Return-less or Return style fuel system: Which would you choose?

[bigdubz]

Hey Everyone,
My name is Andrew, my father Tom and I are building a mk4 roadster from a complete kit that we started in September.

So far we've got a 2003 Mach1 motor and ECM, and we're trying to decide how to fuel it. Dad picked up a return style (fox and sn95) pickup and pump for the fox-style tank that comes with the kit.

We now know that the motor is setup for the return-less system, and we're debating whether to sell the tank and purchase the complete return-less setup (CCRM/FPDM/99-04tank-pump) or get a new set of fuel rails and regulator to go return style?

We do not have a factory harness to diet, so we'll be purchasing either an RJM Injections or Telorvek setup.

If it were you, which setup would you prefer?

Thanks very much,

Andrew
~Son of Negoti8r

[d42davis]

Since the ECM is tuned for a returnless fuel system, I elected to change the F5 tank for a pulled Mustang tank and pump. Since the fuel filler inlet hole is larger, for the SS filler pipe, I had the Mustang tank modified with the larger inlet. I too am using a Telorvek system with no issues.
(I believe there are quite a few parameters in the ECM which have to be modified to change the operation to a return system.)
DD

[bigdubz]

Thanks for the reply.

I think that the ECM calibration is the heart of the choice.

Does anyone know definitively whether or not a 2003 ECM can be setup for a return system, how much work is involved, or if it even matters?

[Art Cuesta]

There are quite a few PCM parameters involved to correctly 'tune' a 4.6 returnless style fuel system when converted to a return style fuel system.

You would want it to go on a dyno with a good tuner to get it right. The problem if you don't tune it is possible leaning out of the air/fuel mixture to the cylinders and something 'bad' happening because your PCM is not 'dialed in' to the new fuel system it may not be able to keep the engine from going lean at some point.

The problem with converting is your disabling the FRPT (Fuel Rail Pressure Transducer) and the FPDM (Fuel Pump Driver Module) in the PCM and you have to recalibrate that PCM to work with your new return style fuel system. This info has come to me over time from working with guys who have experience with converting these returnless style 4.6's to Aeromotive or similar aftermarket fuel pumps - these setups usually require a fuel pressure regulator at the fuel rail and even different fuel rails depending or your particulars.

The key here is to do your research first before you buy anything.

Art

[bigdubz]

Thanks very much for your input Art, that kind of expertise is exactly what I was looking for.
Your point about research is right on. Fortunately a newer style tank assembly is easy to come by, and we'll have a nice set of parts to sell to help cover it.

So help me out with one last thing, we have the engine and ECM, we still need
Tank/pump
Fdpm
Ccrm
Telorvek system

Did I leave anything out?

[jcurti2]

I would guess your engine has the fuel rail pressure sensor on it, if not you will need it. You will need some way to connect to the CCRM and FPDM. You may be able to get the plugs from RJM Injection. If you want to do some more research before you decide, look at the '03/'04 Cobra Forum on modularfords.com. There are a few posts on what guys have done to switch to return style and tuning to make it work. Either way will work well when tuned correctly but several of the high horsepower guys switched to return. I think the high HP guys have seen FPDM failures that cost them engines.

Good luck with your choice.

[shelbyranger]

I love my return fuel system. Easy install and my tuner says its a breeze to tune plus will support alot my power if you ever upgrade to forced induction down the road. If you need any info let me know I can tell you how and what you need.

[Art Cuesta]

I'm not a expert on Telorvek from Detail Zone. My understanding is you build it from the controller panel and supplied wires and connectors they include in their harness kit and they work with you initially as I do to define what you need and then supply you with a version of their kit that addresses your build requirements. I see the PCM connector in their website ad so I assume since you need the CCRM and FPDM they also supply the wiring and connectors for those modules in the kit.

It appears they have some capacity to reprogram the PCM's for returnless or return style fuel systems - I recommend you contact them for the best information on what you need
or what you don't need for your particular setup with their Telorvek system.

But to answer your question if your Telorvek system is setup as a direct replacement for a stock 04 Mach I then you need the PCM, CCRM, FPDM and don't forget the Inertia (fuel cut off) switch. Another thing to ask about is the Data Link Connector / OBD II port wiring so you can connect to a diagnostic scanner.

Along with contacting Detail Zone there are builder's here on the forum who have used this system and their experience is what you want to hear. Hopefully they'll chime in about the details or you might want to start a new thread seeking advice from builders who used the Telorvek system.

Good luck with you and your dad's build!

Art

[thepink]

Art raised some really good points on things for you to consider. Speaking to the folks at The Detail Zone is key and they will advise you based on the parts that you have. Since I've just completed an Telorvek installation let me mention a few more.

Evaporative Emisstions hardware: Since you don't have a donor you don't have this. You can pick up most of the items at a junk yard or from a donor. You can live without it but this will effect the flash for the computer and the tank plumbing.

EGR: I'm guessing you have this but if you change your exhuast headers you will have to decide if you are going to keep it or flash it out. Having EGR can actually positively effect fuel economy so it's not all bad.

Tank and pump: As you have noted the returnless uses a different tank and pump. Some guys get a used one from a junk yard. Some of these same folks have found that the pump doesn't work when they try to start the car. If you research the forum you will find that these pumps don't like to sit around and not work. I went with a new tank and pump. The new tank is not that expensive and I was going to put a new pump in anyway.

CCRM: You probably don't have one since you don't have a donor. Not to worry. The Telorvek can handle this chore for you. On my unit it has a relay for the fuel pump and the radiator fan.

Inertia switch: Mine came with the complete kit.

FPDM: You will need one. I got mine from the junk yard and it worked fine.

And don't forget Max at Chapman Ford. Very helpful and good deals on genuine Ford parts.

Keep asking questions if you get stuck.

Mark

[bigdubz]

Thanks again Art and Mark, excellent advice.

I'll be calling up The Detail Zone Monday morning to get this plan together.

Andrew

[Art Cuesta]

I just want to second the motion for Max at Chapman Ford. Max has been around Ford and FFR for a long time and his knowledge and resourcefulness has helped me out more than once, not to mention I've found his pricing very hard to beat....

Art

[zschicago]

I chose the simple less complex route. Return style with Breeze setup. Easy to install. Went with the new Aeromotive 340 in tank pump. Using the telorvek panel. Since I supercharged the car I like be able to adjust fuel pressure. Works great..

[PGreenSVT]

Do some reading over on modularfords.com. A lot of the big power supercharged guys switch to returnless. That's the way I would go. You could also pick up a 96 or 97 Cobra ECM and run that as they were returnless and will handle the Mach 1 motor easily.

[Blown04stang]

Originally Posted by shelbyranger

I love my return fuel system. Easy install and my tuner says its a breeze to tune plus will support alot my power if you ever upgrade to forced induction down the road. If you need any info let me know I can tell you how and what you need.

I have a question about the return style system. I keep going through fuel rail pressure sensors and I was thinking about converting to the return style but I have some tuning concerns and like a little more info before I'd go that route