nipper Posted February 24, 2012 Share Posted February 24, 2012 It's weird. I have never seen a MPG hit on winter fuel (more of an urbane myth as it is winter that drops it) and east coast ethanol. When i get inot the fly over states I have to keep away from it at all costs as it makes blu run like garbage and eat up the fuel. Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 25, 2012 Author Share Posted February 25, 2012 I'm testing one more theory to see if it's a major contributor to the fuel usage... Seeing how much correlation there is between my right foot and fuel economy. Quote Link to comment Share on other sites More sharing options...
nipper Posted February 25, 2012 Share Posted February 25, 2012 I'm testing one more theory to see if it's a major contributor to the fuel usage... Seeing how much correlation there is between my right foot and fuel economy. And weather will also. Quote Link to comment Share on other sites More sharing options...
LokeDawgg Posted February 25, 2012 Share Posted February 25, 2012 Got 22 mpg on my last tank. Just cleaned the MAF with denatured alcohol, and will report mileage findings on next fill-up. I'm pretty sure I need struts, trailing-arm bearings, and tires, so my mileage may not be the best! :-p Quote Link to comment Share on other sites More sharing options...
Markus56 Posted February 26, 2012 Share Posted February 26, 2012 Ethanol makes all cars built before 07 or so run like crap. it also eats away at everything like fuel lines, o-rings, and pressure regulators. I know it made my 91 lego get about 15 mpg. and it ate through my fuel lines! Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 26, 2012 Author Share Posted February 26, 2012 Just got my ElmScan 5 and OBDWiz software. Will report what sensors are doing. Need to do it badly on my Montero sport as well. Hopefully this combo is the ticket, as it was only $30 and would be a valuable tool in anyone's asernal; if they work. Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 26, 2012 Author Share Posted February 26, 2012 Well I logged all of my engine readings while driving to work at a refresh rate of 270 snapshots per minute. Was able to determine that my upstream o2 is running up to .95v with an average of .51v and my downstream was indicating a max of .88v and an average of .32v. On the freeway, my average upstream was about .75v which indicates a fairly rich condition. Average fuel consumption was about 22.7mpg according to the realtime data, with my engine load at an average of 25% of max. My average throttle position was 15% of max; so my right foot is not the culprit. I suppose it's time to start hunting for parasitic vacuum leaks and and pre cat exhaust leaks. Quote Link to comment Share on other sites More sharing options...
Del Gue Posted February 28, 2012 Share Posted February 28, 2012 What does the exhaust smell like? Rich, burns your eyes? If so, check/replace the MAF with a lesser milage one from the Junkyard for about $40. I had a similar issue with my '95 Outback EJ22. 100 miles would be Half tank Also, check the IAC. These were the two major culprits with my extremely poor MPG, 16MPG with a Flat-4 Engine = BS! I thought I might be able to get some needed info out of this entire thread. What is the IAC and where is it located? Thanks. Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 29, 2012 Author Share Posted February 29, 2012 So I determined that if I keep the car cruising at about 72mph (3100 rpm) my realtime mpg is 22 on flat, and if I keep it at 68mph (2750rpm) my realtime is 26mpg on flat. Clearly, there's some sort of trigger around 3000rpm that richens the crap out of the fuel mixture. This is also with a snowboard rack and 205/65/15 snow tires at 34psi. Next tank I will pull the roof rack and put my street tires back on and see what I can achieve. I found no signs of vac leaks and my catch cans are pretty dry which tells me that the blowby problem is minor. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted February 29, 2012 Share Posted February 29, 2012 What is the "FPR?" Fuel Pressure Regulator. Quote Link to comment Share on other sites More sharing options...
sparky11 Posted February 29, 2012 Share Posted February 29, 2012 At 72 mph with the drag of the board rack and soft sticky snows, you are probably in open loop most of the time due to the load on engine. I've driven with similar setup while watching data stream on scan tool. The mileage, speed, load correlation is easy to see. Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 29, 2012 Author Share Posted February 29, 2012 My effective load rating rarely goes over 23% except when going up the 2 larger hills on the freeway; rack/snows or not. Interesting note, my Montero idles on start up at 54% load. Can't wait to get into diagnosing that beast... Quote Link to comment Share on other sites More sharing options...
sparky11 Posted February 29, 2012 Share Posted February 29, 2012 Your running a 2.5, I'm running a 2.2 and if I remember at 75 it shows 52% load and doesn't want to stay in closed loop. Yours should stay in closed loop at that low load. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 29, 2012 Share Posted February 29, 2012 Since you're reading rich exhaust, what happens if you induce a small vacuum leak? Quote Link to comment Share on other sites More sharing options...
Ricearu Posted February 29, 2012 Share Posted February 29, 2012 Your mileage will decrease as your speed goes past 60mph. My wife's legacy with 2.2 gets 26-28 if I drive 60mph to work, but if I drive 80mph, it gets 21. I was late to work today, and had traffic on the way home, so when I wasn't in traffic wasting gas, I was driving 80. Filled up again just today to see what repercussions it had on my tank. 20.68mpg. :-\ One's foot has a huge effect on MPG. and yeah the surf board rack will hurt areodnamics Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted February 29, 2012 Author Share Posted February 29, 2012 Your running a 2.5, I'm running a 2.2 and if I remember at 75 it shows 52% load and doesn't want to stay in closed loop. Yours should stay in closed loop at that low load. I'm still running a 2.2. Need to hurry up and get my 2.5 block done, huh? Since you're reading rich exhaust, what happens if you induce a small vacuum leak? When I cleaned my MAF, I accidentally bumped my cruise vacuum line off. Didn't have the scanner hooked up, but it ran like crap and tried to die at idle. Should I see what kind of readings I get with a vac leak? Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted March 4, 2012 Author Share Posted March 4, 2012 Put my street tires back on, removed my snowboard racks, and reset my ecu after doing a compression test. Got almost 25mpg realtime at 70mph. Interestingly though, when I started out, it was at 27 or 28mpg, and as I got closer to work, it dropped to 23 or 24; even when I slowed to 65. Compression was iffy also: 1 - 190 2 - 205 3 - 200 4 - 180 Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 5, 2012 Share Posted March 5, 2012 when I started out, it was at 27 or 28mpg, how did you figure this? Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted March 5, 2012 Author Share Posted March 5, 2012 how did you figure this? Running a laptop based datalogger with realtime MPG estimates. Running plots to attempt to see any direct relations between sensor voltages/mpg/rpms/etc... Quote Link to comment Share on other sites More sharing options...
cal_look_zero Posted March 6, 2012 Author Share Posted March 6, 2012 Welp, as of today (according to my data logger) I'm steadily at the upper end of 25mpg; which I'm totally happy with. Apparently the snow tires and roof rack caused enough rolling resistance/wind drag to drag 5mpg off my averages. Guess I'll just take 30 minutes to swap everything back on when I want to go ride. I'm still planning on replacing both o2 sensors as PM, when I put my new engine in though. I have to imagine 230k miles on sensors is probably well past their effective usage. Quote Link to comment Share on other sites More sharing options...
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