Author Topic: What's happening to fuel efficiency?! (Read 3222 times)

bf7890 · « **on:** February 19, 2005, 10:26:30 pm »

I was wondering if someone might give me tips on improving the fuel efficiency of my car. For the last 6 months, my car guzzles gas like crazy. This problem appears to have occurred suddenly. For 5 years, I've done 60km/day in heavy stop-and-go traffic. Then for another 2 years, it was 60km/day on the highway. (What can I say ... I find jobs that are nowhere near my home!) I've always managed to get about 250km to the 1/2 tank level. I recently moved back home to become a full-time student and that is precisely when I noticed by 1/2 tank, I've done about 170-180km. I thought that maybe the gas guage was off but when I did the calculations after filling the tank with gas, it proved that my car is happily guzzling gas. Although I am doing more "city driving", I know that this is not the problem because I use to do painfully slow stop-and-go driving for 5 years without losing this much gas. I also use dedicated winter tires (pressure okay) but again, I can't imagine that would cause fuel efficiency to dip this low.

My car is now being service by a local mechanic for basic stuff like oil changes. Could this be the problem? (i.e. type of oil, etc.) The only technical problem I've had recently was a missing bolt near the alternator (car was making crazy, squealing noises). Other than this, I do maintenances meticulously at scheduled intervals.

I'll be visiting my old mechanic in Toronto (very reliable guy) next week for a full inspection but was wondering if someone can give me some tips on what should be checked. I would imagine this includes: air filter, fuel filter, and spark plugs.

Any tips from the experts is appreciated!

barrie1 · « **Reply #1 on:** February 19, 2005, 11:42:59 pm »

Yes it would include most of these parts altho not necessarly the Fuel Filter if it is inline type. They probably will change the plugs and possibly the spark plug wires and cap and rotor on your car. Definitely your air filters and PCV valve as well. What is the Make and Model and engine size with milage of your car please? The more we know the better we can help you.

bf7890 · « **Reply #2 on:** February 20, 2005, 12:22:50 am »

Thanks Barrie1.

185,000km on a 1998 Acura EL / 45L tank ... which barely can make it to 400km these days / 4 cylinder VTEC engine / regular maintenance done / timing belt changed at around 165,000km

I am quite a freak about regular maintenance so it makes me wonder if there's something more than the regular stuff like spark plugs, air filters, etc.

One thing I forgot to mention is that up until about a year ago, I used to fill up with "Super" gas from Esso. (I know, I know, it doesn't enhance performance ... I figured I would be treating my car with "cleaner" gas ... now I know better.) When I made the change to Regular gas, I didn't notice a change in gas consumption.

articsteve · « **Reply #3 on:** February 20, 2005, 01:58:52 am »

One of your oxygen sensors might not be the best and the motor is running richer than normal. Examine all park plugs tips.

As for gas, I would stay away from Esso, Shell, PetroCanada, all 3 sold thru Crappy Tire as well, because these are all high sulpur gasolines and things like oxygen sensors don't do well on them.

Sunoco or Pioneer (Sunoco) is low sulphur gas or at least lower.

onearmed · « **Reply #4 on:** February 20, 2005, 03:30:14 am »

Articsteve: What you said about low sulphur gas was true up until about a year ago. I believe Esso currently has the lowest sulphur gas in Canada now. They've invested a lot in upgrading their refineries. There should be some info on the internet if you do some research. Just passing some info along!

onearmed · « **Reply #5 on:** February 20, 2005, 03:38:28 am »

http://foecanada.org/index.php?option=content&task=view&id=15&Itemid=32&limit=1& limitstart=8

Sorry a little off topic. Here is a chart of the sulphur levels in current gas.

inco · « **Reply #6 on:** February 20, 2005, 07:31:14 am »

Good find Onearmed. Wow - such a wide variation.

Not all refineries are created equal.

tpl · « **Reply #7 on:** February 20, 2005, 08:37:15 am »

However. FOE is not the most unbiased source around. I have been watching the Ont Gov web site for the last two years and it shows a somewhat different story, ( the final update to the Ont site is due in a few weeks) that the refineries that ship gas to Ont have been reducing towards the 30ppm limit in a reasonable fashion... you cant do this sort of refit in a week or a month.

Imp oil and Sunoco were ahead of the game, easier for Sunoco 'cos of the ethanol blend. Petrocanada trailed behind.

I believe that the Federal DIESEL sulphur limits are either Jan or dec 2006.... the transport industry screamed at that as it will make the fuel more expensive

safristi · « **Reply #8 on:** February 20, 2005, 09:50:00 am »

How come Shell from Scoford!! on the Prairies has been selling and winning the low Sulphur race since forever?

they were at 15 (Level ppm??) way back...then up to 50 now at 10...do they use a local excellent,pure basestock?

airbalancer · « **Reply #9 on:** February 20, 2005, 09:54:31 am »

Is this just a winter problem, less mpg, in winter.
Are driving on more hills now.
usually with super gas, mpg goes up.
More BTU's in super gas,

bf7890 · « **Reply #10 on:** February 20, 2005, 11:27:16 am »

About staying away from Esso, Petro-Canada, and Shell - YIKES! There are no Pioneers or Sunocos around in Montreal. I'm not sure where the local brands like Crevier are sourced. When I was living in Toronto, I used to fill up at Esso in Mississauga. Could the gas be sourced differently in Mtl?

safristi · « **Reply #11 on:** February 20, 2005, 01:34:16 pm »

Where are the GAS ENGINEERS whn ya need one

PHHHAAAAARRRRPPPTTTTTTTT!!!!!!!ah that explains everything... I ..Phrrpt..think..Pharppt...that..Pheiirpp..someone..Phiirpp..should Blaarp...see...Phhooppt...about..pheerpppt..excuse me it's getiin' dangerous in here......

articsteve · « **Reply #12 on:** February 20, 2005, 02:18:34 pm »

Onearmed; thank you that. I went to Esso's website and they state about 30 whatever across the board in all of 2004 so I am not going to avoid their gas. However, I am still pissed at Exxon due to them going to "court" and weaseling out of their Valdez oil spill re-payements.

Airbalancer; there is less energy per volume in high octane gas than low octane (regular).

barrie1 · « **Reply #13 on:** February 20, 2005, 08:57:04 pm »

That might be true in the Winter Time but tell that to my Truck come Summer Time. It will hardly pull its own weight on Reg. Ping like crazy as well. Its a higher Compression engine.

articsteve · « **Reply #14 on:** February 21, 2005, 02:34:24 am »

Regular gasoline burns faster and hotter than premium, so in theory it contains more energy. So buying premium gas thinking that your car will go farther because it contains more energy is wrong.

10% ethanol blends have generally 3% less BTUs per gallon than regular gas, but result in a higher combustion effiency so offer equal or slightly better mileage.

High octane gasoline is used to control detonation in high compression motors by doing a few things all heat/temperature related. That is their only benefit, not increased energy over regular gas.

(Message edited by articsteve on February 21, 2005)

maritime_storm · « **Reply #15 on:** February 21, 2005, 04:26:44 am »

Back to the topic at hand, 185,000kms as someone pointed screams time for new O2 sensors and changing of your air{if needed} & fuel filters, PCV valve, and plugs. The O2 sensors will most likely make the biggest difference. Also check your temperature sending unit{the one for the PCM}, if it s failing it will also cause your car to run rich, idle funny and be harder to start, among other things.

ardentib · « **Reply #16 on:** February 25, 2005, 10:07:26 pm »

Hi,
I just bought a 2003 ZX5 auto/winterpackage with only 10 Kms.
Seems to eat gas. How many kms should one get from a full tank ?
Dennis

bf7890 · « **Reply #17 on:** February 26, 2005, 08:30:59 am »

Ardentib - Did you mean a 2005 instead of a 2003 model? What is the tank and engine size? Do you drive manual or automatic?
From what little I know about the Ford Focus, it is a peppy car with a bigger engine - much more horsepower than other cars in its class (Civic, EL, basic Corolla), so it will definitely eat more gas.

ardentib · « **Reply #18 on:** February 26, 2005, 03:32:01 pm »

2003 ZX5 Focus Automatic with 10,000 Kms and eating gas. Imean like 300 kms /tank with just me driving very moderately.
Not sure how to approach Ford. Have lots of Warranty.
Dennis

cosmo · « **Reply #19 on:** February 26, 2005, 04:15:30 pm »

I would like to add the obvious question that all of you have seemed to miss...but are you ever quick to change sensor's...Although I would suspect some of the sensors such as the O2 sensor(s, Cat clogged, ECT sensor (s)...Have you considered that maybe the engine is getting tired? Have you perfromed a compression test? You might have a low cyl(s) either rings, cyl worn, or the dredded burnt valves.

Just thought you should consider it

Cosmo