Thread: Running great, crappy mileage

Well, I´m running a GTi-R setup, with complete stock ECU, MAF upgraded fuel pump, Nismo FPR. Got an AEM wideband, and it reads 14.7-15.8 cruising, and 11.6-12.1 on WOT at 15psi.
Car runs great and very strong. but I am getting roughly 20mpg at highway cruising and well below 14 at city driving. I looked for leaks but found nothing.

What else could I watch for?

When swapping the motor, I changed all the hoses and the carbon canister.

By stock ECU, you mean the GTiR ECU, correct? If so that is pretty crappy. I normally get about 20 in the city and 23 on the highway. I was worried at first, but then after reading the GTi-R boards I realized that they nomally get about 20mpg, so I stoped worrying. But your's is pretty low.

Are you haevy on the gas? Does she idle fine? o2 sensor hooked up? Check for any random codes from the ECU?

Yes, I got the GTi-R stock ECU. O2 sensor is hooked and fine, I plug the Nissan Datascan every now and then and there is no problem. It idles fine, just a bit high, around 1000-1100. The only code I get constantly is knock sensor.

On GTIR Modifiers Club they told me it was normal and good to be running 1 bar boost.

how heavy are you on the throttle? how often are you going into full boost?

Fix the knock sensor. It's more then likely old and cracked. That should help out some. And do the "adjust Idle" dance and lower the idle to about 900.

PM me you email and I'll send you the FSM for the GTi-R. It will help you a ton with little things like this.

And yea, 1 bar is the norm for the Rs. We are all doing... damn peer presure. Though having a heavy foot would kill you mileage.

Thanks, I already got the FSM, is the one in two pdf files. Knock sensor seems good.. I´ll try to get it out to check it. I did the idle adjust dance and all I got was 1100... 950 with the A/C. The adjusting screw is all the way in.

I don´t use much the car actually. My business y 5 blocks from home, and the car shop y 5 blocks on the opposite way. I mainly use the car for traveling on highways. I mostly run at speed limit, cruising, just boosting ocassionally to pass slow cars. Yesterday when returning, I boosted 15psi just 4 or 5 times in 500 miles.