Fuel pump control module

^cool. I think I'll stay at 90% if you are at 92% with a built motor.

I'll post up some numbers when I get them. But don't get to excited. The dyno I get tuned on is the lowest reading dyno in the country .

With the engine running, my 11 STi measures 13.89v at the B+ wire to the FPCM. It goes up slightly when idle is minimum.

Wires are properly sized per circuit. The FPCM itself is not visably a PCB, it is a smallish metal box.

At higher levels of power output I see 93% IDC during the summer. Not too bad. But in colder weather 100% IDC aren't uncommon. Oddly, but thankfully, even the rare 105-6% IDC in colder temps haven't caused my AFRs to change. The pumps performance, therefore, must be adequate (even if the injectors are marginal). I use 93 E10.

This thread is of fundamental importance to the forum's platform, and should be stickied. It may not have directly impacted my STi, but it gave me the same directions that will help others correct an important flaw that may mean all the difference.

Yep! Turned out that the first FPCM I bought was bunk. Bought a second replacement and the problems suddenly went away.

Sent from my ADR6400L using Tapatalk

Just out of curiosity if I end up doing this, would I need to get retuned right away? Or can I drive the car how it is, I'm trying to piece some needed parts before a retune in the spring.

I'll be switching back to my 91pump tune here in a few weeks from e85. I'll let you know what transpires. My tuner says I should have no issues, mabye run a little rich at worst. Before I say anything concrete I would like to make the switch and log.

Um... running 91pump on an E85 map?

My 91pump tune was done before I did the STI FPCM mod. I use an APv2 so this will be the first time I will be running my 91pump tune with the newly installed STI FPCM.

To clarify I will re-flash with my AP to my pump tune/map. I will not be putting 91 octane in my tank and running my e85 tune/map.

^ the variable speed pump is to save energy, the 2.5i models dont have it.

the pump can easily jump from 33% to 100% with out any problem.

larger pumps should have bigger wires.

there is two wires going to the pump. the positive is fed from the relay. the negative is pwm to give the pump variable speed.

you can easily ground the pump at the sending unit to prevent the pump from running at the slower speeds with out setting any trouble codes.

the pump running faster at higher engine rpm i doubt it would be the 110 amp altenator if there arn't any other obvious problems with the car. ie fans start and the car will die.

most car companies do the variable speed fuel pump. the earliest one i know of is 1997 buick regal gs and the grad prix gtp's that have a relay and resistor to make the pump run slower. often a problem with the resistor the cars would start then stall.

the subaru pwm method is much better and more efficient.

^ the variable speed pump is to save energy, the 2.5i models dont have it.

 

the pump can easily jump from 33% to 100% with out any problem.

 

larger pumps should have bigger wires.

 

 

there is two wires going to the pump. the positive is fed from the relay. the negative is pwm to give the pump variable speed.

you can easily ground the pump at the sending unit to prevent the pump from running at the slower speeds with out setting any trouble codes.

 

the pump running faster at higher engine rpm i doubt it would be the 110 amp altenator if there arn't any other obvious problems with the car. ie fans start and the car will die.

 

most car companies do the variable speed fuel pump. the earliest one i know of is 1997 buick regal gs and the grad prix gtp's that have a relay and resistor to make the pump run slower. often a problem with the resistor the cars would start then stall.

the subaru pwm method is much better and more efficient.

Frank ster is right on theory and wiring . But I differ about the pump providing fuel from 1 speed to another with no problem . When a pump starts and stops you have lock rotor amperage occur . This itself is a delay in pump speed increase and as we'll a drop in voltage. Both could be minor but they are there for sure. My reason for mention is another thread the guys are pulling their hair out about stuttering idle and engine at different rpms.I see that problem possibly being the result off the problems were talking about here . And the energy savings yes they are there but if you are monitoring your engine with graphs for high performance tunes The savings are not worth the trouble . Racing is not cheap. Or at least we could put a bypass switch to the speed control setup when we drive hard.

Frank ster is right on theory and wiring . But I differ about the pump providing fuel from 1 speed to another with no problem . When a pump starts and stops you have lock rotor amperage occur . This itself is a delay in pump speed increase and as we'll a drop in voltage. Both could be minor but they are there for sure. My reason for mention is another thread the guys are pulling their hair out about stuttering idle and engine at different rpms.I see that problem possibly being the result off the problems were talking about here . And the energy savings yes they are there but if you are monitoring your engine with graphs for high performance tunes The savings are not worth the trouble . Racing is not cheap. Or at least we could put a bypass switch to the speed control setup when we drive hard.

the pump does not stop when changing speeds. the only thing that could slow pump speed acceleration is its inertia of witch is has almost none.

and from the data logging i have done the ecm tells the pump to speed up to 100% if you sneeze on the throttle. has any one data logged fuel pressure when having these problems ?

You last few posters need to go back and read the whole thread.

It irratates me to no end when people obviously only read the last little bit in a thread and start posting theories and information that only clouds the FIX that has already been discussed in this thread from the beginning

A capacitor for the fuel pump

SubaruFirst no offense but you said it yourself, "but I'm not that knowledgable of the system just theory"

For those just joining, this problem had nothing to do with the stutter problem......

Start from the beginning and read the WHOLE THREAD! Honestly it wont take you that long!

You last few posters need to go back and read the whole thread.

 

It irratates me to no end when people obviously only read the last little bit in a thread and start posting theories and information that only clouds the FIX that has already been discussed in this thread from the beginning

 

A capacitor for the fuel pump

 

SubaruFirst no offense but you said it yourself, "but I'm not that knowledgable of the system just theory"

 

For those just joining, this problem had nothing to do with the stutter problem......

 

Start from the beginning and read the WHOLE THREAD! Honestly it wont take you that long!

Thank you. Thank you.

And the "stutter problem" has nothing to do with the pump either, BTW.

You last few posters need to go back and read the whole thread.

 

It irratates me to no end when people obviously only read the last little bit in a thread and start posting theories and information that only clouds the FIX that has already been discussed in this thread from the beginning

 

A capacitor for the fuel pump

 

SubaruFirst no offense but you said it yourself, "but I'm not that knowledgable of the system just theory"

 

For those just joining, this problem had nothing to do with the stutter problem......

 

 

Start from the beginning and read the WHOLE THREAD! Honestly it wont take you that long!

Ditto on this...

the pump does not stop when changing speeds. the only thing that could slow pump speed acceleration is its inertia of witch is has almost none.

and from the data logging i have done the ecm tells the pump to speed up to 100% if you sneeze on the throttle. has any one data logged fuel pressure when having these problems ?

Logged in the sense that I watched my fuel pressure gauge rise and then fall as I was doing pulls, yes. I believe I detailed this in an earlier post in this thread.

You last few posters need to go back and read the whole thread.

 

It irratates me to no end when people obviously only read the last little bit in a thread and start posting theories and information that only clouds the FIX that has already been discussed in this thread from the beginning

 

A capacitor for the fuel pump

 

SubaruFirst no offense but you said it yourself, "but I'm not that knowledgable of the system just theory"

 

For those just joining, this problem had nothing to do with the stutter problem......

 

Start from the beginning and read the WHOLE THREAD! Honestly it wont take you that long!

This. +1,000,000,000.

I have had no luck finding an STI FPCM for a decent price. Anyone ??

eBay is where I bought both of mine... around $40 a pop.