DSMAddicted

Guys,
I have been observing a solid 10mpg loss at every single fillup since late December.

As you can see, everything is pretty much new:

Full JDM ITR swap was performed about 12 months ago.
Engine was swapped with new OEM components (timing belt, water pump, injectors serviced by cruzinperformance etc).

Brand new 11.5 gal Spectra gas tank upgrade (less than 1 yr old)
New Fuel Filter (about 6 months old)
Clean K&N
Chipped P28 with O2 elimination

All of the above was on the car when I was driving it around with good mileage (anywhere between low to high 30s mpg depending on driving).
I even drove it to West Virginia and got 42mpg on one fillup.

I track every single fillup with the "Mileage" application on Android (by Evan Charlton).

In December my dizzy died while I was installing new spark plugs (NGK 5555 PFR6G-11) new rotor+cap and new OEM wires. This happened the night before I was supposed to drive to Miami for Christmas break. Tom (B18C5-EH2) didn't hesitate pulling the dizzy from his immaculate Hatch and saved the trip for me (thanks again bud, I owe you).

I drove the car from Atlanta to Miami (with Tom's dizzy) and got super shitty mileage. I got the car tuned a week after in Miami, car ran great and put down good power (ran out of fuel actually, would have made more).

Shitty mileage continued. On the way to Atlanta, I made it a point to stay on the right lane and drove super slow for 700+ miles (took forever, it was really boring, but I had to do this "for science" - almost hypermiling) and the best mileage I got was 30mpg (no AC needed - and don't forget the 42mpg going to W. VA last year).

At this point the only thing I thought would have been that Tom's dizzy might have been the cause of this. After all, that's the only plausible variable and Tom's Hatch is not his daily - when he drives her is for fun, so I was sure he doesn't pay much attention to the mileage he gets on the Hatch (Tom, correct me if I am wrong). I asked Tom to keep an eye on his Hatch's mileage as I returned it to him and installed a brand new Richporter Technology distributor.

As you will guess, shitty mileage continued, so that excludes the dizzy as potential culprit.

What do you guys think I should check next?

Thanks for the brainstorming help.

-Walter

kyden

do you have any way to monitor afr?

Marvin1985

iTrader: (5)

could it be the change in gas from winter to summer? did you use the same gas station chain to fill up each time? IE shell?

speedooo

What are your driving conditions? Highway? City? The gas mixture is changed in winter months. Also the colder winter air decreases MPG.

DSMAddicted

I am pretty sure I can log it somehow. I just asked Kenny (Turbogixxer).

No, different stations from GA to FL. Limiting myself to the same 2-3 stations for the past 6+ weeks though.

A bit of both, but mostly highway. Regarding colder air... I've always noticed better mileage in winter due to not needing AC.

Marvin1985

iTrader: (5)

Tire wear/pressure? Different rims? Additional weight in car?

decon

um check injectors, fuel filters and your wires/plugs. Well that's where i would start if my MPG when to **** that bad.

DSMAddicted

Tires have plenty of thread, running HX wheels, usually run a few psi higher than recommended. Right now they're around 36 psi due to colder tarmac. Weight in car has not increased, all I have is a small 10" sub.

Thanks buddy, but did you read my original thread? They are all new.

speedooo

What about your air filter?

decon

I did and u have a 6 month old air filter and 12 months on the swap. But just because there new doesn't mean don't check them. But just my advice. GL man...

Texas4door

I wonder if using Tom's dizzy got the ECU in your car "into the habit" of using that particular one.
Try resetting the ECU and doing a complete idle re-learn with your new dizzy.
Tis worth a try.

DSMAddicted

Air filter is K&N. I cleaned it before driving down to Miami in December. Still looks new.

Interesting, I need to look more into this. Thanks for the heads up.