Replaced MAF on C43 question

[AMG KC]

Hi all :)

I just replaced the MAF on my C43, is it quite normal for it to run like a dog straight after that if the original one was questionable?

I havent driven it anywhere yet, im just about to hook the battery back up and see if a reset helps.

Thanks in advance ;)

[vaspen]

by dog you mean bad ? lol it could be a faulty new maf (it happens )

[Pagz]

Hey, Sounds like you may have a leak somewhere!.
Have all the crankcase vent hoses been replaced including the T intersection above the throttle body?,they go hard and leak over time, also while your there replace the seals either side of the 90 degree bend going into the plenum these go slack with time you'll really notice how tight a new one is when you press the maf in,all these new parts are updated and have extra ribs for a better seal. Leaks on any of the crankcase breather pipes will cause rough running as the restrictors are located at the valve cover so anything downstream is unregulated into the plenum when they leak!.

Cheers

[AMG KC]

Sorry for delayed response, i got quite busy after i hooked the battery back up.

I did get a chance to test it though, started like a new car and idled much smoother than it even has before. I havent driven it yet, but it seems as though the computer had learned some bad habbits and needed some time to think about it ;)

[RemoLexi]

Any time you change a component related to air/fuel mixture, the adaptation reset must always be performed.

As parts wear, the fuel mixture adapts to keep the car running its best as much as it can while staying in parameters, once out of parameters it will flag a code. Simply installing a new maf won't fix the issue because the ME is still running mixture adaptation data to constantly remedy a problem which you just fixed by replacing the maf. But the ME doesn't know that!

Clearing check engine or data trouble codes does NOT clear fuel mixture adaptation.

[RemoLexi]

In SDS you have the ability to reset various component adaptation,

For example transmission shift adaption must be done if new transmission is installed. As the clutches wear, the ETC senses slip before you even know a thing, as a remedy (within parameters) it will command the valve body to apply more line pressure to the needed bands to eliminate gear slip. So many cases, installing a new trans but old problems stored, you will think the new trans is no good!!

Throttle body adaptation, (do not perform, ever!) relearns throttle body end stops. Though cleaning the throttle body often times helps engine run smoother ect, never perform throttle adaption reset due to worn throttle plates may sometimes never be able to relearn again, forcing you to replace the unit after causing issues you've never had before.

[AMG KC]

Yeah i just disconnected the battery for 10 minutes and it was perfect after that. I just got back from a drive and its clearly alot better, especially at WOT.

[Pagz]

Remo,Good info on the throttle body, I was contemplating runing the C43's TB think I'll just go with the CLK's one so the ECU has already got it right.

Have you ever done the reset for the CPS?, the one that is ment to be done when changing the engine mounts and CPS etc, it looks like you need to hold the car at about x load window for 30 seconds whilst connected to SDS?(sounds tricky)

wis doesnt spec any reset when doing the maf change unlike nearly everything else?

[RemoLexi]

I don't remember ever having to do that (and I've done hundreds of engine mounts and crank sensors)

[RemoLexi]

WIS is a bit of a pita to use. Startech info was same info but much easier to navigate.

Make sure you only use throttle body cleaner on yours, they are coated and regular brake clean I've been told is too abrasive and can wipe off the coating they have from factory.