Fuel pump control module

bad front O2 sensor and split Oring on the fuel pump. My voltage from FPCM to fuel pump didn't have any voltage loss whatsoever.

 

Re-tune going on now on a Dynapack dyno after 28+hours of diagnosis time.

Hey Guys, I pulled my monthly learning view last night and I see some knock in the 4000-5800 range which I NEVER had before. IAM was at .875 I was data logging, and I pulled a tad of timing and richened up those cells but it still seems to have slight knock. I am thinking I am running out of fuel. I have DW740's and the Walbro. Any thoughts, possibly a voltage issue after the fuel pump module? I really have not started a diagnosis yet but I thought I would run this by everyone.

See if you can plug in a fuel pressure gauge to check and see if you are losing fuel pressure under WOT. It indicated a fuel delivery problem for me and was a simple split oring inside the basket.

Thanks, I did use the viton o ring but you never know. I wasn't even thinking of that!

 

I have a FP gauge ready to go on today, thanks man!

Interesting that Aeromotive wants you to rewire basically like we did on my car for the Stealth 340 pump due to current draw....

 

"The factory fuel pump wiring may not be sufficient to handle the current draw of the Aeromotive 340 Stealth pump. To achieve the advertised flow at pressure, the use of an aftermarket wiring kit such as Aeromotive P/N 16301, including 10-gauge wire and a direct alternator supply point, is required."

 

http://aeromotiveinc.com/wp-content/uploads/2012/02/11140_11141_11142.pdf

 

We basically wired mine like the diagram in these install instructions but I don't think we ran a heavier gauge wire from the Control module to the pump which is a fairly short distance.

So we had the wiring from the stock fuel pump relay "turning on" the relay we added with a wire from the battery so power could come straight from the battery to the module.

 

The only thing not shown in the diagram is the Control module but its the same concept.

Instead of our fuel pump feed wire going from the stock relay to the module and then out of the module to the pump ours goes to a relay that has battery voltage, and then the battery voltage out of the new relay to the control module and then out of the module to the pump.

 

We spliced into the feed from the stock relay to the module, ran the power from the stock feed to a new relay and then to ground.

 

The other side of our new relay has battery power coming direct from battery and the other side feeding the module.

 

Basically just like the Aeromotive diagrams with the module in-between the pump and the voltage feed.

 

 

 

Here is another drawing in their 16301 kit they sell for doing this....

 

http://aeromotiveinc.com/wp-content/uploads/2009/12/16301.pdf

Edited June 18, 2012 by Scooby2.5

I had to read that twice before I understood what you did. So since you only changed the input wire to the fuel pump control module, you are still getting a PWM signal to the pump, correct? I wonder if it would of helped to change the wire going to the pump. How did you wire the new lead to the controller? Di you solder it onto the board?

Sorry, sorta hard to describe, I changed it a bit to see if that helps.

 

Yes still getting PWM to the pump. I didn't want to run the pump 100% all the time.

 

I agree, a buddy of mine and I were discussing the wire from the controller to the pump and changing it, but it is a much shorter run.

 

I was going to check the voltage again coming out of the controller and at the pump and see if there was much of a voltage drop.

 

The STI module just plugs right into the stock wiring harness if I remember correctly.

 

So what we did was just cut the wire a few inches back from the connector and wired in the relay, and the larger wire coming off the relay with full batt voltage to the connector on the module.

 

I can't remember the color code so you will have to look at the schematic in the vacation pics.

Just make sure you are looking at a turbo car in the vacation pics as the wiring is a bit different I think for the non turbo. I do know there was more than one diagram.

 

It works really well as reported a few posts back and seems to provide pretty much full voltage to the pump.

Edited June 18, 2012 by Scooby2.5

Any advantage over using a boost a pump?

 

http://www.kennebell.net/KBWebsite/Accessories_pg/Boost%20A%20Pump/layouts/boostapump.htm

 

It activates only at full throttle or boost, so it doesn’t “bloat” or “overload” the fuel system at idle or cruise where full time pumps and extra fuel are not required. So, the fuel isn’t heated (gasoline begins to boil at 87°). No “cool can” is necessary. And it’s much easier to install (cut one wire) and more reliable than fuel pumps. And since the BAP is also a voltage regulator (exclusive kb) it helps prevent engine damage from low voltage/ reduced pump flow during electrical overload or failure. It will attempt to stabilize the pump voltage and maintain sufficient fuel flow.

Ok, I just got done installing the STI FPC in my wagon. A few things to note.

 

The stock Fuel Pump Controller is located in the rear DRIVER's side. I know this because I took out the interior of the passenger side thinking it was there and nothing.

 

The stock wiring going to the stock Fuel Pump Controller for the Legacy is pathetic. The main power coming from the fuel pump relay is about a 20 gauge wire. The ground is the same. I was lucky enough on getting the wiring harness and hanger from he STI to compare. The main power, ground, and fuel pump power/ground wires are at least 12-14 gauge wire on the STI harness. That is a huge difference compared to the legacy. I wonder if just changing the wiring going to FPC would resolve a lot of issues. I already had the car apart so I went ahead and re-wired everything and stuck the STI FPC in. I ran 10 gauge power/ground to the FPC by soldering them onto the pins in the harness. I also ran new power and ground to the pump but only used 14 gauge wire because the wires in the tank are 16 gauge so there is really no gain by going any bigger. I now have 14+ volts at startup going to the pump.

Sorry integroid I thought I included that in a previous post about the module being on the drivers side but I guess I didn't.

I did the same thing as you, thought it was on the passenger side and then had to tear out the drivers side to find it.

 

Im glad you changed the wire from the module to the pump. We didn't do that and it looks like you are getting even more than I did. I was getting around 13.5v

 

Just FYI from an earlier post, you definitely need to change the module as we ran new wire to the stock module and still could only get 12.5

 

I may have to add in the the run from the module to the pump

Edited June 24, 2012 by Scooby2.5

Ok, I just got done installing the STI FPC in my wagon. A few things to note.

 

The stock Fuel Pump Controller is located in the rear DRIVER's side. I know this because I took out the interior of the passenger side thinking it was there and nothing.

 

The stock wiring going to the stock Fuel Pump Controller for the Legacy is pathetic. The main power coming from the fuel pump relay is about a 20 gauge wire. The ground is the same. I was lucky enough on getting the wiring harness and hanger from he STI to compare. The main power, ground, and fuel pump power/ground wires are at least 12-14 gauge wire on the STI harness. That is a huge difference compared to the legacy. I wonder if just changing the wiring going to FPC would resolve a lot of issues. I already had the car apart so I went ahead and re-wired everything and stuck the STI FPC in. I ran 10 gauge power/ground to the FPC by soldering them onto the pins in the harness. I also ran new power and ground to the pump but only used 14 gauge wire because the wires in the tank are 16 gauge so there is really no gain by going any bigger. I now have 14+ volts at startup going to the pump.

 

I will confirm that the wire gauge is different between the STI FPCM and the LGT FPCM. The legacy wiring being visibly a smaller gauge. Based on some other posts, the factory wiring from the FPCM to the pump itself does not drop voltage, probably because of the length of the wire (guess). Thanks to Scooby2.5 for helping me get mine wired up correctly. I will try to get a reading today for voltage on mine (wired like Scooby2.5 w/ an STI FPCM)

P/N for the STI FPCM and it's a direct repacement correct? Scanned twice, but my eyes are failing me.

"I am sending him a Fuel Pump Controller part number 22750AA010 that I picked up on NASIOC for $45."

 

I picked mine up on ebay for $40 with the bracket and wiring harness. I would suggest finding one that comes with the harness so you can pull the pins out and solder your own wires onto them. The pins from the STI will hold a bigger gauge wire than the the one from the legacy.

Based on some other posts, the factory wiring from the FPCM to the pump itself does not drop voltage, probably because of the length of the wire (guess).

 

 

Yeah, I didnt think it would and the wires were actually a thicker gauge going to the pump than the main power/ground for the FPCM. Go figure. I just figured since I had the harness apart and I was already pulling pins out of the harness, I might as well solder up two more pins and run the wires. It really only took me an extra 5 minutes.

 

Thanks Scooby2.5 for the initial findings. I went through two motors before we figured out the voltage problem going to the pump:(

 

PS- you dont need the wiring schematics for the FPCM. It is labeled on the bottom which wire does what. Just remember "E" = Earth Ground:)

It is interesting that you are getting 14 volts. The most we ever would get was 13.5

Could be due to the gauge of wire we used from the battery.

It would be interesting to measure coming out of the module and at the pump to see if there is in fact a drop across the wire going from the module to the pump.

 

At any rate most fuel pumps are tested at 13.5 volts

And I actually took the pins out of the harness and soldered the 10 gauge wire directly onto the pin instead of crimping a new wire to the existing wire off the harness. So there is no step down in the gauge of wire like what you did and it is a true 10 gauge power/ground to the FPCM. It is 14 volts out of the module and at the pump.

 

I forgot to mention I have 4 gauge wire going to my trunk for my stereo system that is connected to a 1.5 farad capacitor. I tied the power source to the relay from the capacitor. I dont know if that would make any difference but I know it will help clean up the power some.

My alternator voltage is only 13.5-13.8 so that is probably part of it as well.

Strange, I wonder why my alternator voltage is always above 14 volts? I am sure that is the reason...I dont see what else would be different between our setups. Maybe my Fluke Meter needs to be re-calibrated. It is like 10+ years old:)

My fluke gets calibrated once per year for work. My VBG1 says 13.8 as does my Escort Radar detector.

You just have a really good alternator. Mine has 180K on it.

 

13.8-14.8 is normal

They do it to reduce the heating of the fuel and evaporative emissions. In a nutshell, the pump will run in 3 modes: 1/3 at idle or no load, 2/3 at low load and 100% at high load. There is ABSOLUTELY NO REASON AND NO BENEFIT to running the pump 100% at all times.

 

..Therefore, my Walbro showing 33% at idle and 67% at load is normal? Just checking.

That is normal. At WOT you should also be seeing 100%.

THANK YOU, THANK YOU, THANK YOU for this thread starting at post #42!!!! Scooby2.5 your work on this is unbelievably helpful.

 

Got a call from my tuner today saying he was having troubles with my car. Said my injectors were maxed out on e85 (ID1000's and DW65c), but other parts of the system were telling him he had room to go. He said it seemed like the pump was not giving "it's all" so to speak. I remembered this thread and sent it to him. So now I have to get the module and discuss all the fun wiring that needs to be done.

Edited July 19, 2012 by coldsubycz

I know this might be a lot to ask and might be stupid sounding to all of you very intelligent people, but would it be possible for someone to draw out a diagram of this "new" setup?? The Aeromotive diagrams were helpful to better understand all this, but a more specific diagram would be extremely helpful to my visual mind. Adding details like what gauge wire, the wire from the battery, etc.

Cold, the harness is actually labeled on what does what. The only two wires you need to be concerned about are the B+ and E. B+ needs to go to the relay and earth is ground. Both need thicker gauge wire. Personally, I would take the pins out of the harness and solder new thicker gauge wire directly onto the pins. I hope this diagram of the Relay helps. The 12V fan wire should go to the B+ on the FPC.

 

http://www.titantalk.com/forums/attachments/titan-general-discussion/78244d1240275985-looking-10-amps-under-hood-relaywiring.jpg

^ What "fan" does this refer to in the diagram above and where is this relay located?

 

And "B"+ and "E" are actual terminals on the FPCM?

 

Apologies for my confusion. Trying to plan my upgrade and want to make sure I get this correct when I install my DW65C.