Poor fuel milleage in '99 Altima

borrowed my brothers 93 altima for a couple weeks now, I noticed that the tank is not full at the first click at the gas tank. The highest it would get on the gas gauge was 3/4.

The other day I decided to fill it up myself. The gas nozzle clicked off at

22 liters (6 gall). I coaxed another 15 liters (4gall) into it! Afterwards, the gas gauge was at full.

Maybe your problem is similar? t

snipped-for-privacy@gmail.com wrote:

1st make sure that the gauge is reading correctly. Refuel the tank and compare the volume put in it with the specs for your car. If there is only 1/4 left, then you should be able to put 3/4 x fuel tank capacity.

Once you have confirmed that the gauge is ok, we will think of possible causes for the exagerated fuel usage.

Good luck

snipped-for-privacy@gmail.com wrote:

" snipped-for-privacy@gmail.com" wrote in news: snipped-for-privacy@g10g2000cwb.googlegroups.com:

A leak??

Yes, I will do that shortly. Just waiting for the tank to empty. It is wierd...it seems the last eighth is lasting almost 200 kms..so far we have gotten 350kms out of a full tank. The light hasn't come on yet, but I have been expecting this to come on for almost a week. It's as though the tank is severly lop-sided or something.

Ok, so update. My wife filled up the tank today...52 litres. She filled it up when the needle was past the E...but the light hadn't come on yet. The trip odometer said 427km. We had a full tank before too...so that works out to 8.21l/km. Not that good at all.

The whole car works great...any ideas anyone?

Actually it comes out to be 0.122 l/km or 8.21km/l or 19.45 miles/gal which is not desperately bad in my opinion, even should be improved. I would expect around 22 miles/gallon city driving.

Is it auto or manual transmission? Is it mostly city or highway driving? A/C on mostly? Are the tires on the vehicle of the right size (is the odometer reading distance correctly).

1. Tire inflation pressure and tire type have influence in gas mileage. What brand and model tires are they? Adjust inflation pressure when tires are cold.
2. Any chances of the brakes dragging the vehicle? Does it roll easily?
3. Wheel alignment.
4. Roof rack or any other gadgets that could affect wind resistance?
5. If auto tranny, is there a chance of slippage?
6. Air filter.
7. Spark Plugs and wires.
8. Is this car equipped with a timing belt or chain. If belt, has it been replaced?
9. Thermostat stuck in the open position.
10. Insufficient engine compression.
11. Improper ignition timing.
12. Oils change.
13. Too much junk in the trunk.
14. Codes on the ODB-II even if the CEL is not on

I hope this list helps.

Good luck

snipped-for-privacy@gmail.com wrote:

Sounds about the same as the mileage on the 93 altima I am planning to buy.

Altima's are pretty heavy compared to other similar sized cars. Also, engine displacement is higher than its competitors. Nissans are not know for their fantastic mileage.... if that is what you were goin for, you shoulda gotten a honda or toyota.... :)

BUT take some of the pointers that 'AS' suggested, as these points will also often help point you to other maintenance issues that should have been done anyways. And who knows, maybe you can squeeze another couple MPGs outta the car....

Try a bottle or 2 of Lucas Upper Cylinder Lubricant in the gas tank, or Chevron Techron (I've heard good things though never tried, can't find it in Canada....) If there is a compression issue due to carbon in combustion chamber or dirty valve train, that stuff will clear it right up. Increased compression on the 93 altima from 85 to 160 PSI, 80% leak down on intake valves to 35%.... so obviously it could still be improved....

t

snipped-for-privacy@gmail.com wrote:

Hey there. Thanks for the tips.

I just checked the tire pressure...they were all down at least 6 psi. I topped them all up.

The front tires have uneven wear on the outside edge. Very badly on the front right tire. I am getting the front end aligned this week.

Brakes are good...tranny is fine.

I have no exterior accessories (roof rack..)

I will check air filter/plugs/wires tonight. Maybe put a K&N in there.

I dont know about the timing belt or chain...but the alternator belt chirps once when I start it cold...will get that tightned at the time of alignment.

Not sure about the thermostat...but it heats up fine and really fast (Less than 2 mins of driving with a 30 sec warm up) in -0 celcius weather consistantly.

The timing/compression, i am unsure of. Things to check when I send it in.

Oil has been changed less than 500kms ago.

The car is empy aside from an empy gerry can and a blanket.

Regarding additives, not sure about nissan, but in my honda manual it says additives are a waste of money, but it does not say that they are not recommended. I guess just take a look at the additive. Chlorine and Teflon are common ingredients in some additived. These are not found in fuel or oil, so why would you put that in your engine? Higher quality additives are just re-refined oils with different properties, perhaps questionable in their efficacy. Lots of Injector cleaners are alcohol or petroleum distillates, so they should be fine. Only time you gotta worry is if it'll eat fuel lines and fittings....

Sometimes it just takes a tank of high octane and a lead foot to really clean out the combustion chambers....

I use the odd bottle of injector cleaner, seems to have done no damage so far. ... t

snipped-for-privacy@gmail.com wrote:

I was doing an emergency rebuild of a pickup so it'd pass inspection while camping in another state. I was kind of grimey when I'd buy parts. The parts store owner's son said Hey, try this Restore. It has Teflon that melts and fills any scratches in the cylinder walls improving compression. I used it, and again. The truck started smoking. The stuff may fill cracks but it also builds up on the valve stems. So, after using the stuff if you run the engine to a rev it usually never reaches the buildup tears into the valve seals. Smoke. I sometimes wonder about the carbon cleaners and their effect on O2 sensors. The chemical has to be pretty strong so what's the odds of it killing the chemical sensor and what's it do to the converter catalyst?