[JeremyD]

Must I replace my MAF if the metal screen on the inlet side is broken?

 

[jsp]

If you have a good air filter and all the intake seals are good I wouldn't think so, been driving mine with about a third of the metal screen ripped away for about 60,000 kilometers.

 

[JeremyD]

My airfilter is 100% just wanted to make sure nothing would be damaged

 

[paul.adshead]

I've been driving without the screen at all for about 80,000km with no ill issues. An early backfire from the muppets that installed my LPG system broke it on mine.

JSP: I would NOT drive with part of the screen missing - either fix the screen or remove it. Even though it is fairly open weave, it WILL affect the air distribution pattern, downstream of the mesh. Immediately downstream of the mesh is the MAF sensor, which senses airflow via the central tube. If your mesh is partially missing, then more air will bypass the central sensing tube and the MAF reading will be incorrect. I would remove the mesh and run an adaptive-reset in the ECM (- I seem to remember you have a diagnostic computer?).

 

[JeremyD]

Thant makes sense didnt think of it like that will remove it asap. I dont have a diag PC shouldnt the ecu reset the air/fuel mixture itself?

 

[keithdixon]

It will over time. It learns over a period so will learn the clean settings from the MAF

 

[Dan_UK_1984]

I'd also be concerned that if bits start breaking off they may end up somewhere you don't want them!

 

[JeremyD]

True story! Will get rid of the screen asap! Did a little search about cleaning the maf is it advisable to remove the pop rivets and clean it properly or will squirting some contact cleaners into the maf do the same job?

 

[paul.adshead]

I just emptied some contact cleaner down the middle of mine. Drilling out rivets/re-sealing/etc sounds like it is deemed to fail or get really expensive. You'll be amazed at the colour of the rubbish that drains out of the sensor....

 

[JeremyD]

I was also a bit nervous to remove the rivets so only sprayed contact cleaner into it it cleaned up pretty nicely

 

[Peter Sanders]

Hi

Even though it is fairly open weave, it WILL affect the air distribution pattern, downstream of the mesh.

Initially I did not think this was too critical, keeping in mind how thin the screen is. However having replaced my MAF only last Friday I still have the faulty unit and decided to examine just how it is setup.

First of all, both the plastic "grill" in front of the mesh and the mesh itself are "keyed" this means that they must fit in a specific (rotational) position. This position looks to be at 45deg to the maf wire. So I therefore assume that the air distribution patten does have relevance. My thoughts are though, that the plastic grill is of more importance than the mesh as the plastic grill is much "thicker" than the mesh.

If your mesh is partially missing, then more air will bypass the central sensing tube and the MAF reading will be incorrect.

This is not logical. More air will not pass the sensor! The engine will STILL only draw in the amount of air it needs. The displacement of air or the distribution pattern may change slightly, but there will not be an increase in air mass.

How did the mesh break? If it is constantly disintegrating for some reason then yes, I would remove it. If it has been broken due to mishandling/accident and therefore not likely to break further then I would leave it alone.

I would remove the mesh and run an adaptive-reset in the ECM

From my limited, though recent venture into the realm of MAF sensors I would not recommend the adaptive reset. I chose to do this adaptive reset during my MAF foray and it made the already poorly running engine MUCH worse. It partly recovered after a few kilometres of driving, but due to the faulty MAF sensor, the values could not recover properly. Replacing the sensor IMMEDIATELY improved the engine operation and I did not have to do anything with the RCL (Rovacom Lite) to "adjust" the running conditions - it just adapted.

So if you remove the mesh or not, the engine will still run as it did prior to any "mesh fiddling" on your part (provided you don't break anything or do something silly )

 

[p38arover]

Mine blew out after an LPG backfire and I drove without it for another 6 years.

 

[jsp]

Hmmm I don't know what happened to mine, its been busted for a long time, I suspect it was heavily handed when the car was serviced by a shop, but its done over 60,000 k's with a mashed up mesh so I am not touching it, I can't afford a new MAF at the moment, if I fiddle it might break!

 

[keithdixon]

I bought a cheep maf off ebay just to get the mesh. popped it in and within a week had a backfire from the single point LPG system which blew it out.
Replaced the lpg system to multipoint and has now run for months without a screen.

 

[Keijo]

Peter,

I don’t think anyone actually said that there will be a change in the actual air mass, but that the reading of the actual air mass will be out of calibration because either more or less air will impact the actual sensor inlet because of the disturbed air flow.
The incorrect reading of course results in an incorrect amount of metered fuel injected.
I think you just misread it, so the statement is logical.
I would certainly remove any damaged mesh for all the reasons stated above.

Regarding drilling out the rivets, I just did mine last night and it was a very simple and safe operation. The only trick was to remove the entire assembly from the tube and not to try to just prise the electronic module off.

The sensor elements are not too fragile and were easy to clean with a spray can of electronic cleaner and then dry out with an air spray can. No touch though!
Both sprays available from electronic retailers such as Tandy or Jaycar for example.
Compressed air could be a bit savage and might contain contaminants so I would not recommend using that.
The small rivet studs remaining in the tube assembly must be removed to allow for the self tappers but they pull out easily with pliers.

Simple to re-insert and I used small black self tappers to tighten up the show and all went well and easy.
The key is to just take care and do the job slowly and methodically.

Truck now runs very smooth.