Fuel pump control module

[mwiener2]

OK, lets try this again.

 

 

Stock fuel pump = about 8amps

 

FPCM designed for about 8 amps. If you try to use more than that, the FPCM will die.

 

It's that simple. It doesn't matter if you run 1/0 wire to the FPCM, it will still burn up.

 

 

I run E85 and my actual HP is close to 450hp at the crank completely uncorrected. There is no reason a pump can't do 100% all the time.

 

 

The same company that has the Pump Controller I posted earlier should also be releasing a twin pump sending unit that fits our cars in the next few weeks.

Edited February 5, 2013 by mwiener2

[Scooby2.5]

So you know for certain that the FPCM circuitry is only rated at 8 amps in a 15 amp circuit?

[Scooby2.5]

i highly doubt it would be any kind of problem..

 

and yours is 43 - engine vacuum if its idling right ?

 

Yep set for factory 43 LBS

[KCwagon]

OK, lets try this again.

 

 

Stock fuel pump = about 8amps

 

FPCM designed for about 8 amps. If you try to use more than that, the FPCM will die.

 

It's that simple. It doesn't matter if you run 1/0 wire to the FPCM, it will still burn up.

 

 

I run E85 and my actual HP is close to 450hp at the crank completely uncorrected. There is no reason a pump can't do 100% all the time.

 

 

The same company that has the Pump Controller I posted earlier should also be releasing a twin pump sending unit that fits our cars in the next few weeks.

 

Are running 100% all the time with your Walbro ?

[frank_ster]

So you know for certain that the FPCM circuitry is only rated at 8 amps in a 15 amp circuit?

 

a 15 amp fuse will typically blow with continous draw of about 12 amps.

12 amps is 50% safety factor of 8 amps.

[frank_ster]

Yep set for factory 43 LBS

 

so at idle its running 35 psi. right ?

[Scooby2.5]

good god frank you trying to quiz me on with or without vacuum?

 

35 with vacuum 43 without

[Scooby2.5]

a 15 amp fuse will typically blow with continous draw of about 12 amps.

12 amps is 50% safety factor of 8 amps.

 

Correct but we dont know what the ACTUAL specs are of the FPCM.

 

Ive been running mine at whatever current draw an Aeromotive draws for over a year.

 

Many an STI I am sure have been doing the same thing and I am NOT saying this is the RIGHT thing to do.

 

Sure would like to have the specs on the FPCM

[mwiener2]

A current probe would need to be placed inline with the circuit. An amp clamp simply clamps around a wire and does not interfere with the operation of the circuit. An amp probe can change the electrical properties of the circuit you are trying to measure.

 

I know that most engineered things have overhead built into them. It's usually not more than 25% more than the greatest expected load.

 

Something fused at 20a may only draw 6a most of the time. It's fused at 20a because sometimes it may see a spike of 18a. You can't just assume because it has a larger fuse you can go run up against that limit.

 

 

Why do you need me to keep proving you are overloading the FPCM? They are failing on you!

[Scooby2.5]

I know what a current probe/amp clamp is weiner.

 

https://www.google.com/search?q=current+probe&hl=en&client=safari&tbo=u&rls=en&tbm=isch&source=univ&sa=X&ei=-5URUbejGcqd2QW_54DIBw&ved=0CGwQsAQ&biw=1438&bih=719

 

They are BASICALLY one and the same.

 

If you search current probe smart ass you will also come up with the clamp around the wire style.

 

Some call them tomatoes some call them tomaatoes

 

I do have a BS degree in Electricity and Electronics and work for Toshiba Medical on X-Ray, Vascular and CT.

http://www.medical.toshiba.com/products/vl/dual-plane/index.php

 

Been working on cars and building them since I was 15 and now I am 44.

 

NONE of us that I know of, have had problems with the STI modules that have used them, that were not BAD when we got them from someone used.

 

Ive NEVER had one fail, and Ive been running my setup with the STI FPCM for over a year.

 

When you find the specs on the STI FPCM be sure to let us know.

 

Maybe you could do a test for us with your AMP CLAMP and see how much current it takes to blow the module up.

[KCwagon]

Why do you need me to keep proving you are overloading the FPCM? They are failing on you!

 

Who are referring to ? I am not aware of anyone who has damaged their FPCM because of this wiring change.

[mwiener2]

So what's the problem here? If the FPCM is not failing, then it is working properly and there is no issue. Why are you guys messing with them then?

 

Bigger pumps require more current. If the system is not able to supply enough current, the voltage drops. You guys have recorded this.

 

You put in larger wire that can handle more current and you noted a smaller drop in voltage. Something was still bottle-necking. It was the stock FPCM.

 

You guys found that the STi module dropped less voltage and installed that, but still see a voltage drop. It's because the FPCM cannot handle the current you are trying to run through it.

 

You can:

1) re-engineer the Subaru FPCM

2) Bypass the FPCM and hardwire the pump with a relay

3) Find an aftermarket pump controller

 

 

#1 is a waste of time unless you can get Subaru to buy your new design

#2 is the solution since cars

#3 is the proper way to do it but you have to pay to play

[KCwagon]

Good God man....we are doing this so that our fuel pump voltage is 13.8 volts to the pump (modified) instead of 11.8 volts to the pump (unmodified) ... ultimately we are simply trying to HELP each other fix a flaw in the system... as opposed to broadcasting our vast knowledge of EVERYTHING having to do with ANYTHING.

[mwiener2]

Your not fixing it!

[Scooby2.5]

My car puts out 13.9 alt voltage I have 13.5 at the pump.

.4 drop over the whole circuit the same as an STI, that we measured to verify the issues in the first place.

 

And I haven't even changed the tiny ass wiring from the module to the pump yet (this weekend)

 

We corrected over a 2 volt drop

 

Really we didn't fix it?

 

Don't know about you guys but i put down 385 whp on E85 (read 30 percent more fuel)

And mine has been running like a top for over a year.

 

And no I am not going to buy your $300 controller, Ill give you 50 bucks for one though.

Edited February 6, 2013 by Scooby2.5

[frank_ster]

[Scooby2.5]

So what's the problem here? If the FPCM is not failing, then it is working properly and there is no issue. Why are you guys messing with them then?

 

I guess you didnt read the beginning of the thread either, frank can you let him know what he needs to do

[frank_ster]

i was thinking about how the fcpm works .. there must be a resistor that is a different size coming off the fet , if you guys could send me pics of each circuit boards.

 

you guys would probably only need to solder 1 tiny resistor on one spot to make it the same as the sti fpcm. litterally a 10 cent part. or i could modify your boards for half of what it costs for a sti one .. ?

[Scooby2.5]

We will send you the buggy STI one if you care to look at it

 

Let me make sure its Ok with KC

[frank_ster]

for the fear of getting referred to the begining of this thread but where is this module ? easy to get to ? i could pull mine off.

[Scooby2.5]

Wagon it's on the back left side, drivers side, of the car behind rear panel about where the rear fender well is

 

Not sure on sedan

 

Vacation Pics???

[KCwagon]

Your not fixing it!

 

Laughing, thinking about you arguing with inanimate objects.

Edited February 6, 2013 by KCwagon

[KCwagon]

And no I am not going to buy your $300 controller, Ill give you 50 bucks for one though.

 

I'll give you $45 and a warm cup of urine; with a band-aid taped over the top so it doesn't spill (too much)

Edited February 6, 2013 by KCwagon

[Aracheon]

Wagon it's on the back left side, drivers side, of the car behind rear panel about where the rear fender well is

 

Not sure on sedan

 

Vacation Pics???

 

 

 

It's in the same place on the sedan, in the trunk, driver's side.

[SeeeeeYa]

Took apart the bad STI module and I found this:http://i573.photobucket.com/albums/ss178/shoneal55esp/DSC00102_zps068e8015.jpg

 

It was full of tiny (dead) bugs that had eaten the plastic covering from the coil and had imbedded themselves on and under the circuit board, creating a mess inside the unit. I suspect the unit was stored improperly before I bought it....Surreal

 

I think I am going to try to clean the mess out with the sticky side of a Band-Aid....

 

Looking at this, I am amazed... one, it is a sealed box. If that weren't enough, and I can't see details well enough to be specific, there is relatively no heatsink!

 

As Scooby2.5, and others, know, the addition of the right heatsink can magnify current handling immensely. It would be easy, and would provide some insight into whether a larger heatsink would help, to monitor the interior temps of the FPCM under varying fuel demands. If it doesn't get hot it is probably OK. But if the power devices show a rapid and significant heat rise at maximum load then a large®, exposed, heatsink will/should make the circuit much more reliable. If there is anything semiconductors cannot tolerate, it is runaway heat.

 

However, given the complete list of Scooby2.5's mods being done, this would more apply to use with pumps drawing very high current... that is, more than 15 amps.

 

Some facts here seem nuts to me... like little fuel pumps that suck nearly 20 amps... through wiring any electrician would laugh at, connected by a variety of press-fit connectors, sitting in a fuel tank.

 

Do not run out of fuel.