m20 afm pre facelift v facelift

[magpie]

are there any differences between the afm's ?

i have two here with different numbers on them , they both have 4 pins but looking at my facelift loom [E reg] there are 4 slots but only 3 pins have wires off them and the 4th pin slot is blank .

the thing is i've just sold an AFM that was fully working on a black 325i facelift i have here and the buyer has said it doesn't work on his 325i which has left me with a dilemma .


any help is appreciated , Mick .

[Brianmoooore]

ETK doesn't show any production dated changes in a 325 AFM for the whole period they were made, although three versions are listed. That doesn't necessarily mean they are all interchangeable though - just that the latest version can replace the earlier, discontinued version.
A moving flap air flow meter has to have three terminals - each end of the potentiometer, plus the wiper contact.
The fourth terminal in an E30 AFM is for the inlet air temperature NTC resistor, which shares a common connection with one of the potentiometer pins.
AFAIK, all E30s have an IAT built into the air meter, and therefore have a fully wired four pin plug.

Does your customer really mean that it doesn't work on his car, or does he mean that replacing one AFM with another AFM didn't cure whatever problem he has, simply because the fault hasn't been diagnosed correctly?

[svenga]

It is my AFM in question..

Firstly, before anybody reads incorrectly, I am NOT claiming Mick sold me a faulty item until we determine what is what with these units.

My AFM has four wired pins, slot five is blank and has no contact. My loom has four slots, number five being again blank. The AFM I received of Mick has 5 pins on the AFM (I am unsure if number five is wired, I will not open the cover incase).

But the weird part is on the loom plug/s at his end, there are only three wired slots and the fourth blank?

The car is running OK on my current AFM. However when the new one was fitted it started fine, but idled extremely low and lumpy and stalled after around 30 seconds. I double checked everything and repeated the process with no luck.

Again, new blue temp sensor, new leads and plugs, ICV & TPS cleaned and checked with multimeter, all vacuum points resealed (new throttle gasket too). The AFM was the next port of call, but was pointing in that direction as when the unit was unplugged it made no difference until given a clean with contact cleaner. But this only solves the problem temporarily.

I will provide pictures later once I get home

[pianist]

Does your customer really mean that it doesn't work on his car, or does he mean that replacing one AFM with another AFM didn't cure whatever problem he has, simply because the fault hasn't been diagnosed correctly?

My thoughts exactly, the problem might be completely somewhere else

[svenga]

Does your customer really mean that it doesn't work on his car, or does he mean that replacing one AFM with another AFM didn't cure whatever problem he has, simply because the fault hasn't been diagnosed correctly?

My thoughts exactly, the problem might be completely somewhere else

But the car still ran OK (not brilliant) on my AFM which has a different loom & pin set-up.. Opposed to only just turning over with the new AFM fitted.

If the new AFM was the same as the one fitted to my car, working, surely it would behave exactly the same.

[pianist]

The car is running OK on my current AFM. However when the new one was fitted it started fine, but idled extremely low and lumpy and stalled after around 30 seconds. I double checked everything and repeated the process with no luck.

What was the reason you changed your AFM if car was running ok on it? I just can't see description of problem you had with your car prior to fitting "new" AFM

[pianist]

Surely if pins and loom are different on the new afm it must be wrong for your car

[svenga]

The car does not idle 100%, slight engine shake, slightly hesitant when just touching the throttle.

It has improved vastly through from where it was originally, but is still not right. AFM was the next item to change which would erase the intake side of things, but as said above after a clean it improved but the effect is temporary. Pointing that the AFM could be unhappy (I looked into repairing my own, but thought it would be safer to just replace with like for like).

Although everybody slated me for it, the Diagnostic test read an error code for the AFM too.

[pianist]

Did you check the plug under the inlet mani? I think its for connecting injector loom and it's known for rusting.

Also check your earth to engine straps

[svenga]

Earth straps are fine and the injector loom C191 plug has been cleaned with a brush and electrical cleaner.

Although it will be getting replaced for peace of mind once this aspect is sorted.

Pictures of both AFM's to come tonight, hopefully Mick is going to check out another unit at the yard too which might be identical to mine.

[HairyScreech]

Pretty sure all versions of M1.1 and M1.3 had 5 pin AFM plugs with 4 wires. The ETK diagrams seem to agree with this as well.

Are you sure there are only 3 pins on your plug?

What is the part number of the MAF, as the 320 mafs look identical but do not have quite the same resistance values.

[Brianmoooore]

Earth straps are fine and the injector loom C191 plug has been cleaned with a brush and electrical cleaner.

It's not the pins and buckets of the plug and socket that are the problem with these, although in severe cases they will be affected as well.
The problem is with wires rotting inside the rubber boot of the lower half. Water gets in, is trapped, and electrolytic corrosion takes place as a result of the ignition switched live to the injectors being present, as well as 'earthy' pins, such as the temp. sensors.
Similar thing to what happens in the driver's door A pillar plug and socket.

[Brianmoooore]

Pretty sure all versions of M1.1 and M1.3 had 5 pin AFM plugs with 4 wires. The ETK diagrams seem to agree with this as well.

An AFM + IAT needs four wires connected.

The signal from the AFM isn't used at idle (although the IAT is), although I think that an incorrect signal from the AFM when the engine is idling can cause problems.

[magpie]

i may have miscounted pins ... if svenga can get part numbers for his and the one i sold him and pics of the pins posted up i'm sure that might help

[svenga]

As requested, further information and pictures!

My current AFM: 0280202082 12866159

Slightly smaller black cap/lid, Idle screw in the top of alloy housing, perfect fit onto the airbox with the alignment studs. Serial number on the black lid.

New AFM: 0280202202

Larger black plastic cap/lid, idle screw on the side of the black plastic housing, lots more play when attaching to the airbox, large gaps for the alignment studs. Serial number on the alloy.


As you can see, my AFM has four terminals, the fifth blank.

The new AFM has five terminals

My loom plug has four female terminals, the fifth blank.


My AFM pins x4


x4 wires on loom plug


x4 female terminals on loom plug


My AFM & the new one sat on top showing the pins

[Brianmoooore]

So there is no 3 pin AFM? In that case, a 325i AFM is a 325i AFM, whether it's got four pins in the socket or five. Only four will be connected to the ECU.

Your pics. are a little large!

[svenga]

Apologies I never usually post photos on here.

So how many wires does your loom have Mick?

Can anybody tell me why the new AFM will not work correctly on my car if it is the same on any 325I?

Am I supposed to perform an Ecu reset, anything I am missing?

[magpie]

i'll be at the yard tomorrow and check the one that's fitted to the black 325i turd

[magpie]

this one is looking promising ?

[svenga]

Just am update and closure to this thread.

Mick kindly replaced the AFM with an identical model, this works fine and as it should

Regarding the previous unit being faulty, personally I think it was fine, just not happy on my car and the AFM needed to be specific.

Either way it has not entirely fixed the issue



Onto the fuel side of things now!

Many thanks to everybody who contributed and Mick on an understanding sale as per.

[HairyScreech]

Part numbers say why, the new one is a vauxhall one.

Very similar and I am sure Mick removed it from an E30 but it is not right.

http://www.ebay.co.uk/itm/MASS-AIR-FLOW ... 0884971466

[svenga]

How strange

In between working with Mick I did a small hunt and found a few with the same number stating to be off 325i's, the majority with BMW breakers and one e30 specialist.

So not just mine has had it fitted.. As said it operates fine exactly as the existing one did, only slightly finer if anything. Revs are still low mind, and the initial AFM ran on the car perfectly for atleast two years before the idling issues appeared.

I have clearly inherited a previous owners headache.

Thanks for the link Hairy.