Fuel economy question for the Masters...

[AZhitman]

I know that I shouldn't expect Quella to be anything other than the greedy, fat-bottomed, premium-unleaded lush that she is.

However, she's consistently running around 14mpg with combined city and freeway driving without the A/C on. She has a spotless plenum and EGR, sparkling TB, new air filter, Mobil 1 throughout, new plugs, 38 psi per tire, no evident problematic readings per Consult... Can I reasonably expect a little more MPG than I'm getting? Perhaps it is as Brian said and she still thinks it's 120 degrees outside?

I'll be taking her in to the dealer again today (they scratched her by accident last time I was there).

What tests should I ask them to run, specifically?

[DAEDALUS]

Have you done the O2 sensors? If you average just 1mpg better over the next 60k, they'll pay for themselves. Take her in all warmed up like normal and haev them see if the timing's being retarded. I assume they can also find indicated temps from all sensors and compare them to actual.

[landtodd]

I know that I shouldn't expect Quella to be anything other than the greedy, fat-bottomed, premium-unleaded lush that she is.

LOL! Thanks. I needed that. Good call about the temp -- important to know what the ECU thinks it *ought* to be doing. Thermostat and two temp sensors possibly at fault.

[AZhitman]

She has a new thermostat and housing. Which temp sensors? The MAF? Or the water temp sensors?

O2 sensors are the originals - Dealer says they're fine, any way they can be tested?

GOTTA be able to do better than 14mpg, right?

[Q45tech]

There are 2 temperature sensors [a single wire inaccurate one for inside gauge] and a 2 wire accurate [when new] one telling ecu what the head output coolant temperature is!http://www.babcox.com/editorial/cm/cm12 ... chtemp.htm

What most don't see are the milestones during the warmup phase 122F, 138F, 160F,[176F.........194.99F], 195F,200F, 205F, 210F, 215F [over 220F.................]

Unless the ecu temp reads 176F or higher a multiplier is added to the fuel injection [[at 160F it is only about 3% but that means a bad thermostat can increase fuel consumption by 3-5% [or worse]] alone.

The point is you MUST observe the injector open time at idle and steady cruise to determine if you are using more fuel than you should [2.0 at idle and 2.2 at 60 mph cruise]........even 0.2 more means 10% more fuel than normal thus 10% less mileage.

If O2 sensors have 100k on them they maybe in spec [functioning?] but not optimum for squeezing every MPG out.........you must observe them on a scope and count the number of switches per minute and make sure the lean time is equal to the rich time [balanced]......called cross counts per minute.

Many things [tests] on a Consult say OK when it just means the item is functioning and has not totally failed.

If you have ever had a MAF failure or intermittent MAF contacts you always need an emission test to check the health of the CATS..........if HC is high the cats may have partially melted adding exhaust back pressure [remove O2 and install a pressure gauge so you can check back pressure at cruise and WOT].

Oxygenated fuel 5%O2 3-10%Thermostat 3-5%Who knows what else and you can see how you can drop MPG by 20% easily.

I can assure you that most techs are not detailed enough to go looking for MPG problems they just write most off as driver problems or fuel problems.

[AZhitman]

I can assure you that most techs are not detailed enough to go looking for MPG problems they just write most off as driver problems or fuel problems.

That's what I was afraid of. Considering they've made $6000 off Quella and I in the past 18 months, I won't feel bad demanding a closer inspection. Especially after hearing Fred gloat about 18+ mpg in a MODDED Q.

Those guys hate it when I roll in with a handful of Dennis's informative posts.

[wamQ45]

AZ I hope you are planning to drive Quella into the ground....I put a grand into mine and I feel that that is too much for a car that has a market value of 4-5K. I will keep mine to 200K miles at least but I will not put more than another 500 into it (note I did say it and not her).

[PalmerWMD]

wamQ:The marklet value of 4-5 k is for teh "average undermaintained Q".Ours are not like that.Yes we cant sell them for 12k but my litmus test is this:What would I pay for this car on a lot KNOWING WHAT I KNOW ABOUT ITS CONDITION.

For my last Q that was about 13k.

Fred...

[Q45tech]

$500 for another 30,000 miles heck a Civic will cost 8 cents per mile to maintain to spec that's $2400.......you gotta expect to spend more than that...........at least 15 cents per mile for a Q........after the warrant runs out.

What does resale have to do with anything......you just assume the junk yard will give you $1000 at the end.

[wamQ45]

My car is not tech level maintained but it is in good condition. I paid 11000 for it three years ago and it had 124K miles. I have done the under plenum hoses recently. Acording to KBB.com a 94 Q with 174K in good shape will get you $5230 in a private party transaction. The trade-in value from KBB is $3365. I am just saying I am not married to my Q. Would you buy you wife a diamond ring if you knew she was going to leave you in a couple of years no matter what.

[AZhitman]

AZ I hope you are planning to drive Quella into the ground....I put a grand into mine and I feel that that is too much for a car that has a market value of 4-5K. I will keep mine to 200K miles at least but I will not put more than another 500 into it (note I did say it and not her).

Well, I probably overpaid at $13K (in 11/01) at 75K miles for a 95Q45t in pristine (not a single visible flaw) condition. Paid another $1500 for a 3 year/40K mile warranty. The $6000 I mentioned was the warranty company's money, not mine. So all told, I'm into Quella for $15K (she's pretty much paid for). Maintenance costs have been negligible (I have a buddy who does all the maintenance, and a Mobil 1 supplier who keeps me in fresh oil), and .

I plan to consider her condition when the warranty runs out (at 115K). If I can renew the warranty for a reasonable price, I'll keep her. Otherwise, I'll take fair market value from one of the several interested NICO members and I'll go pick up a 2 year old G35 premium sedan.

[Q45tech]

Cars can last forever [women and men wear out] I can assure you most [many] wives and children cost more than cars to maintain......the house, the pool, the college, compared to a $600 extended stay hotel..............don't understand the analogy of buying wife anything she might get killed tomorrow - guess you could get the ring back or insurance.

I can't understand why anyone would even think about resale value on a 10 year old car...........assume its worthless to some one else and keep driving it.........the worse the body looks the more people will avoid getting close to you.... fewer accidents.

Rememeber the modified Lincoln in Animal House now that's a car! painted teeth and flames, a steel gun turret that would change your image on the road. Maybe at work too, less bull if they thought you might terminate them with extreme P.

Kind of like the Hells Angle or Outlaws of the car world.

[maxnix]

Mounting Freeway to Freeway TOW missiles should be cheap once this Gulf adventure is over. Might have to get one of those JDM front fascia to conceal them.

[AZhitman]

Even as pretty as Quella is, I won't hesitate to plow some basturd if circumstances warrant. I've got a sh!tload of insurance, a heavy, well-balanced car, and am no stranger to engaging in intentional vehicular combat (all that training in the Crown Vic paid off).

I like Dennis's "Road Warrior" scenario - My Suburban is set up as such.

I may drive Quella "into the ground" if my mechanic decides to stick around, if the state of AZ continues to keep me in indentured servitude, and if I can find a damn service manual (within reason) sometime soon...

[VimyJ]

Fred, are you still driving around with your Blues Brothers p.a. setup? Quite a bit of aerodynamic drag at highway speeds.

Interesting to see how people value their cars. I tend to see my J as a dissposable asset. I love driving it and learning about it. Yet, I figure that for what is really chump change I can get another one if worse comes to worse. That's not to say that I don't spend some coin maintaining her. The value of this car to me (aside from transportation) is the drivng experience. You get artful performance for a dandy price. Of course, I'm talking about a J30t not an early Q45. There is a maintenance difference of scale.

[RobHakari]

To revive a dead thread.... on a recent 300 mile trip i took, I got 20.1mpg with my new '94 Q... and that was on *gasp* mid-grade gas. i know... i know.... only preium. i didnt know it at the time. i do now

- Robert

[vancouverbc]

http://www.fueleconomy.gov/feg/findacar.htm

premium makes that big a difference in mileage? 28 mpg for my 1991 240 sx is what the gov't says. almost worthwhile to get a new car.

[Q45tech]

Unfortunately EPA published data assumes you drive like their test and not go over 60 mph EVER!

Most mileage compliants stem from people averaging over 55 mph with AC on.Once you get above the rarefied range off 60 all bets are off.70 mph uses 27% more fuel per hour than 55 mph.

Unfortunately the G35 3.5 liters V6 and less economical gearing [to create faster acceleration] [and feel peppy on the road] makes it behave like a 4.0 liter V8 in the gas consumption area..............as the V6 needs to turn 15% more rpms at cruise to equalize.

[DAEDALUS]

That'll be a sight. In 2020, when gas costs $12/gallon, many of the NICO old-timers will be owners of 1st-gen G35s, and they'll be swapping rumors of which rear diff will bolt up for better mileage.

[texasoil]

Q45's should get +/- 20 MPG at a steady 70 with A/C on. If you have a 'nervous foot' and are continually speedig up and slowing down, real easy to knock 5 MPG off that figure.

Some people are comfortable driving a 'maybe it's get there' car on the freeway--that's why there should be much more rigorous condition inspections like they have in Europe. Just because YOU are comfortabe,that doesn't mean its fair to the innocent fellow next to you that gets killed when you break down, swerve, etc.

Houston is loaded with rolling wrecks driven? by undocumented folks--who never before obeyed any traffic laws. Our 'uninsured motorist' insurance now costs 25% as much as our own!--That means 1 out of 4 cars has no insurance, and you can eaily pick them out--but not the cops--that's 'profiling' and unconstitutional.