Can anyone describe the symptoms of MAF failure?

I have been driving around in another car for a few days, but when I got back in my Scooby I am sure it's performing better than it used to, and I am just a bit afraid the MAF might be failing and therefore the engine running a bit leaner, hence the performance improvement.

I had a MAF failure before, but it caused very lumpy running, so it was dead easy to spot. Are there other symptoms as well?

Any advice appreciated (especially you John Banks!!!).

 

A MAF can slowly deteriorate and the car just runs a bit leaner and more advanced.

Worth checking with an AFR meter, Select Monitor or Delta Dash.

 

Thanks John.
Your swift and informative reply is much appreciated.
I'd better get it checked out.
Do you happen to know if it's possible to mail order a new one and fit it yourself, or does it require a specialist?
I was just thinking, since I know it will fail one day I could order one, swap it over, see if there is any difference and either leave it on, or keep it safe for when needed. Or do I need a more scientific test?

 

Oh dear, I had my car checked.
My suspected MAF failure turned out to be early signs of big end failure, which actually you can hear if you lift the bonnet and listen carefully.

I've left the car for a full rebuild by Graham Goode Racing, but it's going to cost about £5K for a 'proper job'.

The car has been running 348BHP since it was 12000 miles old though and it's done 78,000 miles, the last 30,000 of which have been pretty hard, so for a 5 year old car, that's not so bad.
They did say it would last long enough to part ex on some poor sod, but I haven't the heart to do that to a fellow enthusiast, on top of which what else can I get with the performance without a further 25-30K investment?

So I will be without it 4 weeks (I have a Civic Type-R as my second car though, so not so bad), and will get it back re-built by a highly reputable engine rebuilder, and a 12month guarantee on it.

 

what other checks did they do?, it could just be a bit of piston slap or a noisy tensioner/idler.

 

They haven't done any other checks yet.
They did call 4 engineers in to listen, each one nodded and grimaced :-(
I have had piston slap for 25K miles, and I know what that sounds like, but this was after the engine was warmed (after 22 mile run actually - although I had been running it off boost to avoid problems).
The reason it's expensive is I've asked them to do a proper job and use uprated bits when they put it back together, plus it's an STI4 engine, so it's quite expensive by default compared to a UK engine.

 

For such a large expenditure I would want independent confirmation before the money starts flowing.

Oil pressure should be abnormal??

 

Someone in the Wanted section was selling a good condition STI 4 engine a couple of days ago, this could be a cheaper option.

If it was my money though I would get my name down on the US 2.5 short engine group buy and reuse your STI 4 cylinder heads etc.

Colin.