Mass Airflow Sensor -- 93 850glt

Post by **luketrash** » 07 Jan 2007, 14:18

I was just thinking to myself last night that I should clean my MAF. My car has a 'flat spot' on heavy accelleration. I can't tell if it's fuel injection related or transmission related.

So I went and pulled out the MAF element from its housing and got after it with some CRC contact cleaner I had sitting around. Brake cleaner would work here if you didn't have any contact cleaner, but this is kind of an important part...

Anyway, both my 98 Beetle and the Volvo 850 have these newer style MAF sensors that seemingly don't have the platinum wire stretched across a span of air. How do the new style ones like this work? I'm just curious, so I know what to concentrate on when cleaning them. In the case of my Beetle, they are notorious for failing way too soon, and used to cost 300 dollars to replace. The consensus after many years of investigating seems to be that dirt/dust fouls them and causes them to burn up internally. My older Volvos use to be fine for well over 100k miles at a time.

Mine in the 850 was thinly coated in motor oil. Apparently the excessive blowby at the crankcase is also backing up into airbox line enough to get oil on the MAF. I'm getting ready to go on a little drive, so I hope I notice a difference.

Post by **luketrash** » 07 Jan 2007, 19:37

Here's the followup: Amazingly, the dip in the power curve has nearly vanished. The car idles slightly smoother too. The power gain feels about like the step between a regular and K&N airfilter add-on, so that's good. I'm hoping it will all pay off in increased fuel economy.

The biggest difference today has been starting the car. It starts quicker and smoother.

So, it's simple.. Get your torx driver, pull out the MAF and clean it with electronic contact cleaner.

dejongmc · Post by **dejongmc** » 08 Jan 2007, 07:11

I just cleaned my MAF this weekend after reading this threat.

But I used alcohol (70%), put it in a bowl, put the sensor in there for a few minutes while keeping it moving around. All little black particles came of and today I noticed the car is more responsive to the gas paddle.

Post by **luketrash** » 08 Jan 2007, 07:26

Just a note: Alcohol can melt plastics and epoxies that are used in this sensor. The contact cleaner stuff dries extremely quickly. Less likely than if you used acetone (carb cleaner) like some have mentioned online.

But, it sounds good anyway that there was an improvement.

Another thing to add to the thread: When I drive my car hard, I get a potent smell of sulphur coming from the catalytic convertor. Last night the smell seemed almost nonexistent, which tells me that with the MAF dirty, the car must have a tendency to almost flood the vehicle with a rich mixture (that the catalytic convertor has to work overtime trying to clean as it blows out the exhaust) when you're running it near or at WOT.

I had my converter checked with an IR thermometer to check for blockages last month and the front and back both run at the same temperatures.

So perhaps this is another added benefit of keeping the MAF clean.

Ronniedasaint · Post by **Ronniedasaint** » 24 Mar 2007, 14:49

WOW! What a difference a cleaning makes.

I am not handy at all and this was super simple. I feel a tremendous difference in the ride and the idle now. My 94 850 Non Turbo 185K had been very spry when I first bought it at 165K but lately had seemed sluggish and my mpg suffered hovering between 17-18 after originally being around 22 mpg. But most of all it didn't feel like it used to. It's now idling much smoother/quieter and the pickup is what it used to be. I'll have to see what my mpg is looking like after this tank of gas.

Now I just have to figure out what's up with my seat recline motor!

Ronniedasaint · Post by **Ronniedasaint** » 26 Mar 2007, 13:51

The MAF sensor I cleaned this weekend is a replacement I had switched out during the summer. Anyway, I just wanted to share where I got mine because I know they're expensive:

Ebay seller: tomsforeignautoparts

He has a slew of parts and I think he gives a 6 month guarantee. I definitely think a salvaged MAF sensor is the way to go. Buy it, clean it, install it, clear the codes and go on with your badass self!

cc2times · Post by **cc2times** » 22 Sep 2009, 14:42

Newbie here.......after reading this thread I went and pulled the MAF. To the naked eye it seems clean but I don't have the cleaner around to test this. My question is, even though it LOOKS clean, could it still be dirty??? Starting the car I have to keep my foot on the gas for a while or it stallls. After about ten minutes of driving it idles normally again. A suggestions are greatly appreciated.

Coops

P.S. Shop told me its was the MAF asnd the TPS

Post by **Ozark Lee** » 22 Sep 2009, 16:12

The sensor element itself in the MAF sensor is incredibly sensitive. So the short answer to your question is yes, it can look clean and still be dirty. MAF cleaner is dirt cheap when compared to a whole new sensor so giving it a spray to see if things change is worth it in my opinion. If you do clean it just give it a spray and let it dry, don't scrub it or even touch it.

...Lee

beoutside · Post by **beoutside** » 30 Aug 2010, 14:43

watch out some electronic cleaners some may dry with a residue,
buy the specific MAF cleaner at your autoparts store AND LET COMPLETELY DRY before install, it may save you a headache later!

Paul-93-850 · Post by **Paul-93-850** » 10 Dec 2010, 18:24

I had similar problem on my 93 850 but the issue turned out to be an unseen hole in the underside of the nearby air hose.

I wonder if the CRC company simply labels their carburetor cleaner as MAF cleaner. Is there a really difference? A Volvo mechanic told me carb cleaner is OK.