E85 Guys: ECU fuel pump control in a return system?

How does fuel pump control work in return system when using the factory ECU? Ive decided the next major mod for my Shelby will be a conversion to a return style fuel system to run E85 at the track and other performance oriented times.

Im looking at saving for this kit here from Lethal Performance:
http://www.lethalperformance.com/le...whp-triple-pump-return-style-fuel-system.html

The fuel pumps are not pulse width modulated like in the factory returnless system. The kit includes wiring to splice into the harness for the FPDMs, but the return fuel pumps are constant flow.

How does the Ford ECU not freak out when a return style setup and pumps are installed? Do the tuners turn off certain codes in the ECU when running a return system? Does the ECU not know any better as long as its programmed A/F parameters are met?

For my 07, all that really needed to be done was disable the fpdm codes. I did also change the fuel pump voltage table., and some of the injection pressure drop tables(mainly to reflect the constant fuel pressure of the return system), but the car would run without any tune changes(just throw codes). I believe the later years are more difficult to tune. Save yourself some headaches and get a Fore system.

The pressure is handled by the regulator instead of by the ECU/FRPS. You'll need a tune revision to have it run properly.

69b302 said:

For my 07, all that really needed to be done was disable the fpdm codes. I did also change the fuel pump voltage table., and some of the injection pressure drop tables(mainly to reflect the constant fuel pressure of the return system), but the car would run without any tune changes(just throw codes). I believe the later years are more difficult to tune. Save yourself some headaches and get a Fore system.

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X2!

I see, so essentially the tuner will disable the codes relating to fuel pump and pressure control and install custom parameters. The ECU logic will still "see" the "fault" of the FPDMs but not report it?

With my triple pump, Lund asked me to pull the signal from the FPDM1, and use a Hobbs pressure sensor, on the vacuum line, to engage pumps two and three.

Yes, I had error messages related to the FPDM, but once they were cleared, I've not seen anything since.


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All 3 of my pumps run full time. Hooked in to the first fpdm. The fc3 controller is super easy to hook up. Not much room for the regulator up front


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lexustech48 said:

I see, so essentially the tuner will disable the codes relating to fuel pump and pressure control and install custom parameters. The ECU logic will still "see" the "fault" of the FPDMs but not report it?

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Yes, this is how the early years work(07-09). A different PCM for 10-12, and then again for 13 and 14s if I recall correctly. Some of the later years require more tuning, but I have no direct experience. I would recommend you run a hobbs switch for pumps 2 and 3, as no reason to build that much heat and draw that much power for around town. I had battery charging issues, if the car idled alot, when running all the pumps full time.

I certainly appreciate all the replies gents!

Unfortunately i just found out due to STATE LAW in AZ, the max pump ethanol content is only E54...... Looks like wont be converting for E85 afterall.

^^ do it. Even at ~e50 mixes you will realize HUGE benefits over pump gasoline.

Turbo BMW guys swear by the E50 mix.

gimmie11s said:

^^ do it. Even at ~e50 mixes you will realize HUGE benefits over pump gasoline.

Turbo BMW guys swear by the E50 mix.

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I was gonna say the same thing. My brother is a Subaru guy and he was telling me this earlier this summer. A lot of those guys are running E50 and loving it. Still benefits to be had I suppose.

RBB said:

I was gonna say the same thing. My brother is a Subaru guy and he was telling me this earlier this summer. A lot of those guys are running E50 and loving it. Still benefits to be had I suppose.

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Does the car 'learn' the alcohol content or do you have to tune for each mix (E85 vs E50 etc) ?


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Dinosgt said:

Does the car 'learn' the alcohol content or do you have to tune for each mix (E85 vs E50 etc) ?


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He said Cobb makes a flex fuel kit with an ethanol sensor. It will adapt to whatever you put in the tank on the fly. Sounds pretty cool.

I vaguely recall seeing an article a while back that said AED was doing something similar for the newer Shelbys.

Only issue i see with Running E54 is that the car is going to be DUMPING e54 in to get to stoic. I believe the more fuel content in the Ethanol mix, the richer it has to run.

At that point, for me personally, its easier for me to tank up on Sunoco or VP 100 unleaded on the pump when I hit the strip.

I love AZ, but they truly have a bad performance fuel situation. 91 is the highest on pump and no E85 by law... smh lol. If I ever decide to move in the future (which I may) Ill be heading to the Automotive promised land of Texas.

Actually the opposite is true.

Less fuel will be used because of the higher gasoline content.

Hmmmm........

Serious question: On our GT500s, would a Kenne Bell Competition 21v boost a pump and ID 1050Xs be able to handle E50 in the factory returnless system?

That depends on how much power you want to make

ill be upgrading to a Trinity TVS possibly by the end of the year. Id realistically like to make 700-750 rwhp. 800 if its capable. E50 wouldnt be a DD fuel, id being using pump 91 and the VMP pulley hub system to get me to a safe boost.

My goal is to get into the low 10s consistantly. I dont want to cage my car and i dont street race, so having anything more honestly wpild be a waste.

I use an e30 tune on the wife's ST and it definitely has more power than an equally modified ST running only 91 or 93. We use an inline ethanol sensor and gauge to make sure we are within 2% ethanol content of the tune. I've been contemplating the same set up for the Shelby.

lexustech48 said:

ill be upgrading to a Trinity TVS possibly by the end of the year. Id realistically like to make 700-750 rwhp. 800 if its capable. E50 wouldnt be a DD fuel, id being using pump 91 and the VMP pulley hub system to get me to a safe boost.

My goal is to get into the low 10s consistantly. I dont want to cage my car and i dont street race, so having anything more honestly wpild be a waste.

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Same goal as me. Although i'll add i want to break 140mph.

I'll be buying my TVS end of summer... still undecided on the Trinity TVS/65mm TB combo from FRPP or go full retard and buy a Gen2R......cant wait!