Terrible mileage since tuneup...

titodj · #1 07-25-2018, 02:15 PM

I can't understand why, but when I bought the car was giving me like 16 MPG

After new spark plugs, air filter and injector cleaning, I'm getting like 14.4 MPG
I don't understand why it went down...

The last air filter was super clogged, but the spark plugs had a bit of carbon buildup, but no so bad.

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andrewwynn · #2 07-25-2018, 02:19 PM

Make sure your temp is getting up to 90°C using the hidden menu. If the tstat is not closing completely you won't get closed loop and mpg will suck

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titodj · #3 07-25-2018, 02:28 PM

Thanks I'll check that !

titodj · #4 07-26-2018, 01:12 PM

The thermostat seems to be working fine (Is new).

Yesterday while waiting for my son I unlocked the secret menu, and the first reading of the temperature was 102, then as I kept waiting for my son, with the car idling dropped to 89, and while driving was around 98.

andrewwynn · #5 07-26-2018, 01:43 PM

That seems like a lot of wandering around. Mines usually within 2° of set temp

titodj · #6 07-26-2018, 02:44 PM

I will check again today, and see how much varies.

fishhouse4 · #7 07-26-2018, 03:15 PM

How long has it been/how much have you driven it since? Did you disconnect the battery when you did the tuneup? If so, that would of reset the MPG.

I recently noticed the same sort of thing after doing some engine work and unplugging my battery. The average reset to something like 12 MPG. Took me driving for several weeks and finally a long trip out of town for it to get back up the 18 MPG calculated average that I was used to seeing.

Just a thought...

titodj · #8 07-26-2018, 03:31 PM

That's a good point.
Yes I disconnected the battery, and it's only been about a month.

Quote:

Originally Posted by fishhouse4

How long has it been/how much have you driven it since? Did you disconnect the battery when you did the tuneup? If so, that would of reset the MPG.
.

andrewwynn · #9 07-26-2018, 10:57 PM

Do some manual calculation. Full tank to full tank and the math of miles. For consistent fill use this method: fill at full speed until shut off, then pause two seconds then fill half speed for one auto shut off.

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titodj · #10 07-26-2018, 11:02 PM

Quote:

Originally Posted by andrewwynn

Do some manual calculation. Full tank to full tank and the math of miles. For consistent fill use this method: fill at full speed until shut off, then pause two seconds then fill half speed for one auto shut off.

What I've done is fill up, and then divide the miles with the gallons in the next fill up.

I'll try your method, thanks !

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