MAF EVAP Low mileage performance

sergio II · Post by **sergio II** » 22 Sep 2023, 13:28

I have had a long story or struggle with MAF in Volvo [I used to be Sergio with a S60 02) until I lost my email account].
This 2012 S60 T R design, has a very low mileage. Strong smell of gas at the start which dissipates after a while.
I cleaned MAF, ETB, changed the EVAP canister ....still the same.
The following pictures with RPM @ idle, ~2K and ~3k

Can anybody tell what is wrong / not normal here.

I'm lost
"Billions and billions" of thanks - in advance

Post by **regent** » 23 Sep 2023, 06:14

Can you look at your fuel trims; if you've had air leaks and fixed those you may need to reset fuel trims otherwise the car may take a while to re-learn

sergio II · Post by **sergio II** » 23 Sep 2023, 22:14

Thank you regent,
i did the following;
disconnected the battery negative,
unplugged the MAF connector,
waited 30 minutes, (reset the trims?)
reconnected the battery,
started the engine [there was no gas smell at the exhaust] and NO CHECK ENGINE
turned the engine off and reconnected the MAF, re-started the engine,
CHECK ENGINE and Smell came back!
Was my resetting not correct or or is it definitively another $ 400 for a useless new MAF sensor?

on my previous 02 S60, I bought one used, then one new MAF sensor and neither worked. The culprit was some coolant poured om ECM!

Post by **regent** » 25 Sep 2023, 18:23

Sorry I meant resetting with VIDA, not sure if battery disconnect would do. I think they are stored in some sort of NVRAM that does not 'forget' easily :0)

Look in Activations for the ECM in Vehicle Comms and find Fuel and Air something, they are in there somewhere

It's been awhile since I did that and I don't have my laptop with me right now... I've had to reset the trims after I replaced my PCV membrane which had failed and had triggered lean codes because of the unmetered air thus the trims were crazy high

You may want to see the trims' values first before blaming any expensive part. Long term fuel trims should normally be a single digit like 1 or 2 and steady. Short term trims will fluctuate with load and duty

sergio II · Post by **sergio II** » 10 Dec 2023, 16:59

SOLVED
As I refused to AGAIN and AGAIN buy a MAF, I went on exploring everything that crossed my mind.
Meanwhile the hole was becoming larger and larger until one day it allowed a little bit of gas pour out of its neck.
Yes my friends, I'm speaking of the gas tank neck, about 10" below the cap.
Luckily no one had it, not even the dealers (none of them). Back order they said.
And the irony of the outcome was that my DICE got angry and stopped working, I mean stopped dead.
She has a temper (worse than Chinese women) 150~200 dollars and poof.
I can't know what she thinks? But I don't see the engine light.
Maybe it needs a bulb?!

Post by **regent** » 11 Dec 2023, 07:43

Glad you got it sorted