Astroc2002 Posted June 14, 2009 Share Posted June 14, 2009 (edited) At most I'm getting 238 miles max on a full tank with mid-grade. Anybody got any ideas as to why its giving my such lousy mileage as compared to other Pathfinders with the VG30E? Mind you the motor is fresh by only four years and so is the Transmission. So please give me some input as to why my rebuilt engine is doing this. Edited June 14, 2009 by Astroc2002 Link to comment Share on other sites More sharing options...
OldSlowReliable Posted June 14, 2009 Share Posted June 14, 2009 i find with mine atleast, that there is always a big gap....either im on the highway getting 23, or im driving around getting 15.....not so much inbetween If you don't have cruise control that could play into it Theres so many factors that its impossible to just say 'this is why' unless there is genuinely a problem like your leaking gas by the gallon... Link to comment Share on other sites More sharing options...
Soccerstudd5 Posted June 14, 2009 Share Posted June 14, 2009 When I had my 94, I wondered the same thing. I couldn't get more then 250 or 260 on a tank of gas. Never figured mine out either, so I'd be interested to see what you can discover. Sucks though when everyone else on here talks about getting better mpg Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 14, 2009 Author Share Posted June 14, 2009 When I had my 94, I wondered the same thing. I couldn't get more then 250 or 260 on a tank of gas. Never figured mine out either, so I'd be interested to see what you can discover. Sucks though when everyone else on here talks about getting better mpg Well it's nice to know I'm not the only one trying to figure this out. Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 14, 2009 Author Share Posted June 14, 2009 Tires, gears,driving style,there are a LOT of different factors To narrow it down I'm running stock 4.10 gears, 235/75R15 Yokohama HT-S Tires on stock OEM Aluminum Wheels, a Jim Wolf Cold Air Intake, new fuel injectors from rebuild, Doug Thorley Ceramic Coated Headers and a Flowmaster Two-Chamber Cat-Back Exhaust that is 2.5" piping from the headers back. Granted the gear ratio is a little on the low side so it might be part of it. Link to comment Share on other sites More sharing options...
MY1PATH Posted June 14, 2009 Share Posted June 14, 2009 running a bigger coil made an MPG improvement for me, It also burned my transistor becase it was too hot(55k volts vs stock 28k?). But an oem 240z coil (32k?) runs off the same transitor and may net some impovement. I don't know if the 300zx coil is hotter or not. I went back to the stock coil @ the same time I installed and electric fan. Since my MPG stayed the same I possitive the electric fan provided the same increase in MPG as the Coil had previously. Keep a good tune up, plugs wires, cap, rotor timing. Seafoam may or may not help depending on how much then engine may have needed it. The thorelys helped waste gass when I first got them but now that I'm over the thrill and not as heavy on the gass I think they have iproved MPG. Link to comment Share on other sites More sharing options...
OldSlowReliable Posted June 14, 2009 Share Posted June 14, 2009 i think the reason some of us get decent mpg, is cause...well...they are SLOW... I know that i personally drive totally different between the pathy and my malibu, simply because its an old slow truck, and it doesn't like it to get pushed hard... Maybe cause you had yours rebuilt, its getting more power, and therefore getting worse mileage? Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 14, 2009 Author Share Posted June 14, 2009 i think the reason some of us get decent mpg, is cause...well...they are SLOW...I know that i personally drive totally different between the pathy and my malibu, simply because its an old slow truck, and it doesn't like it to get pushed hard... Maybe cause you had yours rebuilt, its getting more power, and therefore getting worse mileage? That's true, but I'm going still talk it over with the mechanic who rebuilt the engine and see if the fuel mixture could be too rich, because I know when its warming up it has a nasty smell of fuel coming from both engine bay and the tail pipe. Almost to the point that there's excess fuel not being burned in the cylinders, how ever I have yet to have a back fire. Don't know. Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 14, 2009 Author Share Posted June 14, 2009 running a bigger coil made an MPG improvement for me, It also burned my transistor becase it was too hot(55k volts vs stock 28k?). But an oem 240z coil (32k?) runs off the same transitor and may net some impovement. I don't know if the 300zx coil is hotter or not. I went back to the stock coil @ the same time I installed and electric fan. Since my MPG stayed the same I possitive the electric fan provided the same increase in MPG as the Coil had previously. Keep a good tune up, plugs wires, cap, rotor timing. Seafoam may or may not help depending on how much then engine may have needed it. The thorelys helped waste gass when I first got them but now that I'm over the thrill and not as heavy on the gass I think they have iproved MPG. Well at one point I did have Nology ProFire M70 Ignition Coil (note do not get one do to poor design), but I had to remove it because one you have to cut the stock ignition wire from the clip to the stock coil to use them on the Nology Ignition Coil, two upon doing so resulted in frying the ignition coil wires and my O2 Sensor was blown out thanx to the ECU running a trouble shoot to find the Ignition, by doing that it pumped more fuel out of the injectors for a split second and upon igniting it also blow a hole in my Catalytic Converter. So yeah, don't do that no more. I might consider getting an MSD Ignition Coil Part No. 8228, even though it's meant for a Dodge I've heard others have used it in Pathfinders. Link to comment Share on other sites More sharing options...
MY1PATH Posted June 14, 2009 Share Posted June 14, 2009 Maybe cause you had yours rebuilt, its getting more power, and therefore getting worse mileage? I am in the school of thought that some power improvements; rebuilds, mild cams, headders & displacement increase (not turbos, agressive cams, injectors, nos etc) can go either way with mpg. If it has more power and you use more power it gets worse but if it has more power and you don't then it does not have to work as hard to acheve the same speeds as an unmodified engine. This is how a full bolt on N/A 5.7L LS1(my buddies) Can get 27 mpg on the higway and maybe about 11 if he spends a weeked @ the drag strip. And stock I belive those #'s were more like 23 & 14. ... I might consider getting an MSD Ignition Coil Part No. 8228, even though it's meant for a Dodge I've heard others have used it in Pathfinders. 8222 is the coil MSD specifically reccomened me for the pathfinder @ 45k volts it may be a little hot for the transistor unless you use their resistor card(which they reccomended). but I'm going to get the 8222 coil when I get my MSD igition box so no card will be needed. then my mpg should go back up again. Link to comment Share on other sites More sharing options...
diveobx Posted June 15, 2009 Share Posted June 15, 2009 The MPG is directly related to the use of the throttle. Going over 65 makes the gas go away much faster... Most of my pathy use is slow and local and the mileage is OK if there isn't too much stop n go and she rarely sees the high speed interstate. I do know that driving on the beach in low really can use the gas! However, I just did a 6 hour trip on the interstate and the first tank disappeared as I was driving fast. I tanked up and had to drive at slower speed due to road conditons and it got better mileage. I don't think the Pathy was really built to be an econo box but to take you almost anywhere you need to go, so I don't expect to get the MPG. Tune it up, keep the tires inflated properly and watch the use of the right foot is the best you can do. Link to comment Share on other sites More sharing options...
MY1PATH Posted June 15, 2009 Share Posted June 15, 2009 The MPG is directly related to the use of the throttle. Going over 65 makes the gas go away much faster... going 75-80+ down to cali (3-4k rpm for hours) I still got 17.5-18.5 mpg. It also seems to leak (or burn) oil when running that high rpm for prolonged periods of time. so what I may have saved in gass I spent in oil. lol Link to comment Share on other sites More sharing options...
adamzan Posted June 15, 2009 Share Posted June 15, 2009 (edited) I drove down to brantford a month ago, doing 120 km/h (75mph) most of the way and got just a hair under 23mpg. I had my 31's inflated to 35 psi, K&N freshly cleaned and oiled (properly), 4.6 gears, and a steady foot. Checked the oil before I left and before I left for home, it was the same. Driving around town I try to make it shift under 2800 rpm (autotragic) and drive the speed limit. I usually can get 18 around town. With my 235/75/15 tires my rpms were at 3000 at 120km/h but with the 31's its more like 2700. I'm pretty sure I get better mileage with my 31's than with my oem size Edited June 15, 2009 by adamzan Link to comment Share on other sites More sharing options...
nismothunder Posted June 16, 2009 Share Posted June 16, 2009 (edited) hell,I go 55 and my average tank is 19-20 Do you guys use syn-oil or dyno bones? Edited June 16, 2009 by nismothunder Link to comment Share on other sites More sharing options...
MY1PATH Posted June 16, 2009 Share Posted June 16, 2009 Do you guys use syn-oil or dyno bones? I use conventional or blended, full synthetic seems to leak on me. but I will prolly swich to full Synth after a re-build. Link to comment Share on other sites More sharing options...
87pathy Posted June 16, 2009 Share Posted June 16, 2009 its the oil companies paying off the auto manufacturers to de-tune the motors why does my 87 pathy with 350K miles on it get better milage than my 2000 frontier did new? something like 22 Vs 17 Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 16, 2009 Author Share Posted June 16, 2009 (edited) I am in the school of thought that some power improvements; rebuilds, mild cams, headders & displacement increase (not turbos, agressive cams, injectors, nos etc) can go either way with mpg. If it has more power and you use more power it gets worse but if it has more power and you don't then it does not have to work as hard to acheve the same speeds as an unmodified engine. This is how a full bolt on N/A 5.7L LS1(my buddies) Can get 27 mpg on the higway and maybe about 11 if he spends a weeked @ the drag strip. And stock I belive those #'s were more like 23 & 14.8222 is the coil MSD specifically reccomened me for the pathfinder @ 45k volts it may be a little hot for the transistor unless you use their resistor card(which they reccomended). but I'm going to get the 8222 coil when I get my MSD igition box so no card will be needed. then my mpg should go back up again. I had to deal with the same design with Nology's M70 Ignition and it fried my ignition wires, so 8222 is the same thing. But if you look at the 8228 Dodge Late Model while running at 40k volts it will be a direct plug-n-play unit while bolt up without any problems. But I just sent a message to MSD Ignition to confirm a problem free issue with 8228 coil. Nology M70 MSD Ignition 8222 MSD Ignition 8228 Which would people go with without cutting the stock Ignition wires, not being a punk, but hey its obvious and its a simple question. Edited June 17, 2009 by Astroc2002 Link to comment Share on other sites More sharing options...
OldSlowReliable Posted June 17, 2009 Share Posted June 17, 2009 on the train of thought of 87pathy, my drivers ed teacher owned a really old old car off the factory back in the day, he was getting 40mpg with a 4L v6 or something close to that, and they took it to the dealer to get it looked @, and they recalled the carb, and then he got 18mpg @ best... Its a scam. Ill be making the exact same trek tomorrow, so ill def keep a close eye on my mpg for ya Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 18, 2009 Author Share Posted June 18, 2009 on the train of thought of 87pathy, my drivers ed teacher owned a really old old car off the factory back in the day, he was getting 40mpg with a 4L v6 or something close to that, and they took it to the dealer to get it looked @, and they recalled the carb, and then he got 18mpg @ best... Its a scam.Ill be making the exact same trek tomorrow, so ill def keep a close eye on my mpg for ya Thanx yeah keep up to date. Link to comment Share on other sites More sharing options...
darkestskydiver Posted June 18, 2009 Share Posted June 18, 2009 i have a 90 pathy running 33's, stock pipes with a flowmaster and a k&n cone filter. i do not drive on the highway just around town and off road. i average around 280 a tank and have managed to sqeeze out an amazing 325 on one tank. but when i do travel i usualy can get aroun 300 per tank on the highway. :02: Link to comment Share on other sites More sharing options...
beavis0076 Posted June 18, 2009 Share Posted June 18, 2009 Just to add to the fun here.. are your sure you are almost out of gas when you are checking your mileage? I thought I was getting around the same mileage as you until I decided to see how far I could push it. My gauge said I was empty, but on fill ups I was only getting in 15 gallons. I still had 5 gallons in the tank when I thought I was almost out. Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 20, 2009 Author Share Posted June 20, 2009 Just to add to the fun here.. are your sure you are almost out of gas when you are checking your mileage? I thought I was getting around the same mileage as you until I decided to see how far I could push it. My gauge said I was empty, but on fill ups I was only getting in 15 gallons. I still had 5 gallons in the tank when I thought I was almost out. Yes, I was running on fumes when it reads under the empty line and when I fill it up from that point I put in between 16.8 Gallons or 17.5 Gallons. Now I'm not clear as of what size my fuel tank is, as far as I know it's a 15 or 16.5 Gallon Tank. Link to comment Share on other sites More sharing options...
nismothunder Posted June 20, 2009 Share Posted June 20, 2009 Its gotta be a 20 and a half gallon tank then if your putting 16.5 in it.They came in two sizes...15 and 20 5/8 gallons. Link to comment Share on other sites More sharing options...
adamzan Posted June 20, 2009 Share Posted June 20, 2009 It's a 21.1 gallon or 80 litre tank. Read your manual. Link to comment Share on other sites More sharing options...
Astroc2002 Posted June 22, 2009 Author Share Posted June 22, 2009 Its gotta be a 20 and a half gallon tank then if your putting 16.5 in it.They came in two sizes...15 and 20 5/8 gallons. That's a big tank for such a small truck, I think your right about it being 20 5/8 gallon tank... kinda weird size but what ever. Link to comment Share on other sites More sharing options...
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