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The mkiv Supra Owners Club

Cleaning the MAF


Alex

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I've decided that after a particularly dusty trip to LeMans I'd like to clean my MAF (and airfilter)...but how is the question?

 

I'm not talking about removing it, I know how to do that, but what liquid should I use?

 

I've thought of the following...

 

1. Petrol

2. Toluene

3. Acetone

4. Brake Cleaner (but I'll have to buy a bottle as i don't want to use a powerful aerosol on such a delicate part)

5. GUNK (engine cleaner)

 

Which would be best? The MAF is piece of plastic with a fragile hotwire inside.

Ian thinks petrol would/could bugger up the plastic so don't use that. My favourite I guess would be a cup of brake fluid. But if anyone's got a better solution I'm all ears??

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What benefit do you see in doing this ? (other than, it's clean)

 

If the filter is doing it's job right then, you should not have any dust, right ?

 

The risks involved £££ if it goes Pete Tong ?

 

It's not normally a servicable/clean up item.

 

Just interested :)

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I've read that a dirty one can cause overrun/over fueling on liftoff...

 

With an atmospheric BOV on the car too this would be really bad..watching my AFR's I'm not happy with how slow the system is to react to a lift off.

 

I've read on a few sites the MAF's voltages get screwed up by dirt and that they lose resolution and can knacker the autobox shifting (not a problem I should worry about) but with 77,777+ miles on the clock...surely even with a decent filter there will come a time when it's not clean enough?

 

I realise that yes I could bugger it up, but if Chris has a backup I can purchase off him then I already feel more comfortable about trying to clean mine.

 

But I can stress enough that I would like to do this as safely as possible.

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Sorry for the question but what does the MAF do? :shrug:

What gains do you get?

 

:stupid:

It measures the air going into the engine on VVTi Supras. Its a replacement for the speed / density air metering system used on non VVTi cars. Its part of the stock system, so there are no "gains". Alex thinks his might have got dirty at LeMans, and wants to clean it.

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Sorry for the question but what does the MAF do? :shrug:

What gains do you get?

 

:stupid:

 

Mass Air Flow (meter)

It's a stock sensor on the UK and VVTi spec Supra's.

Your J-spec runs a MAP sensor.

 

It's not a performance mod.

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I've read that a dirty one can cause overrun/over fueling on liftoff...

 

With an atmospheric BOV on the car too this would be really bad..watching my AFR's I'm not happy with how slow the system is to react to a lift off.

 

I've read on a few sites the MAF's voltages get screwed up by dirt and that they lose resolution and can knacker the autobox shifting (not a problem I should worry about) but with 77,777+ miles on the clock...surely even with a decent filter there will come a time when it's not clean enough?

 

I realise that yes I could bugger it up, but if Chris has a backup I can purchase off him then I already feel more comfortable about trying to clean mine.

 

But I can stress enough that I would like to do this as safely as possible.

 

 

Got it sitting on the kitchen table mate.. Its only seen 36K :respekt:

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It measures the air going into the engine on VVTi Supras. Its a replacement for the speed / density air metering system used on non VVTi cars. Its part of the stock system, so there are no "gains". Alex thinks his might have got dirty at LeMans, and wants to clean it.

 

Dude, can you have a word with any err local aquaintences within say a 1mile radius ;)

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I was always led to believe that if you were going to do anything with it, it is to change it. Not the most cost effective way, but surely the safest.

 

When I had my scoob, I changed mine at a cost of £250 but it sorted any issues out that the car had

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Great stuff there Digsy, but are you saying it's ok to clean it or are you saying look at these bright shiny MAF's, buy a new one!

I guess what I'm saying is that if you want to clean it then the data in those documents might give you some pointers as to what is and is not safe to use. Conversely, you could also read the data as saying that they are pretty well protected against dust.

 

TBH if it is working then I'd leave it be (unless you know that its full of dust, in which case you have more to worry about that the MAF meter! ;)

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I have successfully cleaned my MAF with electrosol (electrical contact cleaner) after it became contaminated with K&N filter oil. Three years later still works perfect. Make sure any product you use is guaranteed pure and will not to leave any residual evaporative deposits.

 

The mass air flow sensor works on the simple "hot wire" principle. A constant voltage is applied to the heated film or heated wire positioned in the air stream or in an air flow sampling channel and is heated by the electrical current that the voltage produces. As air flows across it, it cools downcausing resistance to drop as the sensor temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is proportional to the mass of air being pulled into the engine. The engine management system meters in the proper amount of fuel to maintain proper stoichiometric A/F ratio. Technically this is 14.6 to 1 for petrol but in practice the Supra will and should run richer(~12:1). MAF's are simple, reliable and fast reacting but sit in the air flow so can be restrictive and rob power.

 

derek

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