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Discussion Starter #1
Hi!

I cleaned my MAF today (thanks to Vigge for the advise) using isopropanol spray. The result was very surprising (at least to me):

While my car was pushing a steady 1.3 bar from 3200 to 4500 rpm, with occasional spikes to 1.4 bar, after cleaning the MAF, the car now boosts steadily with 1.4 bar and spikes to 1.5 (!). At 4500 rpm, this will translate to quite a few hp! (probably more than the aircon )

I did a little research, and this is what convinced me:

"Since this unit is not cleaned by an automatic process or during routine servicing, it is inevitable that over the years the MAF will become gradually dirtier and this will cause it to read more air passing into the engine than is really happening, and the fancy automatic computer control metering the fuel and everything will be misled and will obviously pump more fuel into the engine than is actually needed. Conclusion, clean your MAF regularly because it will become inaccurate and it won't be cleaned by anyone else, and the effects of a major engine sensor giving readings that are up to 30% or more higher than they should can obviously be quite extreme"

Just wanted to share this with you.

Yours,

Philip
 

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That's a very interesting theory about the MAF sensor. But on the C900's at least, I know that every time you turn off the car, if you look at the MAF sensor 4 seconds after shut down it will glow white hot for about two seconds. This is supposed to clean it off every time you drive the car. If you're seeing more hp as a result of cleaning it, perhaps that somehow does not clean off everything on it. But that's a platinum wire, and it gets hot enough to melt steel off it, so I can't imagine what could stay on to clog it up. I dunno what's going on.
 

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Possible. Very possible. And carbon sublimes at a higher temp than platinum melts. Just seems like heat shock would break off most of it. ButI can see why cleaning it could help. Also, I would think a coated MAF sensor would make the engine run lean, not rich. As the sensor detects air by how much it is cooled by the intake charge, and a coating of carbon would insulate the platinum wire, thus causing it not to sense some of the intake air because it would not be cooled as much. This would make sense with a loss in boost except that ... I believe on the Viggen, as in most turbo cars ... at WOT the engine is run on a factory map and does not use the airflow sensor or O2 sensor. Rather just the MAP sensor, temp sensor, and Ionization Gap sensor. The MAF sensor, and O2 sensor, are just for highway cruising in most cars. I could be wrong. Someone should ask the guys at MapTun about that to see if it makes sense to them. My new Saab probably isn't old enough to have this problem, but my C900 is running lean and just failed a smog check as a result, so perhaps this could benefit it!
 

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Discussion Starter #5
Well, there was quite some black stuff dripping from the MAF when I sprayed it with isopropanol...

Yours,

Philip

BTW I think only Trioic 7 uses a MAF, the older models use a MAP ?!?
 

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Phillip you weren't using an Oiled filter like a K&N were you? They're known to coat MAF sensors with carbon as the oil burns off the 2000 degree wire. Could be related? Oil filters filter better than peper ones for the most part, so perhaps it's worth it to clean your MAF once in a while, for the added flow and filtering.
 

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Discussion Starter #7
Adrian, in fact I´m using a JR air filter, which is oiled - as most people in this forum do.

Yours,

Philip
 

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Originally posted by philip hs:
[qb]Adrian, in fact I´m using a JR air filter, which is oiled - as most people in this forum do.

Yours,

Philip [/qb][/b]
But not Bill with his monster gearbox eating Aero...

Obviously trying to keep his torque out of the gearbox death zone.

Andrew
 

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Hello you all,

If the MAF unit is dirty it will first have an affect under WOT conditions. While cruising o2-sensor will make sure that the car is not running lean, even if MAF cant measure properly.

Lambda is not read under WOT, so in this case I belive the system cant correct the MAF reading.
When the unit is dirty more air will pass through the it than the reading is showing.
The T7 will fuel the car some what based on MAF reading, and the result will not be correct. Under time timing will also be altered due to incorrect MAF value. The car wont tell you this with CEL until T7 runs out of compensation margin. By then the thing are horribly wrong.
This leads to lack of power and the engine will also run lean.

So what causes this?
The my knowledge there are to reasons, the filter will let fine dust through and it will coat the MAF's platinum plates. Second possible cause is the oil used on surface of the filter.
Oil is eavan more harmful because it will cause the unit to burn. I know some people are kean to used motoroil based product to oil the filter. These types of oils will penetrate the filter and travel on to MAF. It has been saind that oil products made for this purpose will not carry on to MAF, but I think it will do just the same if used in to big ammounts.

In my case I went back to the original filter, when I realised the optiflow cone did not do the job. I cleaned my MAF twice under 6 months. Both times there was fine bild up on the unit. After cleaning the affect on performance was noticeble. I only used proper product for cone cleaning and oiling, but it did not work for me.

I have decided that the original filter is good enoung for me. Some test show that a free flow filter will only have about 0,2% less friction.
I do not think it is woth to play this MAF game when the outcome is not that great. A new MAF will cost about 250Eur.

Folks, when cleaning MAF only pure isopropanol cleaning sprays should be used. Many cleaners contain coating like substances. The compaunds will only harm the unit.
 

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Hi.

Sorry for intruding, but can any give me a hint to where the MAF is (eg. the sensor next to the airfilter box?) and where I can get the isopropanol spray from (eg. Halfords!?).

Ta.
 

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Originally posted by jimmyjims:
[qb]Hi.

Sorry for intruding, but can any give me a hint to where the MAF is (eg. the sensor next to the airfilter box?) and where I can get the isopropanol spray from (eg. Halfords!?).

Ta. [/qb][/b]


The MAF is colored red on the picture.

Pure isopropanol sprays should be found at any store where electronic components are sold.

There are few things to rember if you plan to clean your MAF.

1. Do not touch the platinum plates, you will destroy the unit. So only spray it but dont touch it.
2. Make sure all of isopropanol is evaporated before you start the car. A hair drier is a good tool, blow some air through the unit.
3. Reset your ECU, this is done by disconnectin a battery cable for 15 min.
4. re-calibrate your car.
 

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The filter I have on my Viggen is a non-oiled cone filter. Doesn't seem to add much power, but the milage went WAY up. It payed for itself literally in two weeks just on gas savings so it must flow at least slightly better than the stocker.

Also about what Vigge said. I think that makes some sense. I can see the MAF sensor being used in conjuction with the MAP sensor during WOT. It might not be a bad idea to clean your MAF sensor regardless of having a oiled filter. No filter can possibly filter out everything. Seems like a good idea just to clean it off every now and again anyway.
 

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Discussion Starter #14
Originally posted by Playsuit:
[qb]Now everybody starts to clean MAF and there will be huge sales increse of spareparts/new MAF's      [/qb][/b]
Did I forget to mention that I work in the MAF industry ?
 

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Vigge,
In your post you said to "re-calibrate the car" after cleaning the MAF. Is this something the car does automatically? If not, can you elaborate more please?
Thanks!
 

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Yes you have to do that with all steg's.

Accelerate four times on gear 4, rpms from 2000 to 4500 with full gas and you car is set.
 

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How does this apply to an auto trans? Does this need to be done on a rolling road? 4500rpm in 4th would put me close to maybe...130mph? (200+kph?)
 

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Hmm I really don't know how is it done with automatic. My aero is manual and speed was between 60-170km/h. I'll try to browse some answer to you.
 
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