The BMW E30 318iS Resource

Fuel Economy Log

This page contains an almost complete history of my car's fuel economy. Data from October 2005 to February 2008 was lost a number of years ago, and the information from that period has been extrapolated as one large entry from all of the data gathered after that period. You may also notice that my 318iS' fuel economy shows an overall decrease after late 2008. At that time I moved to a different location, closer to my office. That enabled me to ride my bike to work almost every day. Because of this, the times that I drove the car were usually for very short distances and errands, so fuel economy suffered overall. Prior to my move, I would drive ~45 miles on the highway daily. Another factor in my decreased mileage was a wiring "oops" when I first bought the car, and the wide-band O2 sensor system I had installed. In short, the fuel injection electronics were only getting about 7V instead ov 12V thanks to a sloppy wiring repair. The wide-band O2 sensor system was also improperly grounded, which caused the ECU to run things pretty rich. Thankfully, all of that was sorted out around May of 2011 and the car seems to run very well now.

The car can still attain 30-32 MPG on long highway drives if I keep the speed under 75mph, but road trips are typically done in my fiancee's Honda Civic since it can easily get 38-44 MPG on the highway. If I drive tamely around town running errands and such, the car usually gets 25-27 MPG. The two plots below give a graphical depiction of the car's fuel economy over the years, and the price of gasoline in the San Francisco Bay area of California.

All fill-ups used 91 octane "premium" gasoline.

2011

Date
Trip Miles
Gallons Purchased
Fuel Economy
Fuel Cost
Fill-Up Cost
Brand
Odometer

5/29/2011
295 mi
12.253 gal
24.1 MPG
$4.239 / gal
$51.94
Union 76
212023 mi

5/15/2011
282 mi
11.866 gal
23.8 MPG
$4.399 / gal
$52.20
Union 76
211728 mi

5/8/2011
317 mi
11.744 gal
27.0 MPG
$4.539 / gal
$53.31
Chevron
211446 mi

5/5/2011
293 mi
12.431 gal
23.6 MPG
$4.439 / gal
$55.18
Chevron
211129 mi

4/23/2011
294 mi
12.539 gal
23.4 MPG
$4.579 / gal
$57.42
Chevron
210836 mi

4/11/2011
324 mi
12.490 gal
25.9 MPG
$4.539 / gal
$56.69
Chevron
210542 mi

4/7/2011
308 mi
12.201 gal
25.2 MPG
$4.499 / gal
$54.89
Chevron
210218 mi

3/27/2011
251 mi
9.670 gal
26.0 MPG
$4.399 / gal
$42.54
Chevron
209910 mi

3/14/2011
318 mi
12.400 gal
25.6 MPG
$4.239 / gal
$52.56
Chevron
209659 mi

3/6/2011
314 mi
12.320 gal
25.5 MPG
$4.219 / gal
$51.98
Chevron
209341 mi

2/19/2011
319 mi
12.343 gal
25.8 MPG
$3.799 / gal
$46.89
Chevron
209027 mi

2/6/2011
305 mi
11.864 gal
25.7 MPG
$3.759 / gal
$44.60
Chevron
208708 mi

1/30/2011
307 mi
12.468 gal
24.6 MPG
$3.299 / gal
$41.13
Union 76
208403 mi

1/17/2011
300 mi
12.390 gal
24.2 MPG
$3.699 / gal
$45.83
Chevron
208096 mi

1/3/2011
303 mi
12.105 gal
25.0 MPG
$3.519 / gal
$42.60
Union 76
207796 mi

2010

Date
Trip Miles
Gallons Purchased
Fuel Economy
Fuel Cost
Fill-Up Cost
Brand
Odometer

12/23/2010
287 mi
11.898 gal
24.1 MPG
$3.539 / gal
$42.11
Chevron
207493 mi

12/13/2010
305 mi
12.849 gal
23.7 MPG
$3.619 / gal
$46.50
Chevron
207206 mi

12/5/2010
275 mi
11.726 gal
23.5 MPG
$3.619 / gal
$42.44
Chevron
206901 mi

11/24/2010
317 mi
11.768 gal
26.9 MPG
$3.359 / gal
$39.53
Union 76
206626 mi

11/19/2010
323 mi
11.870 gal
27.2 MPG
$3.479 / gal
$41.30
Valero
206309 mi

11/10/2010
341 mi
12.535 gal
27.2 MPG
$3.499 / gal
$43.86
Chevron
205986 mi

10/30/2010
272 mi
11.457 gal
23.7 MPG
$3.339 / gal
$38.25
Shell
205645 mi

10/14/2010
327 mi
11.699 gal
28.0 MPG
$3.359 / gal
$39.30
Union 76
205373 mi

10/2/2010
350 mi
11.358 gal
30.8 MPG
$3.259 / gal
$37.02
Shell
205046 mi

9/26/2010
407 mi
13.237 gal
30.7 MPG
$3.039 / gal
$40.23
T.A.
204696 mi

9/24/2010
300 mi
10.926 gal
27.5 MPG
$3.299 / gal
$36.04
Chevron
204289 mi

9/23/2010
349 mi
12.785 gal
27.3 MPG
$3.159 / gal
$40.39
Chevron
203989 mi

9/5/2010
350 mi
12.271 gal
28.5 MPG
$3.299 / gal
$40.48
Union 76
203640 mi

8/31/2010
338 mi
12.429 gal
27.2 MPG
$3.379 / gal
$42.00
Chevron
203290 mi

8/14/2010
292 mi
11.453 gal
25.5 MPG
$3.519 / gal
$40.30
Chevron
202952 mi

8/4/2010
309 mi
12.654 gal
24.4 MPG
$3.369 / gal
$42.63
Union 76
202660 mi

7/24/2010
322 mi
12.121 gal
26.6 MPG
$3.299 / gal
$39.99
Union 76
202351 mi

7/16/2010
457 mi
17.632 gal
25.9 MPG
$3.499 / gal
$61.69
Chevron
202029 mi

7/3/2010
428 mi
15.898 gal
26.9 MPG
$3.519 / gal
$55.95
Chevron
201572 mi

6/25/2010
242 mi
8.805 gal
27.5 MPG
$3.299 / gal
$29.05
Chevron
201144 mi

6/19/2010
329 mi
11.172 gal
29.4 MPG
$3.359 / gal
$37.53
Chevron
200902 mi

6/18/2010
223 mi
8.553 gal
26.1 MPG
$3.499 / gal
$29.93
Chevron
200573 mi

6/11/2010
307 mi
11.539 gal
26.6 MPG
$3.419 / gal
$39.45
Chevron
200350 mi

6/2/2010
306 mi
12.321 gal
24.8 MPG
$3.379 / gal
$41.63
Chevron
200043 mi

5/21/2010
287 mi
11.225 gal
25.6 MPG
$3.259 / gal
$36.58
Chevron
199737 mi

5/16/2010
296 mi
11.580 gal
25.6 MPG
$3.319 / gal
$38.43
Union 76
199450 mi

5/8/2010
303 mi
11.778 gal
25.7 MPG
$3.219 / gal
$37.91
Arco
199154 mi

5/1/2010
348 mi
12.131 gal
28.7 MPG
$3.479 / gal
$42.20
Chevron
198851 mi

4/25/2010
250 mi
9.283 gal
26.9 MPG
$3.419 / gal
$31.74
Chevron
198503 mi

4/17/2010
336 mi
12.176 gal
27.6 MPG
$3.399 / gal
$41.39
Shell
198253 mi

4/11/2010
284 mi
11.293 gal
25.1 MPG
$3.319 / gal
$37.48
Chevron
197917 mi

4/3/2010
313 mi
12.286 gal
25.4 MPG
$3.419 / gal
$42.01
Chevron
197633 mi

3/15/2010
344 mi
11.947 gal
28.8 MPG
$3.419 / gal
$40.85
Chevron
197321 mi

3/13/2010
212 mi
8.905 gal
23.8 MPG
$3.419 / gal
$30.45
Chevron
196977 mi

3/6/2010
313 mi
12.144 gal
25.8 MPG
$3.419 / gal
$41.52
Chevron
196765 mi

2/27/2010
295 mi
11.980 gal
24.6 MPG
$3.339 / gal
$40.00
Chevron
196451 mi

2/16/2010
309 mi
12.240 gal
25.2 MPG
$3.219 / gal
$39.40
Chevron
196156 mi

2/7/2010
307 mi
11.599 gal
26.5 MPG
$3.279 / gal
$38.03
Chevron
195847 mi

1/24/2010
314 mi
12.609 gal
24.9 MPG
$3.159 / gal
$39.83
Chevron
195246 mi

1/17/2010
304 mi
12.045 gal
25.2 MPG
$3.339 / gal
$40.22
Chevron
194932 mi

1/10/2010
291 mi
11.375 gal
25.5 MPG
$3.759 / gal
$42.76
Valero
194628 mi

1/5/2010
287 mi
11.820 gal
24.3 MPG
$3.399 / gal
$40.18
Chevron
194337 mi

2009

Date
Trip Miles
Gallons Purchased
Fuel Economy
Fuel Cost
Fill-Up Cost
Brand
Odometer

12/27/2009
317 mi
12.043 gal
26.3 MPG
$3.119 / gal
$37.56
Union 76
194050 mi

12/24/2009
303 mi
11.607 gal
26.1 MPG
$3.239 / gal
$37.60
Chevron
193733 mi

12/23/2009
99 mi
3.856 gal
25.5 MPG
$3.399 / gal
$13.11
Chevron
193430 mi

12/23/2009
298 mi
11.957 gal
24.9 MPG
$3.299 / gal
$39.45
Chevron
193331 mi

12/21/2009
300 mi
12.556 gal
23.9 MPG
$3.239 / gal
$40.67
Chevron
193034 mi

12/9/2009
326 mi
12.772 gal
25.5 MPG
$3.239 / gal
$41.37
Chevron
192734 mi

11/28/2009
308 mi
10.859 gal
28.4 MPG
$3.099 / gal
$33.65
Union 76
192408 mi

11/26/2009
385 mi
15.979 gal
24.1 MPG
$3.239 / gal
$51.76
Chevron
192100 mi

11/16/2009
301 mi
12.217 gal
24.6 MPG
$3.299 / gal
$40.30
Chevron
191715 mi

11/7/2009
329 mi
12.191 gal
27.0 MPG
$3.219 / gal
$39.24
Union 76
191414 mi

10/30/2009
334 mi
12.041 gal
27.7 MPG
$3.259 / gal
$39.24
Union 76
191085 mi

10/19/2009
342 mi
12.155 gal
28.1 MPG
$3.279 / gal
$39.86
Union 76
190751 mi

10/13/2009
314 mi
11.608 gal
27.1 MPG
$3.259 / gal
$37.83
Union 76
190410 mi

10/10/2009
289 mi
11.558 gal
25.0 MPG
$3.219 / gal
$37.21
Chevron
190095 mi

10/4/2009
325 mi
12.003 gal
27.1 MPG
$3.319 / gal
$39.84
Union 76
189806 mi

9/21/2009
309 mi
12.115 gal
25.5 MPG
$3.459 / gal
$41.91
Chevron
189481 mi

9/7/2009
342 mi
12.767 gal
26.8 MPG
$3.329 / gal
$42.50
Union 76
189172 mi

8/30/2009
338 mi
12.176 gal
27.7 MPG
$3.299 / gal
$40.17
Valero
188830 mi

8/24/2009
330 mi
12.017 gal
27.5 MPG
$3.259 / gal
$39.16
Union 76
188943 mi

8/16/2009
346 mi
12.455 gal
27.8 MPG
$3.339 / gal
$41.59
Union 76
188163 mi

8/8/2009
319 mi
11.823 gal
27.0 MPG
$3.339 / gal
$39.48
Chevron
187816 mi

8/3/2009
316 mi
11.724 gal
26.9 MPG
$3.279 / gal
$38.44
Chevron
187497 mi

7/26/2009
316 mi
12.075 gal
26.2 MPG
$3.159 / gal
$38.14
Chevron
187182 mi

7/18/2009
310 mi
11.778 gal
26.4 MPG
$3.239 / gal
$38.15
Valero
186865 mi

7/6/2009
306 mi
11.673 gal
26.2 MPG
$3.239 / gal
$37.81
Chevron
186555 mi

6/21/2009
319 mi
11.107 gal
28.7 MPG
$3.249 / gal
$36.09
Union 76
186249 mi

6/14/2009
335 mi
12.057 gal
27.7 MPG
$3.199 / gal
$38.57
Valero
185930 mi

6/8/2009
313 mi
11.118 gal
28.2 MPG
$3.199 / gal
$35.57
Chevron
185595 mi

6/4/2009
322 mi
12.130 gal
26.5 MPG
$3.099 / gal
$37.59
Union 76
185282 mi

5/26/2009
362 mi
12.444 gal
29.1 MPG
$2.979 / gal
$37.07
Chevron
184960 mi

5/23/2009
292 mi
10.794 gal
27.0 MPG
$2.999 / gal
$32.37
Shell
184599 mi

5/15/2009
343 mi
11.845 gal
29.0 MPG
$2.839 / gal
$33.63
Chevron
184307 mi

5/8/2009
302 mi
10.909 gal
27.7 MPG
$2.779 / gal
$30.32
Shell
183964 mi

4/28/2009
341 mi
11.725 gal
29.1 MPG
$2.639 / gal
$30.94
Chevron
183661 mi

4/25/2009
343 mi
11.862 gal
28.9 MPG
$2.599 / gal
$30.83
Shell
183320 mi

4/15/2009
339 mi
12.263 gal
27.6 MPG
$2.549 / gal
$31.26
Union 76
182978 mi

4/9/2009
321 mi
11.259 gal
28.5 MPG
$2.659 / gal
$29.94
Chevron
182639 mi

4/4/2009
348 mi
12.154 gal
28.6 MPG
$2.539 / gal
$30.86
Union 76
182318 mi

3/29/2009
346 mi
11.463 gal
30.2 MPG
$2.419 / gal
$27.73
Union 76
181970 mi

3/26/2009
342 mi
12.385 gal
27.6 MPG
$2.539 / gal
$31.45
Chevron
181623 mi

3/8/2009
315 mi
11.106 gal
28.3 MPG
$2.519 / gal
$27.98
Chevron
181281 mi

2/27/2009
420 mi
14.888 gal
28.2 MPG
$2.539 / gal
$37.80
Chevron
180966 mi

2/20/2009
326 mi
12.174 gal
26.8 MPG
$2.599 / gal
$31.64
Union 76
180546 mi

2/9/2009
334 mi
12.351 gal
27.0 MPG
$2.439 / gal
$30.12
Rotten Robbie
180220 mi

1/31/2009
349 mi
12.685 gal
27.5 MPG
$2.339 / gal
$29.67
Union 76
179887 mi

1/25/2009
350 mi
12.492 gal
28.0 MPG
$2.259 / gal
$28.22
Valero
179538 mi

1/18/2009
339 mi
12.053 gal
28.2 MPG
$2.299 / gal
$27.71
Chevron
179188 mi

1/10/2009
329 mi
12.394 gal
26.6 MPG
$2.339 / gal
$28.99
Chevron
178848 mi

1/4/2009
330 mi
10.589 gal
31.2 MPG
$2.499 / gal
$26.46
Shell
178519 mi

1/4/2009
286 mi
9.700 gal
29.5 MPG
$2.059 / gal
$19.97
Chevron
178189 mi

1/1/2009
412 mi
14.922 gal
27.6 MPG
$2.999 / gal
$44.75
Mobil
177903 mi

2008

Date
Trip Miles
Gallons Purchased
Fuel Economy
Fuel Cost
Fill-Up Cost
Brand
Odometer

12/31/2008
281 mi
10.059 gal
28.0 MPG
$2.119 / gal
$21.32
Union 76
177491 mi

12/22/2008
326 mi
12.474 gal
26.1 MPG
$2.179 / gal
$27.18
Shell
177209 mi

12/13/2008
323 mi
11.208 gal
28.8 MPG
$1.899 / gal
$21.28
Valero
176884 mi

12/5/2008
355 mi
12.639 gal
28.1 MPG
$2.079 / gal
$26.28
Union 76
176561 mi

11/24/2008
308 mi
11.292 gal
27.3 MPG
$2.279 / gal
$25.73
Rotten Robbie
176185 mi

11/16/2008
332 mi
12.136 gal
27.3 MPG
$2.539 / gal
$30.81
Union 76
175877 mi

11/3/2008
335 mi
11.415 gal
29.3 MPG
$3.219 / gal
$36.74
Union 76
175545 mi

10/25/2008
325 mi
11.867 gal
27.4 MPG
$3.599 / gal
$42.71
Chevron
175210 mi

10/13/2008
344 mi
11.898 gal
28.9 MPG
$3.869 / gal
$46.03
Shell
174884 mi

10/4/2008
276 mi
9.953 gal
27.7 MPG
$3.859 / gal
$38.41
Valero
174540 mi

9/29/2008
290 mi
9.933 gal
29.2 MPG
$3.899 / gal
$38.73
Rotten Robbie
174264 mi

9/22/2008
341 mi
10.790 gal
31.6 MPG
$3.899 / gal
$42.07
Rotten Robbie
173974 mi

9/14/2008
323 mi
10.343 gal
31.2 MPG
$3.999 / gal
$41.36
Rotten Robbie
173663 mi

9/12/2008
340 mi
10.962 gal
31.0 MPG
$4.176 / gal
$45.78
Union 76
173310 mi

9/5/2008
346 mi
10.663 gal
32.4 MPG
$4.059 / gal
$43.28
Rotten Robbie
172971 mi

8/30/2008
357 mi
11.874 gal
30.0 MPG
$4.099 / gal
$48.67
Rotten Robbie
172625 mi

8/23/2008
335 mi
10.673 gal
31.4 MPG
$4.279 / gal
$45.67
Union 76
172269 mi

8/20/2008
349 mi
11.990 gal
29.1 MPG
$4.279 / gal
$51.31
Union 76
171933 mi

8/11/2008
261 mi
10.022 gal
26.1 MPG
$4.339 / gal
$43.49
Rotten Robbie
171584 mi

8/3/2008
348 mi
11.582 gal
30.1 MPG
$4.399 / gal
$50.95
Rotten Robbie
171323 mi

7/17/2008
360 mi
11.678 gal
30.8 MPG
$4.599 / gal
$53.71
Rotten Robbie
170975 mi

7/10/2008
352 mi
11.534 gal
30.5 MPG
$4.639 / gal
$53.51
Rotten Robbie
170615 mi

7/4/2008
344 mi
11.598 gal
29.6 MPG
$4.699 / gal
$54.50
Rotten Robbie
170263 mi

6/28/2008
292 mi
10.351 gal
28.2 MPG
$4.779 / gal
$49.47
Valero
169919 mi

6/3/2008
322 mi
10.502 gal
30.6 MPG
$4.499 / gal
$47.25
Union 76
169627 mi

5/28/2008
328 mi
11.683 gal
28.1 MPG
$4.359 / gal
$50.93
Union 76
169306 mi

5/22/2008
329 mi
10.886 gal
30.2 MPG
$4.239 / gal
$46.15
Union 76
168978 mi

5/16/2008
301 mi
10.367 gal
29.0 MPG
$4.219 / gal
$43.74
Union 76
168648 mi

5/9/2008
349 mi
12.298 gal
28.3 MPG
$4.179 / gal
$51.39
Union 76
168348 mi

5/3/2008
335 mi
12.402 gal
27.0 MPG
$4.099 / gal
$50.84
Shell
167999 mi

4/25/2008
339 mi
12.141 gal
27.9 MPG
$4.059 / gal
$49.28
Rotten Robbie
167664 mi

4/20/2008
313 mi
11.188 gal
27.9 MPG
$4.159 / gal
$46.53
Valero
167325 mi

4/13/2008
345 mi
12.078 gal
28.6 MPG
$3.959 / gal
$47.82
Rotten Robbie
167013 mi

4/10/2008
318 mi
10.933 gal
29.1 MPG
$3.959 / gal
$43.28
Rotten Robbie
166667 mi

4/4/2008
361 mi
13.043 gal
27.7 MPG
$3.919 / gal
$51.12
Union 76
166350 mi

3/23/2008
330 mi
11.786 gal
28.0 MPG
$3.949 / gal
$46.54
Union 76
165991 mi

3/11/2008
331 mi
11.850 gal
27.9 MPG
$3.979 / gal
$47.15
Union 76
165661 mi

3/7/2008
315 mi
11.912 gal
26.5 MPG
$3.889 / gal
$46.33
Union 76
165331 mi

2/29/2008
313 mi
11.293 gal
27.7 MPG
$3.839 / gal
$43.35
Union 76
165016 mi

10/2005 - 2/2008

Date
Trip Miles
Gallons Purchased
Fuel Economy
Fuel Cost
Fill-Up Cost
Brand
Odometer

10/10/2005
24616 mi
906.266 gal
27.2 MPG
$2.759 / gal
$2500.39
(Various)
140400 mi