dhyndi Posted September 12, 2012 Share Posted September 12, 2012 Hello All! I've never been under any illusion that a 350z is an economical car to drive where fuel is concerned, however I think mine is under performing a bit and was wondering if anyone has any suggestions. I'm currently getting 21.6 mpg, and thats from alot of freewheeling and driving about like someones granny. A friend of mine is looking to buy a Z and the ones he has been test driving are getting between 26 & 28mpg without a problem, mines a 2004 and i've owned it 2 years and never seen it close to that. The car is well serviced and has had oil and plugs replaced recently, tyre pressures regularly topped up and run on super unleaded. Could carrying out the "fuel gauge fix" improve the MPG reading....or is there anything else I should look for? Thanks in advance Dave Quote Link to comment Share on other sites More sharing options...
Flex Posted September 12, 2012 Share Posted September 12, 2012 Have you calc'd the MPG manually, rather than using the car's? Quote Link to comment Share on other sites More sharing options...
ioneabee Posted September 12, 2012 Share Posted September 12, 2012 Apart from the "danger" issues - no comment freewheeling will not help - consider - engine out of gear needs fuel to keep it running, now consider - leave in gear and coast down hill etc, no fuel needed to keep the engine ticking over = free mileage Quote Link to comment Share on other sites More sharing options...
dhyndi Posted September 12, 2012 Author Share Posted September 12, 2012 well i'm getting 70 miles to £20 according to the fuel gauge?? Quote Link to comment Share on other sites More sharing options...
Leeroy Posted September 12, 2012 Share Posted September 12, 2012 21 mpg isnt that far off what it should be and if you're labouring the engine too much it you can end up using more juice than you would at optimal revs. You should achieve 24 or 25 mpg if aren't tear-arsing around everywhere though. If you're that worried you should take it into a trusted Zed specialist for a check-up - where are you based? I'm sure you don't need telling that the 350Z will never be 'economical' Quote Link to comment Share on other sites More sharing options...
dhyndi Posted September 12, 2012 Author Share Posted September 12, 2012 Yeah, i take it fairly easy, only rake it now and again. I know it will never be economical, just accepted that it was that bad, but these ones my mates been driving seem a fair bit higher. I'm based in Belfast, have a Zed specialist who has gone independant that looks after the car, going to throw it up to him soon, just wondering if anyone had any similar experiences or thing to look out for. Could the rotting joins on the exhaust contribute?? Going to get them cut out and replace with stainless steel soon too Quote Link to comment Share on other sites More sharing options...
GT4 Zed Posted September 12, 2012 Share Posted September 12, 2012 3 piece of advise: 1- MAF I had a dip in my fuel consumption a few months back and traced it to my MAF. i founs a ting piece of leaf that had work its way and was blocking the hot wire i carefully picked it up with small tweezers and sprayed the wires with electrical cleaner spray from halfords and let it try and refitted. My MPGs got back to 26-32 as before. beware of the effect of some mods to the car if any. 2- Throttle controller The next investment i would suggest is a D1 controller. It will pay itself in no time Mind you my car is NA tuned with all mods concievable but i return 28-32 MPG on motorway at 85-90mph and 22-26 in busy town track. At SP7 on track i have 9-15mpg 3- Driving style. hard accelerations riding on the wrong gears, staying to long on a gear etc all impact MPG dramatically so look into what you can change. Also loose some weigt off the car if you are really trying, spare wheels etc, carry 1/4 or 1/2 tank of fuel at a time. If all fails get you car ecu checked and exhaust for no leaks etc But at the end of the day its a 3.5l 1.5 ton bit-h so what do you expect Quote Link to comment Share on other sites More sharing options...
dhyndi Posted September 12, 2012 Author Share Posted September 12, 2012 thanks! i dont expect it to be doing 40mpg or anything, just think mine is going a bit harsh! will be getting the exhaust leaks checked soon and will have a look at the MAF this weekend hopefully. 28 - 32mpg is the stuff of dreams for me....if i could get it to 26/28 i'd be delighted! Main reason for this post was just to see if anyone had done anything or had anything fail that changes their mpg for better or worse! Quote Link to comment Share on other sites More sharing options...
nickzzz Posted September 12, 2012 Share Posted September 12, 2012 I generally get 25-27mpg general driving. On a recent 600 mile trip generally just sticking to speed limit and mostly motorway I averaged 34mpg! Was impressed. This is all on the trip computer and not properly calculated mind! Maf is a posssible issue&coasting in neutral won't help. Quote Link to comment Share on other sites More sharing options...
dhyndi Posted September 12, 2012 Author Share Posted September 12, 2012 I generally get 25-27mpg general driving. On a recent 600 mile trip generally just sticking to speed limit and mostly motorway I averaged 34mpg! Was impressed. This is all on the trip computer and not properly calculated mind! Maf is a posssible issue&coasting in neutral won't help. yeah, 25-27 is what i'm trying to achieve! only tried the coasting over the last week to see if it made a difference - it didnt! Quote Link to comment Share on other sites More sharing options...
docwra Posted September 12, 2012 Share Posted September 12, 2012 Like Bennett says, check your AFM is working, it might be worth making sure the lambada sensor is in full effect as well. The best Ive ever seen from mine is about 22 mpg but I drive hard .......... try not exceeding 3K rpm for a bit and see what happens Quote Link to comment Share on other sites More sharing options...
dhyndi Posted September 12, 2012 Author Share Posted September 12, 2012 yeah, been keeping it below 3k revs the past week to see if it improved - it didnt! think i'm going to get the exhaust looked at, its my main area of suspision. all the factory joinging points are quite badly decayed Quote Link to comment Share on other sites More sharing options...
KyleR Posted September 12, 2012 Share Posted September 12, 2012 I think what you're getting is normal, I get about 20-21 usually as i dont tend to do many long journeys, but motorway its low 30's and high 20's for open A roads. Quote Link to comment Share on other sites More sharing options...
Keyser Posted September 12, 2012 Share Posted September 12, 2012 Stop it the lot of you!!!!!!!!!!!! I average 18MPG calculated by fuel in and miles covered I don't have an on board trip anymore, but from here to Keevil round track and home I got ............ 8MPG Good job it's not my daily Quote Link to comment Share on other sites More sharing options...
Drayvn Posted September 12, 2012 Share Posted September 12, 2012 I get 20.5 mpg but that's because our speed limit around here is 35. I swear it lies to me... Quote Link to comment Share on other sites More sharing options...
Paddy78 Posted September 12, 2012 Share Posted September 12, 2012 I never see better than 20.7MPG... this is a mixture of commuting a short distance and weekend drives. I've never been worried about a problem, but might be worth checking the MAF etc. Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted September 12, 2012 Share Posted September 12, 2012 Apart from the "danger" issues - no comment freewheeling will not help - consider - engine out of gear needs fuel to keep it running, now consider - leave in gear and coast down hill etc, no fuel needed to keep the engine ticking over = free mileage Hmmmm.. but on the other hand, if you leave it in gear, the engine braking will cause the car to slow down and stop after a bit. Whereas if you leave it out of gear, no engine braking and the car will happily coast for miles (well.. or at least until the gradient changes) Does the engine really use no fuel if you take your foot off the throttle and are on the over run? Or is it still sucking fuel through as the engine is doing say 3000rpm (for example) compared to 800rpm (for example) if its idling and your in neutral. Quote Link to comment Share on other sites More sharing options...
sparky370z Posted September 12, 2012 Share Posted September 12, 2012 i like to be in control at all times. very, very little coasting. never on purpose. Quote Link to comment Share on other sites More sharing options...
KC350Z Posted September 12, 2012 Share Posted September 12, 2012 well i'm getting 70 miles to £20 according to the fuel gauge?? Same as mine on normal driving only goes down from there tho Quote Link to comment Share on other sites More sharing options...
BulletMagnet Posted September 12, 2012 Share Posted September 12, 2012 My solution to this was to unlearn myself from knowing what MPG means. But also about to receive a can of BG44K in the post and see if it helps cleaning out the fuel system and removing any carbon buildup on the engine internals. Heard good reviews and my bro did the treatment on his SC'd Celica with good results. Quote Link to comment Share on other sites More sharing options...
docwra Posted September 12, 2012 Share Posted September 12, 2012 Apart from the "danger" issues - no comment freewheeling will not help - consider - engine out of gear needs fuel to keep it running, now consider - leave in gear and coast down hill etc, no fuel needed to keep the engine ticking over = free mileage Hmmmm.. but on the other hand, if you leave it in gear, the engine braking will cause the car to slow down and stop after a bit. Whereas if you leave it out of gear, no engine braking and the car will happily coast for miles (well.. or at least until the gradient changes) Does the engine really use no fuel if you take your foot off the throttle and are on the over run? Or is it still sucking fuel through as the engine is doing say 3000rpm (for example) compared to 800rpm (for example) if its idling and your in neutral. Dude, its a fact, an engine on overrun doesnt use any fuel as the engine braking keeps it turning over, if its on tickover it needs fuel to keep running. Even at 8500rpm as soon as you are off the throttle the injectors stop putting fuel into the cylinder The resistance is neither here nor there, you arent using anything at all on overrun Quote Link to comment Share on other sites More sharing options...
jollyranchers Posted September 12, 2012 Share Posted September 12, 2012 Ive never seen more than 21 from mostly town driving , welcome to the zed world Quote Link to comment Share on other sites More sharing options...
Big Rob Posted September 12, 2012 Share Posted September 12, 2012 I have never acheived an average as high as 21mpg, your car seems fairly economical! Quote Link to comment Share on other sites More sharing options...
C.J Posted September 15, 2012 Share Posted September 15, 2012 Mines used as a daily, and currently I average 25.7mpg. Although this last month, I've been driving very steady, with the aim to see just how good it can be on fuel. Quote Link to comment Share on other sites More sharing options...
glrnet Posted September 15, 2012 Share Posted September 15, 2012 My solution to this was to unlearn myself from knowing what MPG means. But also about to receive a can of BG44K in the post and see if it helps cleaning out the fuel system and removing any carbon buildup on the engine internals. Heard good reviews and my bro did the treatment on his SC'd Celica with good results. I'd be interested to know the results of that Quote Link to comment Share on other sites More sharing options...
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