Finally got round to using FES to fead the engine fault - MAF Sensor Low Signal...
I have no issues with performance of the engine, MPG etc...
This fault happened after I had to drive through some deep seawater... I cleaned the MAF quickly after that, I've reset the fault and it comes back.. so have I destroyed the MAF, or is it faulty, or does it possibly just need drying out somehow?

It wouldn't take long to dry out on its own with the amount of air the engine draws past the MAF sensor.

Salt water is very corrosive, my guess is you need a new MAF sensor but check and clean its connector as salt water may have corroded that too.

Interestingly when I first got the car, before cleaning the MAF I drove a day or two with it disconnected, and noticed no adverse affects. Does this mean that possibly my MAF has always been goosed? I had engine faults when I got the car, but they cleared themselves. Not had any for eight or nine months up until this.
Would carb cleaner on a cotton bud do for cleaning the conenctor contacts, or would you get some specialist contact cleaner?

I use Halfords electrical contact cleaner(http://www.halfords.com/webapp/wcs/..._productId_195717_langId_-1_categoryId_255223) but I guess carb cleaner would do.

If your car runs the same with or without the MAF sensor connected you probably need a new one.

A good MAF should make the car feel better when its connected.

A bad MAF will make the car feel worse when its connected.

Cheers.
So would you buy a used Bosch MAF or new OEM one, similar price?

why buy used if a new is a similar price?

Because I read somewhere that copy ones at £20 are not as reliable as the Bosch ones at £100

you run the risk of the 2nd hand MAF not being much better than your already knackered one... MAF is a funny one to predict cos i know of 'pattern' parts that work perfectly well on some cars and not on others... get a cheap new one, if it doesnt work take it back, if it does work keep it lol

The Stilo OEM MAF is Bosch ...

Yes, but are the cheap new ones just a waste of money? Can't afford a new Bosch one, so do I go new or used?

If funds are a little sparse buy a used one to solve your problem for now.

Then when you have the funds buy a new OEM part.

Bought the one you PM'd me Shadey...
Be interesting to see if it makes a difference, as like I said, MPG didn't change with or without my current one, and is pretty much the same as other MW JTDs.

£20 for an used OEM part isn't a bad price. It may last you years, there again it may not but atleast it will stop the errors for now giving you time to save for a new OEM part.

Ok, here's an intresting twist.
Since we had sort of agreed that my maf must be duff and considering that last time I disconnected it it had made no difference, I unplugged it before I left work.
Now I was monitoring mpg v speed since my service last week, and jesterday I reset the trip as I got on the M55 and did 12 miles at 60, returning 54mpg. Tonight with the maf disconnected exactly the same journey returned 60 mpg! That's too big a difference to just be a coincidence.

So do I assume that the ecu has a default setting, and that this is more efficient than the setting generated with the faulty maf?

Although I'm not a big fan of assuming (read somewhere that it will make an ass out off U and me), I think you are assuming right.
You should feel a powerdifference too if your MAF is out of whack.

gr J

Interesting and wierd. This morning, performance was pretty much as it normally is, motorway stretch was 53pmg, total work trip around 48. So no difference with or without the MAF, so it definitely isn't working or at least having any positive benefit - but that doesn't explain an unheard of 60mpg last night compared to 54 the night before...

Downhill? Tailwind?

gr J

Exactly the same piece of road at the same speed. Not noticeably different wind.

OK... an update. Bought a second hand MAF off ebay (Thanks Shadey) and fitted it. Also bought a VAGCOM USB lead, and reset the engine fault light uing FES - all cleared now, no faults.
My only regret is not buying the ELM cable instead of the VAGCOM - harder to set up, but I could have reset my service due indicator too!
And I'll never know whether buying a new aftermarket MAF would have been better than a used OEM one.

Further update:
All is running smoothly, and MPG has definitely improved - hard to tell exactly, but I'm getting around 52mpg for my daily round trip compared with around 48 before, do that's a little under 10% improvement... which is a fiver saved on every tankful.
I'm assuming that the new MAF will have a more noticeable affect at higher speeds, when the re is a greater throughput of air for the ECU to manage the mix with? Or am I talking horsepoo as usual?