Afms How Many Times Do They Need Cleaning?

[TommyR34]

Hi guys,

Took my car to GT Auto garage and got my AFMs cleaned twice within 5000kms, Is that over kill? Do they really need to be cleaned every 5000kms?

Thanks

Tom

[Moodles2]

They are self cleaning, when the engine is shut off the sensor wire burns hot to get rid of oil and crap that has accumulated on it. Not a good idea to excessively clean them manually.

[mad082]

did you ask them to do it, or did they just do it for you and charged you for it? if the latter, might just be their way to get a few extra dollars out of you.

also, what filters are you running? if it's an oiled air filter then there might be too much oil in it and it's making them a bit oily.

[TommyR34]

I monitored the voltage from my AFMs they show around 900mv then drop to 500mv to 400mv while driving causing the car to stop suddenly before coming back to 900mv which is not at an optimal running level, but I am still able to drive the car around, The mechanics either did not check the millivoltage on my AFMs or did not clean them as I wanted in my original first visit to their garage, I did not want my AFMs to be cleaned a second time as I had to diagnose the problem my self and from the long list of things I have already replaced (Turbos, Fuel pump, Injectors, Coil packs, new air filters, Spark plugs) it wasn't hard (even for a amateur like myself) to link the symptoms (stalling, hesitating acceleration) to the AFMs and recognize they need to be replaced.

To have them cleaned a second time in such a short space of time when I said I was replacing them with brand new nismo units is not acceptable as I never asked for them to be cleaned “again” they just did it and then rang me to say they've cleaned my afms again and said theres no problem with the car....So if I didn't know any better I would believe/trust them drive away and later find out and be baffled when the car starts stalling and hesitating again....Thankfully I am an experienced mechanic..Not

[TommyR34]

Got some more info on AFMs,

damaged AFM may lead to increased fuel consumption and increased pollutant emissions as well as decreased power and throttle response (I was only getting 250km to a tank)

The engine may fail to ignite, causing misfire and a large increase in unburned hydrocarbon HC emissions

Lean mixtures burn hotter and may cause rough idle, Hard starting and stalling, And can damage the catalytic convertor (I had some of my cat come out while I was on lakeside raceway)

or burn valves in the engine

The risk of spark knock/engine knocking (detonation) is also increased when engine is under load

Forced induction engines can be catastrophically damaged by burning too lean for too long

The leaner the air/fuel mixture, the higher the combustion temperature is inside the cylinder

Too high a temperature will destroy an engine- melting pistons and valves

So if anyone is experiencing any or all of these things its your AFMs, I have also been told that if your AFMs need cleaning then they are already on their way out and should be replaced. Cleaning might might make it run better for a while but its going to play up again sooner or later. Its much safer just to replace it, a faulty AFM will destroy an engine quick smart

Edited August 18, 2011 by TommyR34

[wolverine]

So if anyone is experiencing any or all of these things its your AFMs, I have also been told that if your AFMs need cleaning then they are already on their way out and should be replaced. Cleaning might might make it run better for a while but its going to play up again sooner or later. Its much safer just to replace it, a faulty AFM will destroy an engine quick smart

Whooah, slow down there.

Spraying the element with contact cleaner is hardly going to damage the element. If you are using an oiled filter that is over oiled then cleaning regularly is pretty simple insurance. If you are having ongoing issues with your AFM the most common reason is poor connections where they are soldered.

If you take the lid off the AFM and re-solder the connections (which is a 30-60 minute job for a noob) you can sort out the vast majority of AFM probs for not much effort. Certainly cheaper than spending $80-100 for a second hand one potentially with the same issues or >$300 on a new one.

[BOOZTJUNKEY]

This may explain the random detonation I have been having in the top of third

Hmmmmmm good info I'll see I'f it's my Afm and let u know

[TommyR34]

Kool

[R31Nismoid]

if you have varying AFM voltage, after you cleaned it.

It's just a simple case of the AFM is fked. Pretty common problem what you describe, and no amount of cleaning it will fix it.

[BOOZTJUNKEY]

Yeah I cleaned and it is still the same how are u checking voltage?

That is my next port of call according to consult it's not throwing errors so hmmmmmm

[TommyR34]

I used a Power FC hand controller to monitor the airflow mv, let it idle for about 5minutes, went from 1200 1100mv when I first start the car, then after 5minutes dropped to 900mv and then was randomly dropping down to 500mv 400mv mark at which point almost stalling, Really does help to do research

[BOOZTJUNKEY]

I'll have a look on consult and see I'f I can see Afm meter volts and have a look what's going on with it it's Been a while since I hooked up consult anyways :-)

[Nanogrip]

I clean (or try to clean) every oil change. Not over kill I think. There are sprays that are specifically made for AFMs out there, just a few dollars and you won't be finishing the can in a long hwhile.

[R31Nismoid]

The AFM has a voltage reading, can be seen by the PowerFC hand controller and no doubt Consult.

It's not the airflow reading you need to go off either.

It's the actual voltage. If it's stalling then the sensor for the AFM1 or AFM2 will actually show up as having failed.

I never clean my AFMs regularly. Once a year tops. Just use some degreaser and then heaps of water to wash it out.

Works fine.