Have been reading Colin's excellent guide to Cleaning the MAF Sensor in the excellent Lexus Knowledgebase.

I am gonna have a go at this

Have some questions;

1 - what is throttle body cleaner or 99% pure isopropyl alcohol, and where would I buy it? Roughly how much should it cost?

2 - How do I tell if the sensor wires are dry? What happens if I put it back in and there not completely dry?

I'd be interested in knowing this too. Recently my fuel consumption has worsened and I want to see if this helps resolve it.

I would use isopropyl alchohol. Normally found in electronic stores. I use AF Isoclene which you can get from here:
http://www.consumables.co.uk/product_info....ducts_id=300054

also RS sell it (part # 101-5766 http://rswww.com ) and their own product. May be able to get some in Maplin as well.

Should cost about £5

To make sure it's dry just turn up side down and shake, the excess will come out and then leave for a minute or two. The alcohol evaporates very quickly so even if there is some still in there by the time you re-installed the sensor it would be gone.

Thanks Col - just ordered it from consumables.co.uk


Claire - let me do mine, and then I'll send you the bottle so you can do yours?

Assuming one bottle will do two cars.

One bottle will do about 100 cars however I don't have a procedure for the 300. Not sure what type of MAF sensor it uses, it's different from the 4.3 one and I don't have access to a 300 to look.

ok - maybe I won't send it to Claire then

you never tried on your 300 mate?

No never got around to it before I sold it.

If I get access to an IS300/GS300 then I can have a look.

Where are you based Colin - you can always take a gander at mine.

I'm not too far from you Claire, Woking

PM with when you're free and perhaps we can arrange to meet up? Would be our own mini-meet!!

Colin,
I live in Woking and I own a Aristo TT that is probably due for a clean, maybe you could show me and take some piccies???

Ta
Tom

The TT engine doesn't use a hot-wire type of MAF sensor so this type of cleaning is not needed.

What sort does it use? Any info greatfully received.

I wouldnt recomend it with a hot wire MAF, sorry to disagree but we used to get this all the time with the Skylines as well.

The whole point of the hot wire type of AFM is that the sensor wire is heated to burn off the oxidsation and contaminants that collect on it.

If the AFM was getting to a point that it was prone to contamination we generally found that the AFM was begining to lose resoloution anyway and would be best replaced.

Fair enough on the N/A Lex the problem would not be as potentially damaging as it would be on the Skyline but the point still remains. If the AFM is losing resolution the vehicle will be running progressively leaner as the air volume increases and this will have a detrimental effect on fuel consumption.

At the end of the day thats only my opinion based on the tests we ran on the Nissan AFMs which do run very close tolerances so by all means give it a bash, it certainly wont be damaging unless the sensor is in a very poor condition anyway.

Just be aware that its not a "miracle cure" you may well just be masking over a more significant fault.

The Aristo runs a MAP sensor (manifold absolute pressure) basically it detects vacuum and pressure in the plenum and adds fuel accordingly.

An AFM, MAS, (Air Flow Meter, Mass Air Flow Sensor) measures the volume of air passing through it and into the plenum and adds fuel accordingly.

Both have their own particular benifits and down sides.

I didnt mean that to sound like a lecture Colin, far from it, I have read your helpfull guide and am very impressed by it

I don't agree with that. The wire is heated so the other wire (thermistor) can measure the temperature drop which changes with the amount of air flow. When the sensor is new both wires are nice a clean and when you look at one that has been in use for a while the wires are black. If you monitor the sensor output before and after cleaning there is a slight difference which shows the dirt was having an effect.

You are correct it isn't a miracle cure but as the vehicle gets older it's mpg and performance reduce every so slowly and this goes some way to correct that.

When I cleaned the sensor on my GS430 with only 26,000 miles on the clock I instantly felt better throttle response and my mpg went up from 26 to 28.

On my RX300 with 76,000 miles on the clock I didn't feel any difference but saw a 1.5-2mpg increase on a common run.

I've also known poeple to have positive results on MR2s as well. Maybe the Skyline uses a slightly different system to Toyota?

It probably has a MAP sensor rather than a MAF sensor. The JDM Supra TT has a MAP sensor so I guess the Aristo does as well.

The Euro and US spec Supra TT has many uprated parts over the JDM version and that uses a MAF sensor

My 300 is close to 66K, I will plug the scanner in and data stream the sensor then do a before and after test and see if there are any voltage changes.

Actually, I will do a run with wideband on and log it then do the same with the AFM cleaned and see how it works out.

If you are seeing the results as you say then its got to be worth a try

I will post up the results towards the end of next week as I am moving building this week but as soon as I get a chance I will give it a try.

that would be excellent CrailLoser

I intended on reporting my mpg before and after anyway, I'll post my mpg and average speed before I clean it, then post the averages in a week or so.


I know my figures are 17.6mpg with an average speed of 21mph right now

bloody stop start daytime traffic. Will get better when I start hitting the motorways again

just updated the procedure slighty and added one for the RX300 in the knowledgebase.

nice one Col