Why is my mileage so low?

GRGT1994

New Member
Sep 22, 2004
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I just filled up. And I am getting less than 14 miles per gallon now (like 13.5). WTF? See my sig for mods.

I have the timing dialed in as suggested by Trickflow and Anderson Ford. It runs like a beast now. But still I get this horrible mileage. And I read these posts from others with HCI setups saying they get close to 20 mpg (maybe they guys never corrected their speedos for aftermarket gears???).

Anyone else getting really bad mileage? Any ideas what might be my issue, or what I should look for?
 
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I look at your sig and say...you wanna play, you gotta pay....more power means more petro....no way around it.... :(
I mean look at the mods and your gears....Those ain't MPG gears.... :D

I'll throw this out for what its worth....you running an oil separator?? I added one and gained some MPG right off....mine was woofing alot of oil and it musta had an affect on my milage..I emptied the separator 3 times in 1200 miles....so it was drinking its share of two stoke mix shall we say...
I havent even thrown a timing light or nada to it since pulling it outta storage this Spring, just drove it...Chit I got 2 YR old NGKs' in it....only thing it got this year has been 2 oil changes...
If i drive it calmly, 18-20...if i drive it normal...prolly 16...
 
Well, if nothing else you could check some obvious things. Make sure you air filter is clean, tire pressure, how's your alignment? Maybe you need to replace an 02 sensor. I corrected all of these things on my car and picked up some mpgs. They add up.
 
I actually just got 25.22 mpg on the interstate, from Minneapolis to Fargo while doing 75mph. Not too shabby. I'm shooting for getting 26 or 27, hopefully 28 when I take a trip a little later in october on some 55mph highways.
 
Ever think that your speedo may be off. Tire size as well as gears throw of the speedo. Taller the tire, the faster it spins at a given speed. So that could throw of you mpg. Try this, go on the interstate and watch your speedo. Start at one mile marker and see how much your mileage goes up by the next mile marker. Mine only does .7 per mile marker. So, this means, assuming that the mile markers are correct, that my speedo is reading 30% less than what it is supposed to. I am running 275/55/17 tires which are bigger than stock. So you can see that while i only get around 20ish on the highway, with windows up doing 70 with cruise control, im closer to 26.
 
meyers2211 said:
My smog pump is clamped shut, what is the difference b/t that and an egr

Smog and EGR have no relation. Two completely seperate systems, one should not effect the other. :shrug:

Smog pumps air into the catalytic converters to help burn the leftover fuel in the exhaust.

EGR takes exhaust gas and recirculates it through the engine to help cool combustion temperatures (exhaust gas is roughly 600* vs. combustion temps of 2000*).

Two seperate systems.
 
chirs said:
Ever think that your speedo may be off.
Thanks for the thread revival Chirs. My speedo is reading fewer miles than I am driving. I tested in on highway mile markers (10 miles for accuracy) after I installed my Speed Cal. But it reads within 1% to 2% of dead on.

I know the 4.10's aren't gonna get me into the Sierra Club, but when I read posts like the one from John getting 20 mpg and Zero Signal getting 25 or more I wonder WTF? Are those guys talking about their Prius, or are their speedo's off.