The usual test method is to fit a new one and see if it fixes the fault.

Usually MAFs are next to no good long before they deteriorate far enough to produce an error.

 

try giving it a clean first before outlaying some dosh...

Remove the MAF - undo the metal clips with a pair of small pliers or lever off with small screwdriver, undo the cable tie which keeps the connector cable tidy to the air duct.and then the connector remove the MAF.

There are 2 TX secrurits screws that clamps the sensor to the MAF body...these can be undone with pliers as they are not to tight.

Pull the sensor head out and stick the MAF body a bowl of luke warm water and slosh about...use a sponge to clean the inside of the MAF body but do not touch the Mesh. then put back in the bowl and leave for about 20 Mins...

To clean the sensor head you need anti-static cleaner from Maplin or any radio hobby store..

Spray liberally all over the head......

You will see a channel in the sensor head, and will notice a wire running inside....you can clean this with a cotton swab with cleaner applied.....don't go to mad just apply gentle pressure.

At the side of the sensor is a metal plate within another channel...you can clean this using the cleaner and some tissue, wedge it in the grove and slide in and out....you can use a small screwdriver to exert more pressure to clean the plate and the edges.

The sensor heads..electonics is sealed so don’t worry too much...but still be careful.

When this is done....rinse the sensor head under luke warm running water from the tap and just cover the top part of the head where you have cleaned...

when done remove the MAF body that was soaking, test the mesh for cleanness with a cotton swab, if still dirty use the anti-static cleaner to clean more..and re wash in luke warm water.

Lay both the sensor and the MAF body...on a tea towel on a radiator to dry ...

Re-Fit the MAF all back together and put back on the car.

 

The only way to test a MAF would be to take it out and test it on a flow rig.

However you should be able to get a good idea if you get the MAf output at idle and at full throttle and compare the figures with a good MAF.

 

Thats a pretty thorough description of how to clean it!!
I've already given it a bath in Isopropanol but to be honest it was already as clean as it could be!
Is there a way of testing it electronically? And why would it suddenly just give up after the engine was rebuilt?

 

These may help:

 

Many thanks David. I'll get out my multimeter first thing in the morning!!

 

If you are cleaning the MAF an empty 50ml Nescafe coffee jar is exactly the right size for the MAF so you don't waste your expensive cleaning solution.

 

David, any chance of similar screen captures for the 147 1.6 TS 120bhp?

 

David, any chance of similar screen captures for the 147 1.6 TS 120bhp?

Some of the info is missing in my version, your engine is one of them!

 

Murphys law. N'eh mind David, thanks anyway.

Are the figures likely to be miles out, where is the actual plug the readings are taken from?

 

The plug is the connection on the MAF sensor.

 

with diagnostic computer connected, if you rev up from idle the values read by the AFM should go up also. if it's working with a delay, it's on it's way out

 

The voltage on mine goes up with the revs.

 

I've ordered one from the local Motor Factors. £40+vat and sale or return!
If it hasn't cured it, I'll take it back and get a refund!!

 

£40 for a MAF seems too cheap...are you sure it was one for your engine?

Did Alfadiag tell you what fault codes were raised?

 

Next!!
The new MAF has made no difference!

 

Did the errors reset?

 

They reset but as soon as the engine was running the error came back. Even when I reset it with the engine running, the lamp goes out and then comes straight back on. Suggestions??
There was a mention on a website that there are other things thatcause the MAF to show an error. The TPS was one of the things IIRC.

 

If a new Maf doesn't fix it the Lambda is the next likely culprit.

The usual way to test the maf is to unplug it and see if the car runs better. the reason being the ECU will go into default (emergency) mode. If the car runs better on default mode than with the MAF connected then it is stuffed.

 

I have discovered that lambda sensors don't like anti-freeze and there is every chance that a bit of coolant got in the downpipes when I did the cylinder head work. New one on its way!!

 

I have fitted the new MAF even though when I tested it as previously suggested, it seemed OK (it's hard to check the voltage at 3k rpm when its hunting up and down!). The fault was still there.
I have fitted a new Lambda sensor and there is still no improvement and the fault light still comes on as soon as the engine is started after it's been reset, or as soon as it's reset with the engine running.

This car is seriously dampening my lifelong desire for Alfas!!!

The car does seem to run a little better but the jerkyness is still there when the Selespeed is doing its thing. I'm considering changing the fluid to see if that makes any difference.
Any other suggestions would be welcomed!!

 

I'll fire up the laptop to get what the exact fault codes were.
The MAF is a UK produced (or boxed at least) item from a reputable Auto Electric supplier. I got it at trade price. The lambda was also at trade for £40.

 

The MAF is a UK produced (or boxed at least) item from a reputable Auto Electric supplier.

Not a genuine Bosch one then.

 

No but the geniune Bosch one I took off was OK!! I have since tried it in another car and it works fine. I have also tried the new 'pattern' item and it works OK.

 

The AlfaDiag is telling me:

Failed Component Code: Air Flow Meter
Fault Symptom: Below Minimum Limit
Warning Lamp Status: Warning Lamp Illuminated
Fault Test State: test not cpmplete for this error
Fault Code Storage State: Error present at time of request
Event Count: 64 count
Filter Count: 0 count

And then a load of engine speed/emvironmental stuff.
Any suggestions folks???

 

I think that is telling you that the AFM is stuffed. And basically that error has been recorded 64 times. The enviromental stuff will be alll over the place if the Maf has failed, though I am sure someone will correct me if I am wrong.

Simon.

 

It does seem odd that before tha cambelt bust all was OK and then after it has been fixed, the ECU warning lamp has come on and allthis trouble. It's also odd that two MAFs are faulty!!