We just recently had the walnut blasting done to clean the engine out. We were getting an average of 32-33 mpg and then we got an engine light that was for the carbon build up. Our mpg dropped to 27-28 during that time. Now after the walnut blast I was expecting to see my gas mileage go back up, but it has now dropped to 25. Has anyone else had this issue? Will it just take a while for the computer to adjust to things being clean again?

 

Where do you live? Winter blend of gas maybe? Has your commute changed? I've never gotten 33 mpg.

 

What is the name of the shop that did the walnut blasting?

How many miles are on your car?

Did they read all the codes from your car to see what else needed fixing?

 

Yeah winter gas does suck, but we just got the cleaning done and it has dropped since then.

 

I got it done at a Mini dealership. Only codes that it had were related to the carbon build up. Car has just under 75,000 miles

 

Give it a few tanks of gas. It will need to adjust and relearn. Mine did the same thing last year. I think after tank 3 or 4 it leveled out. Didn't gain much but it ran a whole lot better!

 

I believe I read somewhere that the algorithm for projecting range on the amount of gas in the tank, and I'm betting for equating the MPG, is in 14 mile increments.

 

ok, thank you
I asked the dealer if it just needed time to adjust, but they didn't know.

 

So my wife and I took the Mini for a nice long drive yesterday. I thought maybe that would help it out a little. The gas mileage went up to 31.8. I was pretty excited and thought it was getting back to normal. Went out to start it this morning and it started like it did before we had it repaired, and then the engine light came. I don't know what is going on with this thing.

 

Now it is sounding like the High Pressure Fuel Pump has gone bad. 10 yr-120,000 MI warranty on that gem.

 

Just a thought, but did the dealership do a reset? Even if they did you might want to do this so your ECU can relearn your driving habits and adjust.

 

I am taking it in tomorrow, so hopefully I find out what is going on. The fuel pump was replaced at about 30,000 miles I think.

 

Good luck! That sucks... keep us updated!

 

Yikes. I hate it when you get one fix done and another pops up. I had that last year with my water pump and thermostat. One week I replace the water pump. Then the next week the thermostat starts leaking like a sieve.

Good luck! Let us know what they find!

 

I've always wondered why it takes so long to have a code read at a dealer, been here over an hour already. I wish the little handhelds you can buy at the autoparts store worked with the Mini, they take like 10 seconds when they work with your vehicle.

 

Ok, they just basically said they aren't sure what it is. Random misfire codes.....
They said it could be articles of the walnut shells in there burning off still. They wanted to keep the car, but because of my work schedule and the distance from the distance from the dealer I wouldn't be able to pick it up till late next week.
Then they said that the codes were never fully erased from before, so they may just be popping back up. They are going to erase them, and I guess we will see.

 

Reading a codes and diagnosing whats wrong are two different things. You can't diag without codes however (at least not very well or with any ease). Reading codes will direct you to the starting line of diagnosis, but it doesn't tell you exactly whats going on. You can have one or more codes come on for 2 or 3 different reasons. So while yes it is quick and easy to pull codes, knowing why that specific code came on takes some time. The idea is to fix the car the first time. While they could easily throw the most common part in your car for the code that came up, your car may not need that part, but another part that could make the same code come on. Or it could even be an issue in the wiring harness with wires chaffing causing false codes to activate and cause problems.

Its similar to coming on the forum here and searching for an issue. You find a thread from somebody else that has the same thing going on and what they had to do to fix said issue. You go home and do the same thing only to find out you still have the problem.

So long story short, not all cars have the same problem. So they take the time to be sure

 

When I got the codes read initially they told me I needed the walnut blast, spark plugs and an air filter. So I figured I can replace plugs and filter myself and save on parts and labor. I took the plugs out and they looked great. So I asked when I went back for the blast if they actually checked the plugs or filter and they said no, they just say that automatically with a misfire code. They said they didn't even open the hood, just read the codes. So again not sure why it takes so long....

 

To be honest, if they didn't even check then they are not a reputable service center. And maybe thats MINI's policy. Either way its not how a service center should conduct business. The reason to go to the dealer is so they do spend the time to diag your car! This infuriates me! I too would wonder what the hell they were doing for so long too! So for what they say they did should have only taken moments! Not over an hour! They could have told you they needed to keep your car back when they pulled the codes....

Well, *sigh*, keep us updated.

 

So far so good, no cel coming back yet. Gas mileage seems to be up, but not sure exactly where it is at. Better than 25 for sure though.

 

So basically they cleared the codes and said IDK? Well I hope they just screwed up and didn't clear the original codes. And I hope your MPG climbs back up.

 

That's an awful diagnosis.

 

Sometimes you just have believe that the mechanic cleared the codes and drive until another problem shows up.

If the same codes show up again, then the mechanic can go to the next step.

Maybe it would help to also meet with the service manager and let them know how upset you are!

 

So far no more cel. Mileage is between 30-31, not where it was but better than 28. Hopefully still goes up. Car still starts rough and does not like the cold weather though.

 

Got another cel today, not sure what is going on with this thing. There has to be something else wrong with it. Sent dealer an email, and will be calling them this morning.