lunchindabox Posted January 19, 2009 Share Posted January 19, 2009 Ok, so here goes... Background: Bought this little automatic 4x4 R50 1.5 years ago with 102k miles. It needed some work so we had it done (waterpump, Tbelt, knock sensor). Down the road we got some suspensions issues and had those done too...Now has 112k miles and runs great. Enough power, no real leaks, no smoking, no sputtering, no loosing oil/coolant..ect Current issue: Currently I have codes P0440 and P1448 and from what I can tell, they are evap/emmisions related. I don't think this is the cause of the bad gas mileage but I am no pro. I cleared them 2 days ago and no SES lights yet. The light comes and goes as it pleases and we don't care until it is time for emmisions in Aug. I had low tire pressure on one tire, which shouldn't affect the mileage that much. It has recently been pretty cold in the DC area if that makes a difference. ....But to be honest, I never really pay attention to mpg until recently, last 3 fillups only had 12-13mpg. The truck is driven very little, mainly the ole ball and chain who drives it 2 miles to work or 2 miles to school 3-4 times weekly. I only drive it when I hookup the tow dolly and pull a car home about 2-3 times a month if that. Any suggestions on where to look or is this normal mileage for my driving habits and weather conditions... Thanks! Link to comment Share on other sites More sharing options...
laxman0324 Posted January 19, 2009 Share Posted January 19, 2009 I would guess it is because the engine never gets a chance to warm up so it is constantly running in open loop mode, dumping fuel into the engine and causing your mileage to suffer... Link to comment Share on other sites More sharing options...
silverlion Posted January 19, 2009 Share Posted January 19, 2009 I have the same mileage issue, about 12. It does a little better on the hwy but not much. I notice a decrease during the winter months. I lose about 30 -40 miles on a tank. I'm still trying to get enough dough for manual hubs. I have done the full tune up, no codes, tires full, etc. I even tried the K&N route to no avail. I just figure it's the SUV syndrome... Link to comment Share on other sites More sharing options...
laxman0324 Posted January 19, 2009 Share Posted January 19, 2009 Right up until I sold it I got 16 mpg with the hubs locked on my 97 around town, 18 on the highway...With them free I got 17 in the city, just over 20 on the highway, all with 31x10.50 tires... Link to comment Share on other sites More sharing options...
adamzan Posted January 19, 2009 Share Posted January 19, 2009 I get 16.5 in my 95 right now that is mixed between 15 minutes highway and 40 minutes of traffic every day. So I guess I'm doing ok.. When my cat was clogged I got CRAP mileage. Link to comment Share on other sites More sharing options...
XPLORx4 Posted January 20, 2009 Share Posted January 20, 2009 (edited) I would guess it is because the engine never gets a chance to warm up so it is constantly running in open loop mode, dumping fuel into the engine and causing your mileage to suffer... I'm going to agree with laxman on this one. If the truck sees mostly towing duty and 2-mile runs between cold-starts, you can expect pretty poor fuel economy. Engines and drivetrains don't run very efficiently until they reach operating temperature (which takes a lot longer in low ambient temps), and of course, towing doesn't help fuel economy much either. Edited January 20, 2009 by XPLORx4 Link to comment Share on other sites More sharing options...
180sx Posted January 20, 2009 Share Posted January 20, 2009 Conclusion: Driving Habbits. Link to comment Share on other sites More sharing options...
lunchindabox Posted January 20, 2009 Author Share Posted January 20, 2009 Conclusion: Driving Habbits. I drive like a grandma, but the ole ball and chain is a little tougher on the gas pedal. I was suspecting the short driving habits and truck never fully warming up to be the culprit but didn't want to suggest it so I could see what others came up with. I guess that is it. That and the fact that I thought the r50 was rated for higher mpg's, like 19 for combined city/hwy...but it is more like 15-16 so I am not doing as bad as I thought... But my needle hits below 3/4 mark and odometer only states 50 miles. Most of my other cars, the needle does not move until after it hits 50. Kinda depressing, but I know all machines are not built equal. Well, thanks all! Link to comment Share on other sites More sharing options...
Pezzy Posted January 20, 2009 Share Posted January 20, 2009 Not sure what the weather is like where you are, but the cooler winter weather also will take a bite out of your mileage. Link to comment Share on other sites More sharing options...
tekazgtr1984 Posted January 20, 2009 Share Posted January 20, 2009 Not sure what the weather is like where you are, but the cooler winter weather also will take a bite out of your mileage. X2 Weather plays a huge factor in gas mileage. I've noticed my mileage drop over the last couple months thanks to a wicked cold snap. It sucked.... Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted January 20, 2009 Share Posted January 20, 2009 I would guess it is because the engine never gets a chance to warm up so it is constantly running in open loop mode, dumping fuel into the engine and causing your mileage to suffer... x2 i have the same problem in my '87 in the winter, im getting around 9-10mpg it barely gets warm even when i let it warm up, and the tranny oil is thick as molasses this time of year. Link to comment Share on other sites More sharing options...
vengeful Posted January 20, 2009 Share Posted January 20, 2009 Currently I have codes P0440 and P1448 and from what I can tell, they are evap/emmisions related. I don't think this is the cause of the bad gas mileage but I am no pro. I cleared them 2 days ago and no SES lights yet. The light comes and goes as it pleases and we don't care until it is time for emmisions in Aug. I had low tire pressure on one tire, which shouldn't affect the mileage that much. It has recently been pretty cold in the DC area if that makes a difference. ....But to be honest, I never really pay attention to mpg until recently, last 3 fillups only had 12-13mpg. The truck is driven very little, mainly the ole ball and chain who drives it 2 miles to work or 2 miles to school 3-4 times weekly. I only drive it when I hookup the tow dolly and pull a car home about 2-3 times a month if that. Any suggestions on where to look or is this normal mileage for my driving habits and weather conditions... Thanks! With the recent cold here in DC, it's not surprising that your fuel economy has taken a bit of a hit. Even my Acura has suffered a bit. I only got 24.6mpg on the tank where it was 10 degrees out. LOL Also, as is said below, the 2 mile drives are KILLER on fuel economy. You'll use as much fuel in the first 2 miles of driving as you will in the next 4 once the engine warms and goes into closed loop. I'm going to agree with laxman on this one. If the truck sees mostly towing duty and 2-mile runs between cold-starts, you can expect pretty poor fuel economy. Engines and drivetrains don't run very efficiently until they reach operating temperature (which takes a lot longer in low ambient temps), and of course, towing doesn't help fuel economy much either. +1 Link to comment Share on other sites More sharing options...
Pezzy Posted January 20, 2009 Share Posted January 20, 2009 I only got 24.6mpg... BOO effing HOO! Dude, do you want to be banned? Link to comment Share on other sites More sharing options...
tekazgtr1984 Posted January 20, 2009 Share Posted January 20, 2009 BOO effing HOO! Dude, do you want to be banned? That's so mean... Yet gut-bustlingly high-larious! Link to comment Share on other sites More sharing options...
Alkorahil Posted January 20, 2009 Share Posted January 20, 2009 Currently I have codes P0440 and P1448 and from what I can tell, they are evap/emmisions related. I don't think this is the cause of the bad gas mileage but I am no pro. I cleared them 2 days ago and no SES lights yet. The light comes and goes as it pleases and we don't care until it is time for emmisions Thanks! P0440 is small evap leak. It is most likely caused by P1448 which is the canister control valve. Fix 1448 and 0440 should go away. Teh bad control valve will effect mileage. Link to comment Share on other sites More sharing options...
PDCCD Posted January 20, 2009 Share Posted January 20, 2009 Soo, wow, this seems so counter intuitive, but would letting the truck warm up before starting off help save gas for a short commute? I too drive only 3 miles to work, and my mileage is abysmal. Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted January 20, 2009 Share Posted January 20, 2009 Soo, wow, this seems so counter intuitive, but would letting the truck warm up before starting off help save gas for a short commute? I too drive only 3 miles to work, and my mileage is abysmal. IF you let it warm up all the way to 160 or what ever the temp is that the ECU switches to closed loop. or after the ecu cuts the fuel enrichment which is above a certain temp. you would have to look in a FSM to find out what those values are. Link to comment Share on other sites More sharing options...
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