No Fuel At High Rpm's

joshw0000 · Sep 29, 2014

Hey guys, I've got a '07 GT Mustang w/ BBK ceramic long headers, BBK shorty X pipes, Corsa exhaust, and a Stage 2 Roush supercharger ( http://www.roushperformance.com/parts/Ford-Mustang-Supercharger-2005-2009.html). I'm not the original owner so beside an Exceddy clutch, Hurst short shifter, and 3.55 gears, I don't believe this car has any other (performance) mods.

When I down shift and tach it to about 4,000 RPM's or just accelerate hard in general, the car is not getting gas and sputters. I'm getting about 15.5-16 MPG average (and I'm not typically driving it hard) so fuel is going somewhere. Always use 93 octane. Using the tune by a local Roush dealer who sold and installed the kit.

Any suggestions on where my fuel shortage is or what's causing it to sputter at high RPM's? I'm not a mechanic so feel free to explain in detail. Thanks for any input! I hope it's something simple.

timjimmy · Sep 29, 2014

How long have you had the modifications?

joshw0000 · Sep 29, 2014

The headers and exhaust have been on the car for several years. The supercharger and clutch were installed last March. I bought the car a few months ago. The original owner traded in on a 2014 Roush. I got his information (or rather gave mine) through a local dealer so I was able to meet him a couple months ago. He filled me in on the history of the car and sold me the tuner he was using.

timjimmy · Sep 29, 2014

Depending on the tuner, you should be able to data log the car's operation. If you can track the fuel rate and voltage to the pump, it should give you a better idea of what is actually happening, which will help figure out why it is happening. Also, examine the fuel lines and make sure nothing has been crushed or pinched. Using a wiring diagram, trace the fuel pump wiring harness, checking for damaged wires and cleaning grounds. When was the last time the fuel filter was changed? Is the car using the factory pump?

joshw0000 · Sep 29, 2014

timjimmy said:
Depending on the tuner, you should be able to data log the car's operation. If you can track the fuel rate and voltage to the pump, it should give you a better idea of what is actually happening, which will help figure out why it is happening. Also, examine the fuel lines and make sure nothing has been crushed or pinched. Using a wiring diagram, trace the fuel pump wiring harness, checking for damaged wires and cleaning grounds. When was the last time the fuel filter was changed? Is the car using the factory pump?

I honestly can't answer any of that. The kit was supposed to come with an upgraded fuel pump as part of the "GT500 Fuel System". I assume that also came with cold plugs, a new fuel filter, etc but I haven't personally checked.

I think I'm going to put it in the shop this weekend and have it looked over. Thanks for your feedback!

dcarlson · Oct 1, 2014

joshw0000 said:
I honestly can't answer any of that. The kit was supposed to come with an upgraded fuel pump as part of the "GT500 Fuel System

The GT500 fuel pump system adds a second FPDM (Fuel Pump Driver module). Look in the trunk in the spar tire well for two black boxes with wiring running forward towards the back seat where the fuel pump connections are. If you only have one FPDM, you don't have a true GT500 fuel pump system.

You need to get that car datalogged, as suggested above, to find out what is really going on. Running that car in boost without enough fuel can destroy and engine VERY quickly.

joshw0000 · Oct 1, 2014

dcarlson said:
The GT500 fuel pump system adds a second FPDM (Fuel Pump Driver module). Look in the trunk in the spar tire well for two black boxes with wiring running forward towards the back seat where the fuel pump connections are. If you only have one FPDM, you don't have a true GT500 fuel pump system.

You need to get that car datalogged, as suggested above, to find out what is really going on. Running that car in boost without enough fuel can destroy and engine VERY quickly.

Thanks for the info! I just checked and I do have 2 of them.

I hate to pay what Roush is going to charge, but I think I need to have them look at it.

joshw0000 · Oct 2, 2014

I've got an appointment with Roush next week. I'll just continue to drive in lower RPM's until I can get this fixed

joshw0000 · Oct 8, 2014

I just heard from Roush. Apparently my local Ford dealer had in fact overwritten my custom tune. When I flashed the Roush tune back to it, it was installing only the header tune as the Roush tune had been written to the ECU only, not my tuner.

The Roush dealer is going to re-flash the Roush tune and my header tune. All of this will be written to my tuner. According to Roush if the Ford dealership ever updates my ECU again, I'll always be able to install a full Roush tune again.

I can't wait to get my car back! It hasn't known that it was supercharged or been getting enough fuel for a couple months now. She'll have 475 HP when I pick her up tonight!

timjimmy · Oct 8, 2014

I'm always very specific about not flashing the ecu on the rare occasions that the car is at the dealership.

Noobz347 · Oct 8, 2014

joshw0000 said:
I just heard from Roush. Apparently my local Ford dealer had in fact overwritten my custom tune. When I flashed the Roush tune back to it, it was installing only the header tune as the Roush tune had been written to the ECU only, not my tuner.

The Roush dealer is going to re-flash the Roush tune and my header tune. All of this will be written to my tuner. According to Roush if the Ford dealership ever updates my ECU again, I'll always be able to install a full Roush tune again.

I can't wait to get my car back! It hasn't known that it was supercharged or been getting enough fuel for a couple months now. She'll have 475 HP when I pick her up tonight!

Looking forward to hearing back. Short vid would be nice too.

joshw0000 · Oct 8, 2014

timjimmy said:
I'm always very specific about not flashing the ecu on the rare occasions that the car is at the dealership.

This happened when I first bought it. The day I got home it threw a check engine and check charging system light. Long story short, they had my car for over a week (2 separate work orders). I thought I had just got used to the power but I always knew in the back of my head something wasn't right.

A couple weeks later I called to ask about not getting fuel (or getting too much). They suggested I call Roush. Roush put me in touch with the original owner who sold me the tuner (and some other stock parts).

I'll put painters tape over the port from now on with a note not to update ECU.

Almost there. My wife and I left work early....I'm getting excited!

joshw0000 · Oct 8, 2014

Flashed ECU back to Roush. He said it was running really rich with the stock flash. I'll get the dyno sheets tomorrow but I'm told it's making 477 RWHP. That's after backing it down a little.

I opened it up on the way home. Now she screams at 3K+ rpms! So glad to have it running right now!

I'll try to get a short video this weekend.

joshw0000 · Oct 8, 2014

Ordered one of these just in case the message doesn't get to the next Ford technician.

No Fuel At High Rpm's

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