MAF Sensors (Again)

[dr. benway]

Hi all,

This is my first post on the forum, though I've been reading for a while.

I've suspected my MAF is on its way out for a while--mostly lumpy acceleration, then recently rough idling (the revs dropped but the ECU seemed to kick in and up the revs, before dropping again. Yo-yo-ing seems to be the best way to describe it). As an experiement I disconnected the MAF and took the car for a quick spin; things seemed to be a little bit better performance-wise, though I couldn't really tell to be honest with you. The rough idling did seem to disappear, though.

After the drive I opened the bonnet back up and reconnected the engine, then turned it back on. At this point the engine idling noticeably roughly before stalling. Oops! I turned the engine back on and this time helped the idling with my foot on the pedal--after a couple of seconds of that the ECU seemed to be happy to take over as it was doing before, but I'm a bit worried now.

I've ordered a new MAF from VW but it won't be here until Monday. In the meantime, should I be worried about the car stalling? Or did the brief spell without the MAF confuse the ECU enough to cause the stall when it was re-connected, and it's adapted to the dodgy MAF again and should be okay?

One more question: when the new MAF arrives is it worth disconnecting the battery for a while so the ECU "forgets" any dodgy settings from the old MAF?

Cheers chaps.

[topher]

You won't really break anything if you drive it until monday.. when the signal from the maf is out the ECU will just run default values (same as unplugging the maf) until the signal is in range again.
Should be right as rain when you plug the new unit in. In the mean time I would suggest you give your throttle body a clean if you haven't already.

[dr. benway]

Thanks for the advice, topher. I've never cleaned the throttle body (only really just getting into all this maintenance lark) and I imagine it's not been touched in the last 7 years so must be fairly gunked up in there. I'll give it a go over the weekend.

[dr. benway]

Update for you all: cleaned the throttle body out yesterday--it wasn't as bad as I expected but still a bit filthy. Also stuck half a bottle of redex in the tank, and she's running a lot more smoothly, especially in the low end.

MAF sensor came today too, but to be honest it seems like a new car already. No more rough idling etc. Don't know if the existing MAF has sprung back to life or it's gone completely and the ECU's ignoring it. Either way if it stays sunny I'll go out this afternoon and plug the new one in. Stingy dealer insisted I'd have to book in for it fitting... I'm sure they'd love to charge me for the privilege, too.

[alex160]

dont let them fit it for you mate, its a 2min job to do yourself.

[dr. benway]

Aye, ended up doing it myself--would rather have had the dealers do it for free though

[topher]

i never thought to ask originally, is yours a 1.8T or 2.0? the mention of redex made me ask, the 2.0 seems to need a dose of it now and again.

[dr. benway]

It's a 1.8T. Can't say for sure whether it's the TB clean, redex or MAF that's made the difference but I'm not questioning it either way! 

[topher]

Then it's all fixed and ready for modifications

[dr. benway]

Exactly. Putting some money aside then I think it's on the phone to R-Tech...