Hey gang! Having an issue here with my 05 R53. Its bone stock with just 29K on the odom. The check engine light was on and I had the code read. It came out as a post cat O2 sensor bad. Replaced it with one I got from a fellow forum member. Cleared the code, and it did the trick. lite went out and has not come back after a week of driving.

Now the problem, my MPG has been hovering around 20 to 21mpg. I keep my foot out of it most of the time, so I am not sure why my mileage got worse. It was stuck at 23.1mpg when the lite was stuck on for a couple months before I got the sensor swapped out. Should be getting like what, 25 to 28?

I ran some injector cleaner through it, Berrymens Chemtool I believe, but still nada. 20mpg.

um... HELP! Where do I go from here?

 

Those are some seriously low miles. What kind of fuel are you running? How long are your trips that you take when you drive? Highway or city? Not saying this is your issue, but some things to check. When's the last time you did some routine maintenance items? Such as filters, plugs, etc?

https://www.reddit.com/r/MINI/commen...etting_better/
http://www.mini2.com/forum/first-gen...hat-gives.html
https://www.northamericanmotoring.co...-r53-mini.html

 

The ECU only uses the input from the o2 sensors in cruise....
WOT uses maps in the ECU....
Secondly, the FORWARD o2 sensor is the one the ECU uses to lean the mixture in cruise...
The rear most one, the one you replaced, ONLY MONITORS THE effectiveness of the cat...
So changing rear o2 sensor will do nothing to improve your mpg....
And if you have a pretty fancy odb2 pro-grade tool, when you reset the computer, you reset the adaptations, this COULD have lowered you mpg.... It typically takes 2-3 tanks of fuel to recover your lost mpg after adaptations are reset.
Low mpg is usually the result of driving style... "Keeping YOUR foot in it" usually results in less than 25 mpg...so sounds normal....
Mostly highway, cruise on can get you closer to 28-30 at reasonable speeds....
Heavy rims (s-lights, typical 17 rims) and wide tires, with lots of braking all kill mpg, as does "keeping your foot in it"....
So sounds pretty normal IMO.
And one tip...." Injector cleaner" is usually a "light petroleum solvent", aka #1 DIESEL fuel, sometimes with a few extra chemicals added....the main thing it does is lowers octane of your fuel...adding injector cleaner with fuels with high ethanol content is kinds like adding dry gas to it, generally a total waste of cash, since the ethanol is an effective solvent itself, and it absorbs water....
Hate to sound harsh, but if you are gonna drive hard, low mpg and high repair bills are all par for the course.

 

HA! A FELLOW ZIPPY! Wow guys! Seriously well thought out questions and answers. Major kudos to you both!

Pelican: I got the car (my second R53) from an elderly woman in the Seattle area. It was a purchase she made to save money on her trips into the city but she didnt like dealing with the clutch, so they just took her fancy lincoln town car instead and the mini just sat all the time. Thus the very low 29K miles on an 05 R53. Amazing right?! The interior is like a time capsule from 2005. Brand spanking new. Exterior needs some trim and very light body works but yeah, amazing find. Picked it up for $8900.

Okay, so to answer you questions, I drive it 15 minutes each way to work with a slight mix of 55mph and some 25mph city driving in that commute each day. It doesnt see much else. I use only premium gas here in Oregon. I havent done the filter and plugs yet, but I am planning on that next along with the 15% pulley colder plugs and intake, likely from Madness Motorworks in Hillsboro oregon.

Zippy: Man! You are like the wikipedia of the Mini world! Minipedia! Great info my friend. It has only had one take through it since I replaced the post cat O2. The light did stay off now though, so you are very likely spot on with your thinking here, it probably just needs time to fuller recover. I do not own an OBD2 reader, but I had the local autoworks do the light reset for me after I finished the swap out.

Thanks again guys! This was far more than I expected!

 

Day 1.





This is from the day I got it.<br/>

This is what I have done so far. Wheels, tint, and new side markers. Just getting started of course. Not going black out this time around though. Going for a more vintage/mix look.





2 months in. Great start!

 

Oh, Pelican! Do you guys offer a discount if a guy orders all the wheel arch trims and rocker rails for the whole car in one order?

 

Unfortunately we don't have a discount for that right now. However, I see that you'll be ordering an intake and pulley from Madness Motorworks and we are having a 10% off deal on their products right now until May 1st. That way it'll save you some cash for those items if you're interested! Details on our promo page here: http://www.pelicanparts.com/cgi-bin/promos/. You can also check that page for updates as we constantly run promotions each month. Digging the wheels BTW!

 

Thanks! I will check it out! Can hardly wait to get this lil pup to where my first R53 was! Love the Mini. Will never sell this one. Ever.

 

Very nice 1Zippy. Just picked up an '04 R53 with 79,000 miles on it, in Portland.

 

It is a great color isnt it? Seems like most folks go with the blackout on the pure silver, I did last time with my 06, but this time I am going to go for a more classic look. How about you guys?

 

Blacked out gets old...so many are that way...
I kinda liked the chrome since the MINI's desgin is in hommage to a classic....

 

Agreed! Although, I am also thinking of going with a vinyl stripe. I want to keep it classic lined, so two on the bonnet, two on the boot to match. MIGHT go with on the roof but I have a sunroof sooooo, yeah, not to sure just yet.

I have yet to see a single 1st gen, or any other gen really, with the dual gradient stripe from might stripes. Thinking I will give it a go with gloss black on the bonnet and boot, and maybe the silver to match on the roof too, but never did vinyl over sunroof so I am not too sure.

 

This, only I have the sunroof so I dunno about the top just yet. Black gloss on bonnet, black gloss on boot, with silver body color match on roof.

 

The silver is a great color, and on the couple days we had of 80+ degree weather (back to chilly now) the tint really helped keep the interior cool. Love the idea of the black hood and boot, plus the yellow stripes. (My original racing Mini was yellow). Definitely want to see pix when you do it!

 

Oops, yeah I will do black on the bonnet and boot, but silver on the roof IF, I go this route. Still undecided on the stripes in fact. Might do the double viper again like last time. It look awesome. My concern with these gradient stripes is keeping the lines straight with each and every piece. Plus, having all those small pieces means more to possibly fail and fall off. Not sure yet.