aminoskee

I had the car checked by my tuner on that "Thursday" and later we had a chat about the issue. The main problem was my lack of understanding on how larger injectors behave compared to smaller factory stock ones. Factory injectors are 440cc and I now have 1650cc injectors which are almost 4 times larger. The 1650cc injectors cannot be dialed down to match the flow rate of stock injectors at idle and naturally they'll spray more fuel at idle. It is just the way it is. Later I spoke to a few guys who run the same injectors and they all confirmed that their fuel consumption at idle is around 2.4 L/Hour which is what I see on my dash cluster at idle. The other thing that I noticed is that my average fuel economy is getting better as I drive the car more which is likely due to the ecu learning and adapting again. All adaptations were probably wiped out when the car was tuned. Initially When I picked the car up from my tuner right after the mods my fuel economy was around 24L/100km. Gradually it reduced to around 17 - 18L/100km and now I am getting 14 - 15 L/100km. I hope it gets even better over time. I get much better fuel economy on the freeway and often the instant fuel consumption is somewhere between 6 - 7 L/100km or slightly more depending on the road inclination.

@Puffwagon Called the tuner today and they didn't have time until Thursday. Me being me and very impatient, I decided to get a new O2 sensor from Fraud Stealership and installed it right away. Unfortunately it didn't fix the problem. Now the only difference is that the O2 sensor voltage signal rises to 1.0 volts and stays there at idle. However, it's more responsive whenever I push the accelerator pedal. Both LTFT and STFT respond like before. Generally stuck at zero and only change when I push the accelerator pedal. I don't know what to make of this. Could it be a fueling issue caused by wrong injector parameters in the ECU??? Or maybe the fuel pressure in the fuel rail is too high due to improper/wrong FPR pressure adjustment causing injectors to spray more fuel??? I also looked at fuel pulse width and it was 0.39 ms at idle according to FORScan. I'm don't know if it is too high for 1650cc injectors at idle???!!!

@Puffwagon I'll do that and will report back.

@Puffwagon I drove the car all week and on a few occasions had FORScan running and monitoring O2 sensor, STFT, LTFT, SPARKADV and Throttle Position. Usually at idle the O2 sensor voltage is stuck at around 0.96 volts with STFT and LTFT stuck at zero and SPARKADV averages around 5.5 degrees. Some other times at idle the the O2 sensor voltage is again stuck at around 0.96 volts with STFT ranging between 10% to 25%, LTFT stuck at zero and SPARKADV bouncing between 1 to 3.5 degrees. However, O2 sensor voltage, STFT and LTFT and SPARKADV change as I drive the car. O2 sensor voltage still wants to be around 0.96 volts even when the car is moving and only reduces when I push down the accelerator as if there is an inverse relationship between the O2 sensor voltage and Throttle Position.

I took the car out today and drove it around with FORScan running live and monitoring both O2 sensor and STFT. The O2 sensor live graph was mostly stuck at 0.92 volts and fluctuated slightly lower from time to time. The STFT was mostly stuck at zero and moved slightly whenever the O2 sensor reading fluctuated. The interesting thing is that the O2 sensor voltage drops below 0.92 volts whenever I press the accelerator a bit harder and wont change much during normal driving. I don't know what to make of this!!!! Also, I looked inside the engine bay and checked the O2 sensor and it looks pretty old and dirty. I guess the tuner used the old O2 sensor of the stock factory exhaust system.

Thanks Puffwagon, I'll check these and report back.

I actually connected the car to FORScan to have a look at O2 sensor reading and fuel trim (STFT) graphs and to my surprise the O2 sensor war stuck at 0.85 volts at idle and the STFT was stuck at zero. I think you are right and I suspect that they have tuned it this way to ignore the O2 sensor reading and fuel trimming. But why would they do this? I think they did not enter the correct injector data in to the PCM such as break-point, high and low slope and minimum pulse width for the new injectors. Well, at the moment the fuel economy readings on the dash cluster seems wrong and the only way I can get a rough estimate of the fuel economy is to check at the pump and see how much fuel goes in and how long I have traveled. Also, the fuel gauge on the dash cluster is not shown the correct reading since I picked the car up from the tuner. The gauge needle shows one notch less when the fuel tank is fuel. I'm not sure why its not working correctly. I guess either the fuel level sender is stuffed or the tuner has set it up like this in the PCM to ensure I never run the fuel tank dry.

The car is indeed a beast now 😎 Its very quick and aggressive when it comes on boost and fun to drive. I'll be paying a visit to my tuner very soon and hopefully we can rectify all of these issues.

I should add that the car is only tune on 98 octane fuel.

Hello everyone, I have been a long time reader of this forum and a first time poster. I have a 2011 FG xr6 Turbo which I purchased second hand back in 2013. I drove my car stock standard since purchase as a daily. However, recently I decided to modify it to get more power and enjoy the modified car experience. The car has the following mods: - Process west stage 3 intercooler - Process west race air-box kit with 4 inch turbo inlet - Process west dual entry billet fuel rail - Process west battery relocation kit - Process west fuel stage 2 fitting kit - Process West fuel anti-surge tank with twin Walbro 460 fuel pumps - Walbro 460 fuel pumps in the fuel tank - Bosch 1650cc flow matched fuel injectors (from Quickbitz) - ARP head studs - Crow cams valve springs - Garrett GTX3582R Gen 2 - xr6 turbo development 1.06 A/R ford rear housing with 45mm turbo-smart external waste-gate kit - Xforce full 4 inch turbo back system - Yellaterra 10mm billet flex plate - Gj driveline pro series tail-shaft - IMS diff hat - Shockworks coilovers The car was tuned using PCMtec and produced about 430 rwkw on a mainline chassis dyno. well, the car drives well and is perfectly derivable. However, the fuel economy is terrible even when normally driving the car around (like a grandma). The car runs very rich at idle even after it reaches normal operating temperature and the instant fuel economy on the cluster only goes as low as 2.4L/100km which used to be around 1.4 to 1.6L/100km before mods. Also the the engine rpm at idle is now increased to 700 rpm compared to roughly 550 rpm before mods. I was wondering what is causing this and should I even be worried? I would appreciate it if you guys can provide me with your valuable insights. Kind Regards, Amin