectors.

 

Been running the setup on dual DW65c for over a year now and no FPCM current capacity concerns.  

 

The 'current' reality is the OEM circuit is fused 20A, and my upgraded one is 20A as well, so I have no reason to believe that I'd be shortening the life of the module by pushing the same current the apparatus is spec'd for :)


Edited by NickTO, 10 July 2014 - 02:48 PM.

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#6
FreakofNature

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Good questions.

1. I didn't upgrade the return side pin 5-6, though that certainly could be doable.  I monitored current to the pump and stopped  adding wires when it got fixed.  I did a non-scientific 'touch the wire' and didn't feel that wire heating up so kept it stock.   So overall, the issue I had seemed to be around the current wire length from IPDM TO the FPCM.  I wasn't burning up fuses, but also wasn't able to deliver the amperage to the pumps...

 

I wouldn't discourage someone from upgrading the entire loop, I just stopped where I felt the issue was.  Same thing for ground wire pin 5; I looked at the ground run and it was short enough to a nearby grounding point that I didn't change it.

 

I believe the FPCM modulates voltage on the feed side.

 

 

As for connections, I pulled the pins, but ended up soldering at the wire as close as possible to the pin and running in parallel.  The wire + insulation I used was too large to fit into the connectors.

 

Been running the setup on dual DW65c for over a year now and no FPCM current capacity concerns.  

 

The 'current' reality is the OEM circuit is fused 20A, and my upgraded one is 20A as well, so I have no reason to believe that I'd be shortening the life of the module by pushing the same current the apparatus is spec'd for :)

Thanks man, you're the best.  Also, I'm more confident in your educated guesses than in most people's facts so I'll stick to not doing more work than is necessary to accomplish the job.

 

Cheers!

 

Steven


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#7
Buschur Racing

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I'm running twin 485's wired to Nickto's instructions.


www.buschurracing.com

BR160 package, stock turbofolds, 8.33@168.68 mph, E80 fuel.
BR160 package, stock turbofolds, 8.74@160.08 mph, 93 octane.
Standing 1/2 mile 199.29 mph

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#8
Xsuil

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Great guide .
Pictures of each of the hard wiring steps would be great for us peasant .


rCfhnEM.jpg

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- Topspeed Motorsports 4.0 Engine .
- ETS HTA 3794 Turbo Kit .
- 1460 HP @ 38 PSI
- 1100 HP @ 25 PSI

Phase 2 :
- Topspeed Motorsports 4.1 Engine .
- ETS Little Hero Super99 Turbo Kit .
- 1500+ HP @ 40 PSI
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#9
tgkb278

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Just to verify, no Hobbs switch is needed for this DIY and we can retain the P0627 error code for early pump failure warning?

 

Thanks



#10
Soccerking3000

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just wanted to bump this, I did this this weekend and it worked flawlessly with my 330lph pumps.  I mounted one of the relays right next to the factory second pump relay and the other right next to the fuel pump control module.  IDC went down 12% at redline


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#11
HiBoost

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Nice! Would still like to see you post a write up on your fuel filter setup too ;)
-Jeff

#12
Soccerking3000

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Nice! Would still like to see you post a write up on your fuel filter setup too ;)

 

 

ill do it tonight for you guys



#13
NickTO

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just wanted to bump this, I did this this weekend and it worked flawlessly with my 330lph pumps.  I mounted one of the relays right next to the factory second pump relay and the other right next to the fuel pump control module.  IDC went down 12% at redline

 

Happy it works for all of you!    My IDC went down as well noticeably on top end after doing this.

 

 

You should let everyone else know, just make sure you don't make direct reference to this post on the other forum or you'll be put in moderator queue ;)


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#14
KrieGTR

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Hey guys,

I wired up my car per Nicks write up about 3 months ago. I wired in twin 485's. Everything was running smooth until two weeks ago.
Drove my car to the store, no boost just cruising. Went in for about 30 min. When I went to leave I fired up the car and it had a very rough idle. Barely able to stay at 600 rpm and lopey.
I instantly turned it off then tried it again. This time it wouldn't get to 500 rpm and when I pushed on the throttle nothing happen, it was ignoring my input. 
 
I then had a fellow GTR buddy come pick me up so I could grab my tools to see if it was possibly a bad O ring in the pumps, since I have heard about that happening to guys in the past.
Once I got back to my car it fired up instantly. I didn't want to chance my luck so I drove it home. As I was cruising home, I thought I would give it a little boost and see if it was possibly just a charge pipe thar had came off. As soon as boost came on the car jurked and cut out.
I just babied it the rest of the way home.
 
Well I had to leave on a business trip for 2 weeks, but when I got home on friday the car was completely dead. I took the negative battery terminal off and charged the battery over night.
Today I took out the pumps to make sure non of the O rings had came out or anything looked funny. Everything looked great minus a couple weird looking bubbly holes on the return line that runs on top of the basket. I hooked my battery up to each pump and they turned on fine.
 
I put the assembly back in the tank, reloaded my EcuTek map just in case that was the issue. Went to the testing page of EcuTek and proceeded to test my fuel pumps individually before I fired up my car. At first they both turned one one at a time like I was telling them to. The second tome around, nothing. I click on, I hear the relay for the second pump click but no pumps.
 
I'm at a loss for what my problem is and where to continue to troubleshoot. 
 
Please help? Hopefully nothing has hurt the factory controller?

09' SS GTR BPU

#15
NickTO

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I put the assembly back in the tank, reloaded my EcuTek map just in case that was the issue. Went to the testing page of EcuTek and proceeded to test my fuel pumps individually before I fired up my car. At first they both turned one one at a time like I was telling them to. The second tome around, nothing. I click on, I hear the relay for the second pump click but no pumps.

 

If you activate the secondary pump, hear the relay click, and no pump.  Then there's a relevant diagnosis to be made:

 

1.  The secondary pump does not use the Fuel Pump Controller Module.  It is a relay driven by the ECU.  So you can eliminate the controller as the source as it does not interact with the secondary.

 

2. You heard the relay click, therefore the ECU works and the relay coil is energized.

 

3. Check the power source to the secondary pump, before AND after the secondary relay

 

4. If power is good, your pumps / filters / wires could be the problem.


Edited by NickTO, 01 September 2014 - 06:50 AM.

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#16
KrieGTR

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Nick,

That makes sense and I completely agree.

What's your thoughts that I never heard the relay for the primary pump?
09' SS GTR BPU

#17
NickTO

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You likely won't hear the OE relay for the primary pump.  But you should hear the relay you installed for the new primary pump wire when you turn the car ON.   I would suggest you go close to where this relay is installed, and turn the car on and see if you can hear it, or even take a voltmeter and see if there's power going into the new primary relay coils.   That might indicate something.


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#18
KrieGTR

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I might have narrowed down many issues. 

 

1) Battery won't hold a charge!

2) Possible loose connection on my primary relay.

3) I ran a single 14 gauge mil-spec wire from the battery to both new relay's. It works perfect for the primary pump, but as soon as the secondary pump turns on I lose 1-2v to the pumps. 

 

Fix:

1) Just ordered a new Optima Yellow top D51R battery

2) Check all connections and make sure they are solid

3) Adding a second 14 gauge mil-spec wire so each pump has it's own feed from the battery.

 

I would like to thank Nick for always helping out when I have had questions. Also I want to add that his way of wiring up your bigger fuel pumps with OEM logic is the easiest and best route to go.

 

Thanks again and I'll update everyone after the fix and how the car runs. :-)


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09' SS GTR BPU

#19
NickTO

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Good luck, looks like you've figured it out!


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#20
sponaugle

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Hey Nick,
 
I did a couple of modifications to the wiring for my fuel pump system that are similar to the idea you posted above, with a small change. 
 
Here is a look at the stock fuel pump wiring:
 
FuelPumpReWire2.png
 
You can see how the primary pump is driven off the fuel pump controller, and the secondary pump is directly driven off a relay that is powered by the primary fuse box.
 
FuelPumpReWire1.png
 
This diagram shows the changes I made in red.   I added two relays and placed them in line to the FPCM and the secondary pump.
 
I made these changes, and I am now getting a P0627 Code.  This code only appears after a full throttle run where the 2nd pump is engaged.   I added an LED driven off the lines going to the 2nd pump so I can verify the pump is coming on (and you can hear it if I jumper it on).      The pump is working fine, AFRs are fine etc.   I just get the engine code.
 
A quick look at the schematic and you can see that the output of the factory 2nd fuel pump relay (called SUB FUEL PUMP RELAY) goes to the 2nd fuel pump, a condenser, and back to pin 93 on the ECM.   This pin going back to the ECM is what allows the ECM to diagnose problems with the 2nd pump fuel system. (Note the ground side of the pump is also sent back to the ECM on pin 94, and that is labeled as SubPump- in the service manual)
 
There are three codes related to the 2nd fuel pump:
 
P0627 - Sub Fuel Pump Control Circuit Open
P0629 - Sub Fuel Pump Control Circuit High
P062A - Sub Fuel Pump Control Circuit Range/Performance 
 
In looking at the service manual, it would appear the 2nd code (P0629) is detected if the 2nd fuel pump relay is not being commanded on , and if the voltage on pin 93 going into the ECM is 12Vs.   This would make sense, as the description is the circuit is stuck high.   The diagnostics say to check for a stuck relay.  
 
The 3rd code (P062A) is indicated as being detected if the fuel pump does not activate when commanded by the ECM.  I am guessing that this means the ECM commands the Sub Fuel Pump Relay to turn on, but the ECM does not detect the 12V signal on pin 93.
 
The 1st code (P0627) is described as detecting an 'Open Circuit' in the fuel pump.   The diagnostic procedure has you first check for a good connection between the relay and the pump, and then the pump and the pump ground.   That would imply that the ECM can detect that the pump is not drawing any current.
 
Since my modification has a relay driven by the output of the Sub Fuel Pump Relay instead of an actual fuel pump, I am indeed drawing much less current from that relay circuit.    There is no direct way for the ECM to measure current given it is coming from the Sub Fuel Pump Relay, but it could be looking for a small voltage drop when the pump first kicks on.  It would not see it in this case.
 
First:  Any flaws in my logic?
 
Second:  Is this why you have the relay for the secondary pump in parallel with the stock relay?
 
Jeff

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