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Registered
1999 STB Automatic
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1,558 Posts
Discussion Starter · #1 ·
Had the pleasure of a visit from JGM earlier this week. However all wasn't great as having tested the MAF he indicated that it needed to be replaced, so that was it. :shrug:

As he doesn't carry spare ones anymore i had to order one (genuine) from ICP.

Good news though is that i fitted today and it feels like the car has been remapped, hence proving that the old MAF was ineffective.

Trouble is, unless you are wise to these things, or your lucky enough to have JGM or someone equivalent run a test, you might never know your MAF needs replacing as the decline can be insidious to the point that you don't really notice it. I wonder how many of us are driving around with a MAF that is either kaput or on its way out?

Interestingly JGM suggested buying 2 MAFs and switching them each service. I hadn't come across this advice before.
 

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Registered
1999 STB Automatic
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1,558 Posts
Discussion Starter · #3 ·
Yep. I wasn't watching, but it involved the use of a laptop. :confused:
 

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Registered
2000 Forester S Turbo manual
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1,670 Posts
I'm awaiting a replacement MAF at the moment
My idle would fluctuate and more recently stall as the idle
Would fall to low, I took a lend off bass makers MAF
For a few days and the difference was chalk and cheese
Drives like a new motor, so definitely worth looking in to.
 

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01 UK S-Turbo AT
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1,556 Posts
Would a faulty MAF not throw a CEL?

It's an interesting thought. If I blip the throttle on cold start-up the revs drop by about 50% and stay there. Not sure if this is new or old 'idiosyncrasy'...

Cheers

Mike


Sent from AutoGuide.com App
 

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Registered
1999 STB Automatic
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1,558 Posts
Discussion Starter · #7 ·
Be easy if it did. Hence why you can be running the car for several months or longer without realising, unless you are wise to the issue or have the electronics to test for it. But the impression i had from Simon is that most 'normal' mechanics wouldn't pick up something like this.

Still curious about getting a second new one and switching it at service time. I suppose at least this way you would know at least annually (or sooner depending on service schedule) whether one of the MAFs has gone.
 

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Smooshed FOTY 2011
2005 Lifted 2.5 XT 5-Speed MT Dual-Range
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5,732 Posts
A bad MAF doesn't usually throw a CEL. You can get misfires, hesitation, choppy power delivery, rough idles, and even pinging that can cause boost cuts that will put the BCS into fail safe mode. All this happened with mine. Thought it was a major issue. Swapped the MAF with a known good one, and bam, perfect. No more issues. They fail around 120-150k miles according to my local Subaru master tech.
 

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Registered
2008 GRB 20th anniversary 6 MT
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6,575 Posts
How many miles did the old one have?

They used to be "consumables" on classics around the 75k mark.
 

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Registered
1999 STB Automatic
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1,558 Posts
Discussion Starter · #10 ·
spooky....mine has 75k.

Although there was a code on the old one 1702, which i assume might be a date code, so possibly < 75k miles.
 

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Lucas
2004 Forester XT Manual
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2,825 Posts
Had the pleasure of a visit from JGM earlier this week. However all wasn't great as having tested the MAF he indicated that it needed to be replaced, so that was it. :shrug:

As he doesn't carry spare ones anymore i had to order one (genuine) from ICP.

Good news though is that i fitted today and it feels like the car has been remapped, hence proving that the old MAF was ineffective.

Trouble is, unless you are wise to these things, or your lucky enough to have JGM or someone equivalent run a test, you might never know your MAF needs replacing as the decline can be insidious to the point that you don't really notice it. I wonder how many of us are driving around with a MAF that is either kaput or on its way out?

Interestingly JGM suggested buying 2 MAFs and switching them each service. I hadn't come across this advice before.
Ha! Very interesting. What were the symptoms in your case? Or was it pure curiosity which push you to check it?
 

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Registered
2009 Forester Xt LTD 4EAT
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44 Posts
I just got my car back from the dealer. They changed out my MAF under my extended warranty. No CEL. It was hesitating after 3k RPMs. They originally thought it was turbo failure. They reflashed my ECU and replaced the sensor.

50k on my XT.
 

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Registered
1999 STB Automatic
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1,558 Posts
Discussion Starter · #14 ·
Ha! Very interesting. What were the symptoms in your case? Or was it pure curiosity which push you to check it?
Simon Roe (aka JGM) checked it as it was due to be ECUtek'd. Says he always tests them as step 1 nowadays otherwise the benefit of the ECUtek is compromised and ultimately will harm the engine.

Looking back at the difference, previously the car ran a little rougher on idle and needed to be driven harder to get decent acceleration out of it. But it was only noticeable to me having driven the car with the new MAF installed, as i had got used to how it was driving previously.
 
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