Thread: Bad gas mileage? Why!?

Well there you go, my point was even if the fuel pump can suck it in, it wont be any use in injectors. But since even the fuel pump can't use it (and if you have a walbro it will burn up), fumes are useless and wasteful.

I'm tempted to take the line coming from the green cap (the one with tirestem valve), and putting a one way valve on it and attaching it to the intake manifold. But the problem is it will always have vacuum while the car is running (until boost of course). Which might be a bad thing, maybe it will help the fuel tank? I'll try it out later

Yea. I'm going to find out my idling issue now too. cause here is what it does. When I warm it up, and drive around for about 5-10mins and come to a stop, it idles so perfect. Then drive a little more and come to a stop, then it idles high around 1k-1.2k. It doesn't fluctuate or anything. Just goes from perfect idle to high idle, depending how much I drive the car. My air fuel ratios are 14.6-15.0 when it high idles, but its perfect at 15.4-15.7 when its idling normal like it should be. Ever since it started to high idle like that, thats when I noticed bad gas mileage.

hey guys I didnt wanna make another gas mileage thread about this so I was wondering if any of you knew what exactly the gas mileage hit is from using a walbro 255 with the stock fpr?, because I just put my turbo nx back to stock for smog and filled the tank, I got 160 miles for a whole tank!! yet it runs great I can do a big peelout with my azenis still, could anything cause this except a fuel leak? My timing is at 17 and I pulled my fuel rail and nothing leaks it all is seated good. I'm about to change all my fuel lines. Or maybe should I get an fpr? I dont even have a fuel pressure gauge to check it with :/

ok guys, I noticed something this morning while warming up my car, my a/f ratios were rich as hell. It was staying at 10.8 and would not go lean as it warmed up like it yesturday and before. Then after my car warmed up it stayed at 13.2. It was litterally staying there. This was the first time I saw it happened. Before when its warming up its between 14.1-15.7. It goes lean when it warms up but this time it didn't.

Then when I started to drive to work, I noticed its flucuating between 11.1-13.2, crusing. I know I have a 4 bar fuel program and I was told from JWT the car will run rich for awhile and if I go before it warms up the car will jerk because of it running rich. Before it crusies at 14.7-15.1. I thought, ok, well this is probably why I'm killing gas. My tank was half when this happened, and going to work, 3miles from my house, it went down a little pass the half mark, which I just noticed it does this once in awhile, so maybe I should monitor my a/f ratios more when I warm up my car cause I think thats why I'm killing gas at idle.Like I said before, I get excellent gas mileage on the highway, but around the city, 15mpgs suck balls. So, I gotta figure out what the hell is going on with this gas mileage problem. I'm going to check my turbo manifold bolts to make sure nothing is loose since I know a small exhuast leak can mess with a/f ratios and kill gas.

If you're using the stock fpr, even having a 255 pump, your running stock fuel pressure. At least thats what I know. But, I get the exact same mileage as you do and my car runs awesome as well. What is your esitmate for highway mpgs?