question on getting better mpg
11-20-2010, 10:34 PM
#1
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question on getting better mpg
My 98 Max has been getting worse and worse with gas efficentcy. I need some help on what I can to make it better. I know that driving behavior is the biggest thing but I'm not always gunning it or slamming the breaks.
I'll be taking her to the shop soon to get the engine service light checked out and taken care of and I was curious as to what else I could have replaced or cleaned while she's in the shop.
I've heard yes and no for this question but will a cold air intake slightly improve fuel efficiency?
I'll be taking her to the shop soon to get the engine service light checked out and taken care of and I was curious as to what else I could have replaced or cleaned while she's in the shop.
I've heard yes and no for this question but will a cold air intake slightly improve fuel efficiency?
11-20-2010, 10:43 PM
#3
CAI could help a bit (but you probably wouldn't notice anything other than the sound which I like 
There is more surface area on a cone filter than the stock filter, so there should be less flow resistance, theoretically improving performance and efficiency, but the surface area difference isn't normally enough to change much. The stock intake is a bit restricting though. If you haven't changed spark plugs in 50,000 miles I would do that. I would also run injector cleaner and clean the throttle body.
If you have noticed a slight loss in power too I would check codes for a knock sensor. They malfunction pretty commonly and are cheap ($20 ebay) and easy to replace. When they go bad the engine can't sense knocking in the cylinders, so the ECU retards the timing as a precaution resulting in a slight power loss and less efficient burning of the fuel in the cylinders. Hope this helps.
oh and what he said
^
There is more surface area on a cone filter than the stock filter, so there should be less flow resistance, theoretically improving performance and efficiency, but the surface area difference isn't normally enough to change much. The stock intake is a bit restricting though. If you haven't changed spark plugs in 50,000 miles I would do that. I would also run injector cleaner and clean the throttle body. If you have noticed a slight loss in power too I would check codes for a knock sensor. They malfunction pretty commonly and are cheap ($20 ebay) and easy to replace. When they go bad the engine can't sense knocking in the cylinders, so the ECU retards the timing as a precaution resulting in a slight power loss and less efficient burning of the fuel in the cylinders. Hope this helps.
oh and what he said
^
11-20-2010, 10:49 PM
#4
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TBH I did search a bit and just found a buch of threads of people posting about how many mpgs they're getting or complaining how bad or good theirs. I never have any luck searching for things I need to know lol it can take forever for me to find what I'm looking for and usually it's after I've done whatever I need to do so it's of no use anymore...
Thanks for the info I'll prob have all that stuff taken care of when I get her to the shop for my start up problem and service engine light. (P.S. I love that sweet induction sound from a cai too)
Thanks for the info I'll prob have all that stuff taken care of when I get her to the shop for my start up problem and service engine light. (P.S. I love that sweet induction sound from a cai too
)
11-21-2010, 07:05 AM
#5
Well, first you need to figure out why your check engine light is on. You don't need to take it to the shop to do that. Here's the procedure http://vbxmaxima.8m.com/ecu.html
Once you diagnose what the check engine light is on for, we'll be able to help more. It could be something simple like a sensor. Report back here and you'll get more help.
And I doubt a CAI will help with MPG; you'll just want to hear it roar so you go WOT more.
Once you diagnose what the check engine light is on for, we'll be able to help more. It could be something simple like a sensor. Report back here and you'll get more help.
And I doubt a CAI will help with MPG; you'll just want to hear it roar so you go WOT more.
11-21-2010, 07:49 AM
#6
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Well, first you need to figure out why your check engine light is on. You don't need to take it to the shop to do that. Here's the procedure http://vbxmaxima.8m.com/ecu.html
Once you diagnose what the check engine light is on for, we'll be able to help more. It could be something simple like a sensor. Report back here and you'll get more help.
And I doubt a CAI will help with MPG; you'll just want to hear it roar so you go WOT more.
Once you diagnose what the check engine light is on for, we'll be able to help more. It could be something simple like a sensor. Report back here and you'll get more help.
And I doubt a CAI will help with MPG; you'll just want to hear it roar so you go WOT more.
11-21-2010, 10:03 AM
#7
That seems like a good idea but everytime I try to do a DIY I screw up everything and I'm no machanic so it'll be going to the shop even if it's something as simple as a sensor. I'd love to do the work myself and eventually it's something I'd love to be able to know what I'm doing but for now I can't risk screwing something up lol it's my only means of transportaion.
Good luck.
11-21-2010, 10:29 AM
#8
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I'm 18, it's my first car, just got a new job so maybe some day down the road when I'm more finacially able to tinker with my max I'll start doing my own repairs
11-21-2010, 11:35 AM
#9
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Join Date: Oct 2010
Location: Chicago, IL
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whenever mileage drops Id say start with a good tune up,,,,, with your CEL light on that could be all your problems right there.
These are known to use O2 sensors,,,, could be causing you to dump more fuel, which could foul the plugs,,,,see where im going with this
These are known to use O2 sensors,,,, could be causing you to dump more fuel, which could foul the plugs,,,,see where im going with this
11-21-2010, 05:10 PM
#10
My car never got a CEL but my MPG has been going in a downward spiral with MPG. Before I got 26 MPG now its down to 19-21 MPG. And I checked for ghost codes and didnt get a single one, not even for a knock sensor.
One of the things I did was inflate all the tires to almost MAX PSI and that only helped for a while then my MPG went back to the same.
Then I change the air filter cause I haven't change mine in two years and it had the fuzzy tree seeds all over so might as well. And it helped with power a bit but MPG stayed the same.
Then I ran Techron and I noticed a increase in acceleration but MPG went up like one or two
Then after a few months I ran Seafoam and a bunch of black smoke came out, my car had a previous history of running super rich from a bad MAF and I haven't done anything to clear out the mess so... that explains the black smoke. But so far it seems like Seafoam through the brake booster helped me the most. So far I've gone about 1/4 of the tank and got 110 miles. Which is a lot better than what I've got previously but I need to wait until I go through the whole tank to really know.
One of the things I did was inflate all the tires to almost MAX PSI and that only helped for a while then my MPG went back to the same.
Then I change the air filter cause I haven't change mine in two years and it had the fuzzy tree seeds all over so might as well. And it helped with power a bit but MPG stayed the same.
Then I ran Techron and I noticed a increase in acceleration but MPG went up like one or two
Then after a few months I ran Seafoam and a bunch of black smoke came out, my car had a previous history of running super rich from a bad MAF and I haven't done anything to clear out the mess so... that explains the black smoke. But so far it seems like Seafoam through the brake booster helped me the most. So far I've gone about 1/4 of the tank and got 110 miles. Which is a lot better than what I've got previously but I need to wait until I go through the whole tank to really know.
11-21-2010, 06:41 PM
#11
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Thanks for the info guys I really appreciate it. I'll just go have my car tuned up and if it helps great, if not oh well I'll just have to deal with it. I used to get a week and a half to 2 weeks driving to and from school about 4 miles away from my house Monday through Friday and I think ever since I put on my Megan Racing exhaust it made a difference.
02-11-2011, 10:14 AM
#12
I'm getting like 16mpg with mostly city driving. I'd say 70% city. I don't think this is normal.
Might I add I live in Quebec (CANADA) where I'd be driving in snowy conditions from time to time.
My tire pressure is set at 32psi.
I use 87 octane fuel. I tried the 91 octane but didn't notice a difference except in my pocket. To put you in perspective, we pay around 1.20$/L at the pump or 4.55 the gallon, which I believe is more expensive than in the states.
My CEL has been on forever. I had an issue with the O2 sensors at one point. Changed them. Then the CEL came back on. I believe for the same reason. I have to 2x check that this weekend.
To what degree do the O2 sensors affect consumption?
I read quite a bit on other threads as to what I can do but most people were complaining about their 20-21 mpg efficiencies. 16 is just getting ridiculous.
I'm also gonna be keeping the car for probably another 50 000 miles max. It currently has a little over 100 000 miles. So I don't really want to be spending on something that won't pay for itself...
Any help is appreciated.
Thanks guys.
Might I add I live in Quebec (CANADA) where I'd be driving in snowy conditions from time to time.
My tire pressure is set at 32psi.
I use 87 octane fuel. I tried the 91 octane but didn't notice a difference except in my pocket. To put you in perspective, we pay around 1.20$/L at the pump or 4.55 the gallon, which I believe is more expensive than in the states.
My CEL has been on forever. I had an issue with the O2 sensors at one point. Changed them. Then the CEL came back on. I believe for the same reason. I have to 2x check that this weekend.
To what degree do the O2 sensors affect consumption?
I read quite a bit on other threads as to what I can do but most people were complaining about their 20-21 mpg efficiencies. 16 is just getting ridiculous.
I'm also gonna be keeping the car for probably another 50 000 miles max. It currently has a little over 100 000 miles. So I don't really want to be spending on something that won't pay for itself...
Any help is appreciated.
Thanks guys.
Last edited by thebaker; 02-11-2011 at 10:17 AM.
02-11-2011, 10:48 AM
#13
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Join Date: Jun 2005
Location: Montreal
Posts: 294
thebaker:
I'm in Montreal and I own 2 maximas. One is 210,000kms and the other is 250,000 kms. I often got the o2 sensors but after replacing then, I never really saw any mileage increase. Both of my cars average about 520 kms (in trafficy Montreal). I also use 87 but I use FP60 fuel additive with every other tank.
Check you air filter.
I would also clean out the EGR tube...you know that dreaded task of removing the MAF, and clean out the throttle and the EGR...I did this with both car and man, both cars got increase performance, almost like new, and yes it was not only dirty but almost clogged (got no codes when I did it)...this is a 3-5 hour job. I can't say the mileage increaed because both car were running well - I just wanted to clean it out since I want these car to last me a lifetime.
I did it myself, and the local nissan refused to do it. I also replaced EGR-Valve, BPT EGR, solenoid, EGRTube, PCV valve and cleaned IACV, and MAF.
I have a great canadian site to get those genuine parts cheap here:
http://www.autopartsonlinecanada.com/
There is also a cheap junk yard near my place that has (or had) a few maximas, might be good if you need a new MAF.
If you ever want to compare engines, and your in montreal, ring me up.
BTW: Are you really a baker?
I'm in Montreal and I own 2 maximas. One is 210,000kms and the other is 250,000 kms. I often got the o2 sensors but after replacing then, I never really saw any mileage increase. Both of my cars average about 520 kms (in trafficy Montreal). I also use 87 but I use FP60 fuel additive with every other tank.
Check you air filter.
I would also clean out the EGR tube...you know that dreaded task of removing the MAF, and clean out the throttle and the EGR...I did this with both car and man, both cars got increase performance, almost like new, and yes it was not only dirty but almost clogged (got no codes when I did it)...this is a 3-5 hour job. I can't say the mileage increaed because both car were running well - I just wanted to clean it out since I want these car to last me a lifetime.
I did it myself, and the local nissan refused to do it. I also replaced EGR-Valve, BPT EGR, solenoid, EGRTube, PCV valve and cleaned IACV, and MAF.
I have a great canadian site to get those genuine parts cheap here:
http://www.autopartsonlinecanada.com/
There is also a cheap junk yard near my place that has (or had) a few maximas, might be good if you need a new MAF.
If you ever want to compare engines, and your in montreal, ring me up.
BTW: Are you really a baker?
02-11-2011, 10:54 AM
#14
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Join Date: Jun 2005
Location: Montreal
Posts: 294
The info on this forum is soo huge now that if you do any search you get 100's of pages to filter thru.
Before I post I do some searches, but after a few hours of not getting what I need I give up...plus they are old threads and a new post might invite other loggers to post recent activities.
Cheers bud!
02-11-2011, 11:06 AM
#15
Common max-ride 41, lighten up..this forum is slowly dwindling and we need to keep this small little family together here.
The info on this forum is soo huge now that if you do any search you get 100's of pages to filter thru.
Before I post I do some searches, but after a few hours of not getting what I need I give up...plus they are old threads and a new post might invite other loggers to post recent activities.
Cheers bud!
The info on this forum is soo huge now that if you do any search you get 100's of pages to filter thru.
Before I post I do some searches, but after a few hours of not getting what I need I give up...plus they are old threads and a new post might invite other loggers to post recent activities.
Cheers bud!
There are like 4 epic mpg threads that have a ton of quick fixes for under $20 for your MPG woes.
02-11-2011, 11:18 AM
#16
I don't understand why this is an issue. Fix you car then it will perform better. If you can't fix it yourself (doubtful, with patience) then pay someone to fix it soon...you are wasting money on gas anyway.
My car is as tuned up as it gets, all sensors, filters, ignition components, etc. are new(er). I get low to mid 20's in mixed driving. Fix your car and all is well. /thread
My car is as tuned up as it gets, all sensors, filters, ignition components, etc. are new(er). I get low to mid 20's in mixed driving. Fix your car and all is well. /thread
02-11-2011, 04:15 PM
#18
02-11-2011, 05:05 PM
#19
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Posts: 116
It takes a newb to post a repost of a repost of a repost and because of max ride 41 I have started doing research on the .org and use search engines as well. Honestly, I found that if you just take the time to look through the threads thoroughly, you will eventually come across an answer. It probably saved me headaches of hearing comments telling me to just SEARCH.
I just came to the conclusion that every car runs different, everybody drives differently, and from doing research after being told to search for this topic, the best comments I saw was "You're driving a Maxima, NOT A HONDA if you want better mpg go buy a civic." and "Maintenance, maintenance maintenance."
If hours of searching is getting tiresome than search on google and if you still don't get the answer you're looking for then call or drive to the nearest auto part store or mechanic. That's what I've done and it's a lot easier than posting a thread and waiting for a response. I still consider myself a newb here but after a while of lurking you know what's worth posting.
I just came to the conclusion that every car runs different, everybody drives differently, and from doing research after being told to search for this topic, the best comments I saw was "You're driving a Maxima, NOT A HONDA if you want better mpg go buy a civic." and "Maintenance, maintenance maintenance."
If hours of searching is getting tiresome than search on google and if you still don't get the answer you're looking for then call or drive to the nearest auto part store or mechanic. That's what I've done and it's a lot easier than posting a thread and waiting for a response. I still consider myself a newb here but after a while of lurking you know what's worth posting.
02-11-2011, 07:03 PM
#20
It takes a newb to post a repost of a repost of a repost and because of max ride 41 I have started doing research on the .org and use search engines as well. Honestly, I found that if you just take the time to look through the threads thoroughly, you will eventually come across an answer. It probably saved me headaches of hearing comments telling me to just SEARCH.
I just came to the conclusion that every car runs different, everybody drives differently, and from doing research after being told to search for this topic, the best comments I saw was "You're driving a Maxima, NOT A HONDA if you want better mpg go buy a civic." and "Maintenance, maintenance maintenance."
If hours of searching is getting tiresome than search on google and if you still don't get the answer you're looking for then call or drive to the nearest auto part store or mechanic. That's what I've done and it's a lot easier than posting a thread and waiting for a response. I still consider myself a newb here but after a while of lurking you know what's worth posting.
I just came to the conclusion that every car runs different, everybody drives differently, and from doing research after being told to search for this topic, the best comments I saw was "You're driving a Maxima, NOT A HONDA if you want better mpg go buy a civic." and "Maintenance, maintenance maintenance."
If hours of searching is getting tiresome than search on google and if you still don't get the answer you're looking for then call or drive to the nearest auto part store or mechanic. That's what I've done and it's a lot easier than posting a thread and waiting for a response. I still consider myself a newb here but after a while of lurking you know what's worth posting.
02-11-2011, 09:12 PM
#21
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The guy who posted that comment today obviously figured out how to use the search if he found my post from November. He's almost got the hang of it now he just needs to click more than one thread to find the answers he's looking for.
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