visatrade

iTrader: (2)

I warm my car up every morning and before I go home from work. But really? I only drove 43 miles on 4.6 gallons. I generally allow it to warm up for around 5 minutes or until the temperature needle gets above the two lines above cold. I did this about 6 times over 3 days and drove 43 miles. I had a full tank and I may have accelerated a little fast a few times (Due to idiot drivers or Priuses attempting to drag race) but is this fuel economy normal for the S5?

I passed California emissions test and the test said I did great.

What can I do besides the Throttle Position Sensor and Timing adjustment to get better fuel economy?

I haven't noticed the tank releasing pressure lately when I take the cap off but it has done that before for a while and it came back when my tank was almost dry and I kept filling it only a quarter tank. I am keeping my tank full these days.

jackhild59

iTrader: (7)

You are burning more gas parked than driving. No need to do this.

Why don't you just pretend that it is a *car* and drive it?

clokker

iTrader: (2)

I have daily driven a '91na for seven years now and the only "warm up" it gets is the amount of time it takes to fasten the seatbelt, light a cigarette and put her in first.
I keep her below 3k rpm for the first mile or two and then it's go-time.

The car is fully emission compliant and driven at altitude.
Last couple of months I've been averaging 20.5mpg in mixed driving.

j9fd3s

iTrader: (3)

0mpg right there

ddawson

I get 10 MPG on my 3 mile commute though 6 stop lights.

On my trip up to Lake Tahoe 22 MPG and on the way back to the bay area 23 MPG.

Evil Aviator

Assuming you averaged 43 mph when driving...

Time enroute: 43 mi / 43mph = 60 minutes
Time idle: 5 min x 6 = 30 minutes

Regardless of fuel, 1/3 of your time was wasted for no reason.

Are you measuring the mileage by filling up the tank and comparing the gallons to the odometer?

Keeping the tank full will help avoid getting water/condensation in the tank.

bumpstart

there is an air bypass on the s5 afm you can use to lean down the idle a little

meanwhile a new o2 sensor wont hurt .. a quick check to make sure the coolant sensor is in range
and also a double check to make sure stuff like 5th gear and neutral switches are working correctly down at the gearbox

Tui

iTrader: (2)

All of the above. Good basic stuff.

lastphaseofthis

iTrader: (8)

Fixed.

visatrade

iTrader: (2)

Well I drove on a road trip thing last night. I had a full tank and still had 3/8 at around 250 miles driven. I guess my car just really likes freeways. My drivetrain is all fubar though and after getting lost in San Francisco for 3 hours (I forgot Lombard was the way out) I need brakes as well. Did you know that Golden Gate Ave. doesn't actually lead to the Golden Gate? I had a feeling that was the case.

visatrade

iTrader: (2)

3 miles and you need a car? Have you ever considered a Goped? They have a weed whacker engine that gets over 100 MPG. Also, they fold up for easy storage. I think 3 miles is probably Bicycle range if you have roads that allow it where you live. Unless you are like me. Are so damn beat up and tired after work that you can't even lift a finger when you get home and end up passing out in ten minutes.

visatrade

iTrader: (2)

I took my RX7 for a spin last night to go get fastfood because it was 2am, I don't have any food good enough for a midnight snack, and my stomach was making empty noises.

At 2am I started my car and I took your advice. Upon backing up, the car died. I got to the ramp out of the driveway. It died again. I got down the street and hit the stop sign and it died again.

I may have a bad alternator or maybe something else is screwed up. Point is, when I let it sit and idle until it hits the cold mark, It doesn't die and hasn't since I had gotten it smogged.

It used to do this as well when I didn't warm it up but I didn't put the electricity under load and it would still die. I turned the headlights and the heater off and it didn't die.

clokker

iTrader: (2)

Sounds like the thermowax is out of whack.

rotarygod

iTrader: (1)

Things like this can be tough to fix. It is entirely possible that the cat is going out enough to hurt mileage and performance yet still allow you to pass emissions. I've had that happen. I'm not saying that's it but the point is that it isn't always obvious.

visatrade

iTrader: (2)

Well, my cat (at least defiantly the precat) glows red after long trips. I think it is an S4 cat as well. Which is apparently different.

As far as the thermo wax goes, I will need a bendable camera to see anything that is happening that deep in the throttle body while the car is running.

lduley

iTrader: (1)

If your cat is glowing red after a drive, its plugged, get it off before you burn your car down

rotarygod

iTrader: (1)

Your cat should not glow!

jjwalker

I am going to add this..

You have a gas mileage selector and a gas mileage pedal. I won't go into super detail here as it should be rather self explanatory, but I can explain further if you ask for it.

An engine operating at the highest manifold vacuum at the lowest RPM to keep a certain given speed, is going to get the best gas mileage.

rotarygod

iTrader: (1)

10 mpg cruising is a problem that is not related to the gas pedal. He needs to change the cat.

jjwalker

I meant aside from the glowing cat.

visatrade

iTrader: (2)

It should be a fairly new cat. I heard my EGTemperature was way too hot. Is there any thing I can do to lower the Exhaust Gas Temperature? It was turning a straight pipe purple. I know RX7's have around 2000 Degrees Fahrenheit but I am thinking I may be hotter then even that. I am also missing the heat shields over the cat. Honestly I am more concerned about the drivetrain and suspension at the moment. I don't think it would be a good idea to do backroad driving and that is how I typically have fun after a hard day at work.

TonyD89

iTrader: (10)

Cats also glow from raw fuel entering them (misfiring, running on one rotor). This will destroy the cat, even a brand new one, if it hasn't already.

j9fd3s

iTrader: (3)

i put an EGT on a nice running S5 vert, and the hottest i could get it was 720C/1330F, the factory tune needs to limit EGT to keep the cat from melting

a performance application can have 2000 degree egt's, the RB bonneville car ran 2100 degrees, it also blew up twice.

so if you are getting the exhaust to glow there is something wrong, might be time to check timing?

visatrade

iTrader: (2)

UPDATE: I just drove a ways on the freeway on the third. I filled the tank the day before (Painstaking $60). Roxanne used 7.719 gallons to drive 126 miles. So that is better but a lot of it was freeway some of it was backroad. 16.32MPG (126 divided into 7.719). I still haven't done anything to the engine. Like I said I am much more concerned about the drivetrain at the moment. I just forked out $44.01 for 3 quarts of MT-90. I am considering installing a new throw out bearing (maybe Clutch) at the same time while doing the fluid.

Also, Does anyone know if I have to remove the transmission oil to replace the clutch? What about removing to replace the shifter? My Haynes shop manual doesn't say anything about it.

ibeljin

iTrader: (1)

i may be wrong but im pretty sure the tranny oil would leak out the rear where the driveshaft connects up to the tranny. I drained my fluids when pulling the tranny instead of finding out and making a mess.

Wouldnt be a bad time to put fresh fluid in if its never been changed, it can make a noticeable difference in the way the car shifts