The Kid Posted August 11, 2008 Share Posted August 11, 2008 hey guys I have a 93 and whenever i get gas, I take how many gallons I put in from E warning light and reset the TRIP and i see how many miles I got until the warning light comes back on again... with the last 3 experiments ive got an avg of 8-10 mpg and to me that sucks. I have driven my brothers ls 430 and my father's 97 and my friends 99 LS's and their efficiency is sooo much better than my 93. my friend has a 91 and is getting about 6-7 MPG SO what I wanna know is if all first gen owners get the same results or if im in a dire need of a tune up... if anyone has results lemme know!!! Quote Link to comment Share on other sites More sharing options...
Bali26 Posted August 11, 2008 Share Posted August 11, 2008 Thermostat. Then, sparks, wires, distributor caps etc. Use premium gas, full air in tires. Quote Link to comment Share on other sites More sharing options...
Captain Meeks Posted August 11, 2008 Share Posted August 11, 2008 Are you using premium gas? Is one question...and I would seriously check into a tuneup... I have a 94 and it gets on an average between 18 and 22 sometimes alil better depending... also the tank should be 22.5 gallon. The fuel light operates on a sensor so depending on when it lights up could be issue there,a few gallon could make a world of difference in the gas milage equation these days...but, I would check on plugs,wires,air filter...the whole shabang of a tuneup. There is a problem there somewhere at 8 to 10 miles to a gallon.. :( Quote Link to comment Share on other sites More sharing options...
Alexander the o.k. Posted August 11, 2008 Share Posted August 11, 2008 My 1992 ls400 has 255,000 miles and is way overdue for a tune up, and I get about 18-20 light-city, and 25-27 hwy. Are you experiencing any other drivability problems with the car? Symptoms? Make sure you are calculating correctly. Quote Link to comment Share on other sites More sharing options...
eatingupblacktop Posted August 11, 2008 Share Posted August 11, 2008 hey guys I have a 93 and whenever i get gas, I take how many gallons I put in from E warning light and reset the TRIPand i see how many miles I got until the warning light comes back on again... In addition to the good suggestions above, I would say you've prob got some dirty or malfunctioning sensors. For example, a bad O2, air/fuel sensor, or ECM could prevent the engine from going into a closed loop mode. Check your sensors and fuel trims. But what has me puzzled is why you would wait until the low fuel warning comes on before filling up? Read up on various posts dealing with low fuel levels to inform yourself of the unnecessary risks you're taking by doing this. Quote Link to comment Share on other sites More sharing options...
The Kid Posted August 12, 2008 Author Share Posted August 12, 2008 hey guys I have a 93 and whenever i get gas, I take how many gallons I put in from E warning light and reset the TRIPand i see how many miles I got until the warning light comes back on again... In addition to the good suggestions above, I would say you've prob got some dirty or malfunctioning sensors. For example, a bad O2, air/fuel sensor, or ECM could prevent the engine from going into a closed loop mode. Check your sensors and fuel trims. But what has me puzzled is why you would wait until the low fuel warning comes on before filling up? Read up on various posts dealing with low fuel levels to inform yourself of the unnecessary risks you're taking by doing this. well it was only 3 times I did the test and i only waited to the warning light came on because i knew definitely that was a marker for the end of the experiment. I know the catalytic consequences if you ride too low on E but as soon as the light came on I made sure to put gas... well thats the only way I could know that I was at the same fuel level for sure. but I am shocked at some of the mpg you guys are getting. i ALWAYS use premium gas in fear of engine problems that could occur if i use regular thats never a thought to use regular... when i bought this car it was in immaculate condition aside from the gas efficiency. i guess tune up is definitely what I need to do. out here in NYC its about 400 for a tune up... is there any better cost effieicent way to get better MPG? Quote Link to comment Share on other sites More sharing options...
Captain Meeks Posted August 12, 2008 Share Posted August 12, 2008 hey guys I have a 93 and whenever i get gas, I take how many gallons I put in from E warning light and reset the TRIPand i see how many miles I got until the warning light comes back on again... In addition to the good suggestions above, I would say you've prob got some dirty or malfunctioning sensors. For example, a bad O2, air/fuel sensor, or ECM could prevent the engine from going into a closed loop mode. Check your sensors and fuel trims. But what has me puzzled is why you would wait until the low fuel warning comes on before filling up? Read up on various posts dealing with low fuel levels to inform yourself of the unnecessary risks you're taking by doing this. well it was only 3 times I did the test and i only waited to the warning light came on because i knew definitely that was a marker for the end of the experiment. I know the catalytic consequences if you ride too low on E but as soon as the light came on I made sure to put gas... well thats the only way I could know that I was at the same fuel level for sure. but I am shocked at some of the mpg you guys are getting. i ALWAYS use premium gas in fear of engine problems that could occur if i use regular thats never a thought to use regular... when i bought this car it was in immaculate condition aside from the gas efficiency. i guess tune up is definitely what I need to do. out here in NYC its about 400 for a tune up... is there any better cost effieicent way to get better MPG? Not really kid..maint. and upkeep are the key to any cars survival. @ the rate you are burning fuel and at current prices the tuneup will pay for itself/ . Eatingup had a good point that I overlooked.. the 02 sensor and a few odds and ends couldnt hurt but a good mechanic will over view the car when he does a tuneup and if you explain the problem look over a few of the other options. At a tank of gas running around 80.00 look at it this way if you can double or better the mileage you are getting and turn four tanks of gas into eight..not a bad investment. Good luck Quote Link to comment Share on other sites More sharing options...
glenmore Posted August 12, 2008 Share Posted August 12, 2008 Generally I only get about 15-17 mpg in the city with a bit of highway driving so I barely get 300 miles from a tank of gas. Full highway driving, the mpg is better maybe in the low 20s. I have a 1990 LS400, about 160m. glenmore 1990 LS400 1991 300CE 2000 C280 Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted August 12, 2008 Share Posted August 12, 2008 Wow unless your calculations are completely off.... something is horribly wrong. I'd take all this advice to heart ASAP and get some maintenance done. Filters, fluids, ignition, thermostat. The most I've squeezed out of my 97 is 29.3mpg and there was much room for improvement. I've ordered new denso Iridium LL plugs to replace my cheapo NGK GP Platinums, and a new set of OEM wires to replace my 12 year old wires. So I'm going to break 30mpg highway SOMEDAY! It's my life goal! hahahahah Quote Link to comment Share on other sites More sharing options...
1993LexusLS400Rob Posted August 13, 2008 Share Posted August 13, 2008 I have a 93 and i get about 13-15 mpg (highway/street). I had a tune up done about 6 months ago. I use 87 octane though and I have since the car was new. Never had any problems with the lower octane. Quote Link to comment Share on other sites More sharing options...
SW03ES Posted August 13, 2008 Share Posted August 13, 2008 I think your problems with the lower octane are in the fuel economy arena, your figures are pretty low. If you calculate the difference in cost between regular and premium over the life of that car and look at the figures others are getting with the same car, I bet using regular has cost you a lot of money... Quote Link to comment Share on other sites More sharing options...
fisher972002 Posted August 13, 2008 Share Posted August 13, 2008 Hmm, somethin' wrong there My 1991 with 170K gets with a mix of hwy and in-town 20.94 MPG.. that is way off double check calc's.. Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted August 15, 2008 Share Posted August 15, 2008 Hmm, somethin' wrong thereMy 1991 with 170K gets with a mix of hwy and in-town 20.94 MPG.. that is way off double check calc's.. Thats almost EXACTLY what I get with my 1991 LS400 with 213K. Its mostly 20mpg in town... occasionally 21-22. With the A/C on though... its likes a lot more gas! :) Quote Link to comment Share on other sites More sharing options...
The Kid Posted August 17, 2008 Author Share Posted August 17, 2008 thanks for your input people. imma have to go get my car checked ASAP... I see you guys saying that i probably calculated my mileage wrong, but what i want to know is what methods did you guys use? maybe using yours will make my readings more accurate Quote Link to comment Share on other sites More sharing options...
IansLexus Posted August 18, 2008 Share Posted August 18, 2008 hey Kid, I would think my readings are SOMEWHAT similiar to yours. Well, at least not as high as most others. I get about 15.7-16.6 ALL town, and 19-20 ALL HWY (a/c off half the time, when a/c was off, windows were down), with 20" rims. My numbers too seem kind of low, too. I take 3 readings total for each (city and highway). I fill All the way up, until the gas pump clicks off, no higher. Immediately reset odo. Run my car down to the gas light, fill it back up and seee how much it took and what my odo is at. if it takes 19 gallons for 300 miles... 300/19= 15.7mpg. I think I need to get my car checked too! Quote Link to comment Share on other sites More sharing options...
IS400 Posted August 18, 2008 Share Posted August 18, 2008 thanks for your input people. imma have to go get my car checked ASAP...I see you guys saying that i probably calculated my mileage wrong, but what i want to know is what methods did you guys use? maybe using yours will make my readings more accurate This statement you made gets to the meat of the problem with your results. "I know the catalytic consequences if you ride too low on E but as soon as the light came on I made sure to put gas..." O.K. I know you probably intended to write 'catastrophic' instead of 'catalytic' but lets move on... To measure your mileage more accurately try this. Fill the car until the pump automatically clicks off. Do not add anymore. Period. Reset your trip computer to zero and drive away. Drive only in the city stop and go if that is what you want information on. Drive only on the highway if this is the data you need. Do not warm the car up at home during these trials and do not change the way you drive. When the car gets to around 50 miles or so (it really does not matter much, but it is a nice round number) on the trip computer go back to the same gas station and fill using the automatic stop method as described above and write down the exact gallons it took to get the pump to click off. Get the calculator out (or use the computer accessory) and divide the miles driven by the gallons used to fill the tank back up to full using the automatic click off method. (make sure to seat the nozzle fully each time and use the trigger stop so there is no human error.) Your math is most likely what is getting your result screwed up. Here is quote for you that I have always liked, that addresses the problem. Do not get offended though. I think it is hot you asked for help. Very sexy! (I am a girl BTW) "Those who do not understand the importance of mathematics are not human, but merely sub-human in that they have only learned to bathe and not make messes in the house." -- R. Heinlein 1969. (from memory, but the gist is the same.) Here is one of mine. "Opinions are for politicians, give me your facts and to how many decimal places." Good luck with your figures and remember women LOVE a man with a big brain most of all! Quote Link to comment Share on other sites More sharing options...
The Kid Posted August 18, 2008 Author Share Posted August 18, 2008 thanks alot, one experience i had was me filling up to a slight notch above 3/4.... (hey I was broke) and reset the trip and got about 137 miles.... i do not think that is good at ALL especially for how much gas this car holds Ianslexus, my method was basically the same thing as yours except filling ALL the way up I do use premium all the time, i could imagine how much faster it would burn if i had used regular.... does anyone even use regular? I only knew one guy with an sc 400 that used regular. Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted August 18, 2008 Share Posted August 18, 2008 With my regular commute I get about 100 miles per 1/4 tank. It all just depends on how heavy my foot is :D Hey IS400 do you know any other females driving LS400's?? Most women I've seen with Lexus' are into the IS300's cause they are "sssssooooooooooooooooooooooo cute!" Girls in big LS' are cutie pies hahaha Quote Link to comment Share on other sites More sharing options...
IS400 Posted August 18, 2008 Share Posted August 18, 2008 With my regular commute I get about 100 miles per 1/4 tank.It all just depends on how heavy my foot is :D Hey IS400 do you know any other females driving LS400's?? Most women I've seen with Lexus' are into the IS300's cause they are "sssssooooooooooooooooooooooo cute!" Girls in big LS' are cutie pies hahaha I think the IS300's are too ricer. I want a man to be interested in me; not teenage boys! I love the wheels though as you can see. The ISF is OK but needs to be more BMW M3ish to get me to spend that kind of money on a small car. It needs to look like a future classic like the 400s did when they came out. If I had space for more than two pictures in my gallery I'd show you more of me, the Infamous IS400, but the program says I have exceeded my quota with just a couple of uploads. Have a great night guys! P.S. I run regular all time. The computer compensates fine. Not all octane is exact from station to station IMO so that variation must be written into the EPROM architechure as a protection because I have never had a knock or hesitation. Full premium, does give me a little more of a performance kick in the pants though... ...make sure to check your battery and alternator. These cars lose performance when the voltage is not up too snuff I have heard. They run a high demand ignition system. Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted August 19, 2008 Share Posted August 19, 2008 I also wouldn't mind having a beautiful set of big wheels, but I don't want to decrease my MPG..... maybe I'll have to stick with a nice set of smaller wheels..... 18" 430 chrome 5 spokes are nice.... Quote Link to comment Share on other sites More sharing options...
IansLexus Posted August 19, 2008 Share Posted August 19, 2008 I also wouldn't mind having a beautiful set of big wheels, but I don't want to decrease my MPG..... maybe I'll have to stick with a nice set of smaller wheels..... 18" 430 chrome 5 spokes are nice.... jcrome I have 20" rims/tires on my 92 LS.. but much do you think that affects my fuel economy? I am currently getting about 15.5-16 all city, and 19-19.8 all highways. Do you think I would be getting a lot better if I took them off? Or would it only be 1 or 1.5 mpg? I understand you probably arent an authority on this, BUT, I know you had a 1gen with 20s, and how a 2gen with much closer to stock size -- so maybe you know! Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted August 19, 2008 Share Posted August 19, 2008 Yes there will be a significant drop in mileage when you put on big heavy 20"s My old 1st gen got even worse than what you are now. I know I'm no expert as well, but if you get some nice lighter 17"s or 18"s I'd say you could get maybe around 2mpg more...? Weight has a decent effect on mileage. The most I've got on a 95% highway, 5% city mix was 29.3 mpg. I think it has a lot to do with how the vehicle is maintained, and what type of fluids you use. (ie: fuel, oils, filters) and how often it is maintained. Quote Link to comment Share on other sites More sharing options...
The Kid Posted August 19, 2008 Author Share Posted August 19, 2008 well darn it jcrome give us alll your secrets and tips u have the highest mpg ive heard Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted August 20, 2008 Share Posted August 20, 2008 Synthetic fluids, Denso Iridium plugs, proper maintinence.... I clean out my air filter maybe once a week.... hahaha lots of bugs up here. light foot and cruise control 60mph! lol. But remember it's only possible if you can resist the urge to dump your foot into the pedal! :D :D :D Quote Link to comment Share on other sites More sharing options...
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