dr20t

Ok so wiring all done and cleaned up

Consisting of:

10ag wiring fused at the battery, direct to 4 pin, 30 amp relay pin 30 mounted in the boot (trunk for you USA folk )

10ag earth wiring to relay pin 85

12 ag trigger feed from fuel pump control module red and black wire to relay pin 87

10 ag power wire from relay pin 86 to positive side of fuel pump

10ag wire from fpcm negative output to negative wire on fuel pump

Measured 13.94v at 'key on' and engine idle

This was also before I installed the voltage booster fuse / diode referred to above by Scooby2.5

Haven't tested voltage after the voltage booster install but assuming a 0.5v increased I would say pump voltage is now at 14.4v which is fantastic

Going back for retune on 22nd August so hopefully this problem is now sorted

Thanks again to all for your assistance

Mick

So I completed the wiring upgrade today

Ended up having to retain the stock fuel pump plug. Left about an inch of negative and positive wiring to the plug, then 10ag wiring to the relay for positive, and 10ag wiring to the fpcm for the negative.

Haven't measured the voltage yet as I ran out of daylight - will check tomorrow and report the results.

Thanks to all who contributed to this thread for the help.

Mick

Nice. At 300whp on e85 with the torque available down low, that should do a high 12 say 12.7/12.8 @ 105-10mph

Get your launch and shifts right and it should go there

Mick

I'm running 13.1s on 104-105 traps... Do you have a vid or datalog of a run we can check out?

What sort of dyno numbers are you seeing for 13.1?

Mick

Fair point about it being designed for less current (albeit the exact current it was designed for is unknown as far as I'm aware ?)

I think for now ill chance it, given others haven't had any dramas for over a year. If the fpcm fails due to the high current draw passing through it then I will look into the solid state relay.

For information sake - I'm assuming you'd still keep the fpcm in place although negative output from fpcm would go to the solid state relay input trigger, and output from the solid state relay would go to the negative side of the pump? Trigger would come from the same wire as the mechanical relay (ie the factory power wire to the fpcm)?

But if the fpcm is in actuality a quasi solid state relay then there's no need for that is there?

We have adduced that the duty cycle is achieved via fpcm negative output to the pump varying the earthing voltage. Therefore I'd rather leave it to do its job and just change the size of the wire so as to match the positive output going to the pump.

Surely this would be the best way without overly complicating it with another solid state relay to achieve the same thing (especially when I just paid $100 for the wrx Sti fpcm )

Crystal clear now

The only reason I suggested looking into solid state relay was this is what frank suggested. I think between you and frank I was confused as at times there was conflicting advice which at times was contradictory to your own original posts.

All good and will proceed with the setup I detailed above in post 517

My apologies for any frustration caused and will report back with findings / details

Mick

Haha I do get it frank, really . I know the fpc is basically a solid state - thus the negative regulationod voltage.

I understand now about the solid state being for the negative side. I previously didnt realize this

It's honestly not complicated at all - all I basically wanted to know is whether its ok to switch the positive side relay (which will power the fuel pump direct) with the same power wire that feeds the fpcm. Which you have now answered as yes

And also whether to use a normal relay or solid state - and I now take it that I should run a mechanical relay to the positive side of the fuel pump.

So that means the negative side from fpcm wil already be running though solid state relay (being the fpcm itself) so nothing else needs to change

To summarize / finalize:

1. 10ag wire from battery, fused close to the battery, and run to a mechanical 4 pin 30/40 amp relay.

2. Trigger for relay to come from factory fpcm power wire, and continue to feed the fpcm as well

3. Positive output from relay via 10ag wire to fuel pump positive terminal

4. Upgrade fpcm negative output wire to 10/12ag (whatever I can fit into the terminal) and run this to negative side of fuel pump

5. Tape up / discontinue using positive output wire from fpcm - just insulate it.

6. If I really want to be keen, I can also upgrade positive wire to fpcm so as to reduce voltage drop, which can be done in a couple of ways

I'm sure this will achieve the outcome - which is to get 13.6-13.8v at the fuel pump, yet still have pwm regulation via the fpcm

Mick

That's awesome thanks kc

Is the current draw to turn the relay on significant enough to cause any issues with the fpcm / original fuel pump circuitry.

Also - any reason to suspect the old schools type mechanical relay will not be up to the task of constant pulse width modulation of the fpcm?

Frank's suggestion above was to use a solid state relay - this would require a rethink of the wiring would it not?

As per one of my previous posts, my understanding is when using solid state relays in a system with pwm, the negative output of the pwm controller (in our case the fpcm) needs to go to the input side of the solid state relay itself - is this correct?

Firstly thanks again frank and scooby:

A few things:

impressive sounding car! however i don't think you can use the square wave output of the fpcm to drive a relay, it is too high of a frequency.

 

you can run a heavy wire from batt (with an inline fuse near the batt connection) or from the switched green wire in the steering column back to the trunk to the new relay's pin 87. cut the existing fpcm supply wire (fpcm pin 10) and the harness side connects to relay pin 86. the fpcm side of the cut wire goes to relay pin 30. run relay pin 85 to chassis ground screw. all of that is just to get full power to the fpcm.

 

you can also replace the wires with heavier gauge going from fpcm to fuel pump, and from fpcm to ground.

Correct output wire of FPCM will not control relay as heiche said.

 

 

You have to do it like many others have said and the many drawings in this thread.

 

The wire from the stock Fuel pump relay is used to trigger the new relay.

 

dr20t Why change it from what the pump manufacturers recommend?

 

.

The above comments indicate you can't use the fpcm positive output to trigger the relay. Is this correct? (The relay I would be trying to trigger here will send battery voltage straight to the fuel pump not though the fpcm)

What I plan to do to mine is put larger gauge wire from the module to the pump on both the negative and positive wires just like the STI.

 

Then I am going to feed the FPCM with the relayed battery voltage with the DW kit. This way I have max voltage going to the Module (just like the STI)

 

I will use the TINY old feed line that went to the module to turn "on" the relay.

 

That is the way mine is wired now, I just dont have the larger guage wire running from the module connector to the pump.

 

I purchased a factory STI fuel pump plug and I am going to splice it in or remove the pins and wires to make it as factory as possible.

 

 

The whole point to this was not only was the STI using larger guage wire to and from the module to the pump.

 

The STI had larger wire with more voltage feeding the Module off the fuel pump relay.

 

Our factory wire off the fuel pump relay (actually under the dash on passenger side in US) is too small and drops way too much voltage to use as a feed to the STI module. I guess you can but Im trying to mimick the STI setup and see what happens.

 

If it doesnt work, Ill run the positive side to the pump, feed the module with the factory voltage lead, and use the larger wire from the module to the pump on the negative side as you suggest.

 

Good luck!

Again I know what you're saying and have very clearly understood this point from the beginning. However I think we're getting mixed up about what I'm referring to here.

I never intended at any stage to use the positive of the fpcm to go to the pump. This was always going to be through the new relay I ran so as to deliver the new higher voltage direct to the fuel pump (not through the fpcm).

Also, you're still suggesting to run higher voltage through the fpcm, although several pages ago, when you first linked the nasioc thread and zorro's work, i thought you were saying his way is a better way to do it? That way you don't risk voltage drop through the fpcm?

I'm happy to run it through the fpcm or not - it doesn't bother me either way. Just trying to figure out the best way to wire it and retain full pwm from the fpcm, whilst getting maximum possible voltage to the pump.

My logic here was if I'm running direct battery voltage to the fuel pump via a relay/ 10ag wire, there was no need to run the same high voltage to the fpcm, as really we would only be using the fpcm for the negative output to regulate fuel pump voltage and thus duty cycle. To achieve this, the fpcm will not need huge positive voltage, as long as I upgrade the negative output of fpcm to the pump to a minimum size of 12ag.

When you quoted me above, as follows:

Completely understand all of that as I did before. I know the positive output of the fpcm is not pwm. I also understand that its my choice whether to run direct to the pump or to the fpcm.

 

However, ( im sorry im honestly not nit picking here but trying to be clear) - again you've suggested to use the standard fpcm input power wire (from the factory fuel pump relay in the engine bay) to trigger the relay. If i was running the new high voltge output from the new relay to the fpcm then yes this would work.

 

Correct, actually that relay is under the dash on passenger side in the US, only the fuse is in the bay in the fuse block (JUST for Clarity sake)

 

But if im running the high voltage wire from new relay to the pump direct, then it wont work as the fpcm will still need a power input. In this case, do you mean to say that I should splice into this wire to trigger the relay (ie parallel circuit), such that the wire still continues to the fpcm but also supplies a feed through another wire to the relay? Won't this overload the circuit?

 

Correct, like I said before, some have run the wire from the battery to a distribution block. From the block run one wire to the FPCM (in place of the factory fuel pump relay low voltage lead) and also run a wire from the block to the relay which in turn would go to the pump. The reason for this is powering the FPCM with batt voltage instead of the voltage that was dropping through the car from the factory fuel pump relay.

 

You could also in theory, splice the "low voltage wire from the stock relay" and feed it to the new relay as the "on' signal and also feed it back to the FPCM (like the factory), but the output is going to be less if you choose to come off the module for the positive lead.

 

The way I see it is id like to run a large positive polarity wire from battery to new relay to the fuel pump. The relay would be triggered by the positive output wire that used to go to the fpcm?

 

 

 

Then I would run the negative from fpcm to the negative side of the fuel pump.

 

That way the fpcm is still receiving its factory power input (no change to wiring here), and the only difference is the fuel pump positive wire is now coming through a new relay feeding battery voltage.

 

yes that will work fine and is the way zorro did it on NASIOC. I If it were me though, I would increase the guage of the wire coming from the FPCM connector NEG, to the pump. The pins pop out of that connector and you can solder a new larger guage wire for the negative side. You honestly dont want to skimp on wire size here either. The STI wiring is larger on both the positive wire out of the module and the PWM wire (NEG) out of the module

 

This is what I said in my original post, but you and heiche asked why I'm trying to do it differently and it wouldn't work.

 

Guess we were not understanding what you were saying, Sorrry

 

Just trying to clarify if this would work and if so would I need a solid state relay or just a normal four pin mechanical relay

 

Sorry for the headaches

 

 

Mick [\QUOTE]

 

 

Whichever way I do it, I'm going to run a minimum 12ag negative wire from fpcm to negative side of fuel pump.

 

In terms of the new relay trigger, if I use the factory power wire to the fpcm, my plan was to unsheath some of the wire, twist and solder a new short length of wire from this to the relay, and that way use the factory wire to both trigger the new relay and send power to the fpcm.

 

 

dr20t if you are in AUS, I would def get the fuse from hkb like I posted earlier.

 

Already ordered one -

 

Thank you for the tip on this one.

 

Keen to have this all wrapped up today if possible.

 

Mick

Completely understand all of that as I did before. I know the positive output of the fpcm is not pwm. I also understand that its my choice whether to run direct to the pump or to the fpcm.

However, ( im sorry im honestly not nit picking here but trying to be clear) - again you've suggested to use the standard fpcm input power wire (from the factory fuel pump relay in the engine bay) to trigger the relay. If i was running the new high voltge output from the new relay to the fpcm then yes this would work.

But if im running the high voltage wire from new relay to the pump direct, then it wont work as the fpcm will still need a power input. In this case, do you mean to say that I should splice into this wire to trigger the relay (ie parallel circuit), such that the wire still continues to the fpcm but also supplies a feed through another wire to the relay? Won't this overload the circuit?

The way I see it is id like to run a large positive polarity wire from battery to new relay to the fuel pump. The relay would be triggered by the positive output wire from the fpcm (the one that used to go to the fuel pump positive side)

Then I would run the negative from fpcm to the negative side of the fuel pump.

That way the fpcm is still receiving its factory power input (no change to wiring here), and the only difference is the fuel pump positive wire is now coming through a new relay feeding battery voltage.

This is what I said in my original post, but you and heiche asked why I'm trying to do it differently and it wouldn't work.

Just trying to clarify if this would work and if so would I need a solid state relay or just a normal four pin mechanical relay

Sorry for the headaches

Mick

Ok I'm going to really sound like a douche but i will still ask for the sake of clarity:

Scooby this question is directed at you: are you suggesting I use a normal four pin mechanical relay, or a solid state relay?

If normal mechanical one, and if I'm using it to power the fuel pump directly (bypassing high voltage to the fpc) will this be able to cope with the pwm regulation that the fpc controller will be providing?

If solid state, then doesn't the solid state relay need to be triggered via the negative wire of the fpc module output. I.e - negative from fpc to negative /ground on input side of the solid state relay? The reason I ask is because my learnings have been that using a solid state relay to control a variable voltage (pwm modulation for example) will need to be switched via negative trigger. Is this how I would do it?

I'm also now confused because in post 493 above, you were referring to wiring the fuel pump directly from the new relay, and in doing so bypassing the high voltage through the fpc. Ie high battery voltage goes to fuel pump only and fpc gets whatever it would normally get from factory. However in posts 501 and 502 I think you're talking about running the fpc on the new high voltage - ie battery voltage will go through the fpc to the fuel pump.

Which one is the better option? I would have thought the first (ie battery positive wire to relay to fuel pump), in which case the first set of questions above remain pertinent.

*EDIT* - scrap the last two paragraphs - I know what you're saying now: because you have already wired your fpcm through a new relay and upgraded wiring, it will be easier to just upgrade your pos and neg wiring from fpcm to fuel pump and see what that does. If it gives you required voltage then perfect and no more stuffing around - if it doesn't, only then will you look to bypass high voltage through fpcm and instead go straight pos 10ag from the relay to fuel pump, triggered by pos from the fpcm wiring.

Thank you again

Mick

take it after the fpcm on its way to the pump.

Which is what I was intending on doing until I saw scoooby's post above, advising to use the original power wire from factory fuel pump relay that would normally go to the fpc, as the trigger wire for my new relay

Ok one more question - if I'm using the factory power wire (that originally powered the fpc module) to now switch the new fuel pump relay, how is the fpc module receiving any power?

Does it not need positive power in order to still regulate pwm through the fpc negative output wire to the negative side of the fuel pump?

This is the only missing piece of the puzzle for me.

Thanks sooby - again apologies for any confusion caused.

I actually thought you were looking to change the setup on kc's wagon after your initial findings (max of 13.2v at the pump if I recall correctly)

Will proceed with the install using the above setup tomorrow and report back with findings

Mick

Thanks frank

Gotcha - I think I referred to the wrong trigger wire in my first post (I now realize I need to use the power output side from the fpc to trigger the relay for the pump , correct?)

What about powering the fpc through direct wiring through a relay?

What are people's thoughts on this?

Should I run one 8ag wire from battery to boot (fused at the battery) to a distribution block, then two 10ag wires to power the fpc and fuel pump via two separate relays?

Correct output wire of FPCM will not control relay as heiche said.

 

 

You have to do it like many others have said and the many drawings in this thread.

 

The wire from the stock Fuel pump relay is used to trigger the new relay.

 

dr20t Why change it from what the pump manufacturers recommend?

 

See wiring diagram posted in this thread from Aeromotive but just keep you FPCM in place.

 

If you dont think the FPCM (sti or otherwise) can handle the current then I would just purchase the DCCDpro.com FPCM and be done.

Thanks Scooby - I think I was vague in my initial post. Not really looking to change anything other than where the direct 10ag wiring from the battery will go.

That is, instead of going to the fpc module via a relay, it would instead go to the walbro via a relay.

I thought this is what you suggested a few pages back based on what zorro did on nasioc?

In any case not looking to reinvent the wheel at all

I am comfortable that the fpc can handle the current draw and don't believe the hype about it being "only rated to 8 amps otherwise it will attack your families and steal your clothes and the world is gonna end".

In the unfounded and unforeseen off-chance that this is true and the fpc module fails, then I would look at alternatives. But thanks to the work of your and others on here, I don't see evidence of it nearly 2 years on.

Another thought that just occurred to me -

What about if i run two separate circuits using 10ag wiring from the battery to the fpc on one relay, and the same for the walbro pump through another relay?

My logic here being upgrading wiring and voltage handling of both the fpc and the pump independently? And in this way ensuring both circuits are protected from voltage drop??

Thanks again for all input

Mick

Hi all

2004 audm liberty GT here (legacy).

I have been running a walbro 460lph in tank on my completely stock wiring (except the walbro e85 compliant pigtail plug) for about 2 months now. Was a pain to get in the cradle but ended up having to double o-ring.

I have also changed fuel pump duty cycle on my rom to 0, 75 and 100 percent only (removed low flow) - this was done in the hope of ensuring sufficient voltage for the required fuel flow at high load.

Running ID2000's, e70, Sard FPR, braided fuel lines in engine bay with y block. From the spec sheets, the walbro 460 will draw 19 amps at 90 psi when receiving 13.5v. I am looking to run max boost of 29 psi with base pressure of 45 with vacuum. Allowing for say 5psi system losses, this means i will see total fuel pressure of 80 psi.

So for headroom, i will design the system on the assumption of 90 psi max. I am looking to ensure between 13.5-13.8v at the pump, and therefore allow 25 amp current to be catered for in my system.

After being on the dyno yesterday, fuel pressure was dropping at 24psi above 6000rpm at full load, causing lean out.

Obvious that stock wiring cannot handle draw / load. So the pump needs to be hard wired.

Thanks to this thread I sourced the 2006 Sti fpc module, today

I am keen on retaining fpc modulation for two reasons in this order of importance:

1. The walbro 460 flows a crap load of fuel at base pressure which means idle is hard to maintain. I will change my rom back to stock 0,33,66 and 100 % duty cycle. By regulating duty cycle down to 33% at low load, this will help reduce the huge amount of flow this pump provides.

2. Heating of the fuel causing efficiency issues

I have now replaced the fpc module with the Sti one. No noticeable difference

After reading every post on this thread and most of the links posted, I would like some direction as to whether the following setup will be ok.

Please do not suggest running hard wired 100% of the time by bypassing the fpc - I am not interested in doing this unless absolutely necessary which I don't believe it will be at this stage.

Before i go into the proposed setup, what are people's thoughts on the double o-ring I mentioned above? I don't believe this in itself will be causing the pressure drop, as I'm sure the voltage issue is more important. However interested (after reading doccrowley's experience) to hear if maybe this is exacerbating the issue??

1. I am going to run a 10 ag wire from the battery to a 30amp relay.

2. Will use the fpc module output trigger wire to trigger the relay, then run 10 ag B+ output from the relay directly to the walbro 460. Earths will be new to the relay and not shared.

3. Upgrade negative trigger wiring from fpc to fuel pump to 10 ag wiring. I will be drilling two holes in the top fuel pump metal cover to run the 10 ag wires directly into the pigtail plug on the walbro 460, insulating them with rubber grommets on the tank cover. This way I can avoid stepping down the wiring to the stock plug.

Based on a few people's earlier findings on this thread, I was thinking to also upgrade the fpc module factory B+ wiring to 10 or 12 ag from the battery (a separate one to the relay wiring in point 1. Above ). My thinking here is upgrading voltage/ current handling of the fpc module will be a good thing as evidenced by the tests completed by Scooby2.5 and others in this thread.

Another way to do this is run say 8ag wire from the battery to a distribution block in the boot, then take my two power feeds from here to the fpc module and the new dedicatee 30 amp fuel pump relay.

Seeking opinions on this before I go out and complete it.

Thank you to all who have contributed

Mick

Mate I'm really sorry for what you have been through - sounds like a real bad run

All the best with getting it sorted. Hopefully no more bad luck.

Mick

This is a little old but better late than never :

Event: Hi-Tech Oils Race 4 Real Wednesday

Location: Sydney Dragway

Date: 5th September 2012

Ambient Temp: 30C (87F)

Elevation: 70m above sea level (230ft)

Weather: Clear sky

Car: 2004 Subary Liberty GT Auto

Tuner: Matt (throttlehappy) from KiDo Tuning

Track info: 1/4 mile drag strip: http://sydneydragway.com.au/

Transmission: 5EAT

Peak Horse Power at RPM: 258kw atw (346whp)

Peak Torque at RPM: 580nm

Fuel: E-flex (E71)

Engine/Power Modifications: Unopened EJ20Y Quad AVCS 2.0l turbo with 195,000kms (120,000 miles), Garrett 2871 turbo, fmic, id1000 injectors, 3" tbe with single cat, misc other bolt ons..

Driveline Modifications: None - completely stock 5eat

Suspension Modifications: BC coilovers, f and r swaybar, cusco bracing

Other Modifications:

Like Rome_Sti on here, my car has issues shifting 1st to 2nd and 2nd to 3rd at wot on boost. This is due to running hks evc and thus not relying on ecu to control bpost, which means boost cant be tapered and thus boost at redline is too high for tcu conditions to allow tcu to shift.

The above engine combo has since been replaced with a new setup which I'm currently awaiting Rebuild of my 5eat to be able to retune properly and then run again. Aiming for 300 plus kw atw and thus hopefully low to mid 11's.

http://img35.imageshack.us/img35/1713/bhtc.jpg

Mick

^ yea the bushings life is the life of your car. but there is a maximum torque that the gears can deal with.

Hey frank

Putting my bushings in next week with my acme pinnacle kit

Great to see them holding up !

Question for you - once the centre diff breaks like that, is the rest of the transmission generally cactus or can you replace the centre diff planetaries in isolation?

Reason I ask is if I have the same problem in future, I'm hopeful of still retaining the rest of my built up 5eat. I'm assuming as long as no metal paricles find their way to the remainder of the servo pump assembly and front half then it should be ok???

When my centre diff broke on my old box (car was completely stock at the time), we ended up replacing the whole box (due to my ignorance at the time of 5eat's and the lack of knowledge on these boxes here in Australia, which thankfully I am having an influence on changing now).

Mick

Absolutely cannot wait for my rebuild stage 3 kit from kouki and climber

Really looking forward to turning boost up and cracking close to 500whp

I must commend these two gents on the amount of r&d and work they have put into this kit. For those unaware, these boxes are quite complex in comparison to your conventional automatic, and finding the correct clutches and frictions / steels that will suit what is trying to be achieved (more clutch packs for greater durability and strength), as well as finding a competent and willing machinist to allow the drums to take the maximum additional clutch packs - is no easy feat.

Hats off to these guys for their efforts which hopefully will allow the benefits to be reaped by the 5eat community

Mick