Interesting MFA Diagnostics result for KR 16v

[boost monkey 0]

Ola boys and girls,

 

I've just been fiddling with my vac pipes on the MFA / Intake to try and get my MPG to read accurately (maxes out at 12.5mpg :cuckoo: ) and while I was there I thought I'd write down what values I got in Diag mode on the MFA. Please correct me if I'm wrong with labelling the values:

 

3 - Country code UK

955 - some rev counter value, factory idle speed perhaps?

7418 - upper rev limit (hard limit I'm guessing as it's pretty high!)

1175 - lower rev limit (not actually sure what this is used for, warm-up idle speed perhaps?)

74 - oil temp?

Segment test - works OK.

107 - reading the bentley this seems to be something to do with engine map, but I'm not sure what.

 

If anyone can enlighten me to whether these figures are all in keeping with a good MFA unit and it's associated sensors that would really help me out.

 

Cheers,

 

Jon :salute:

[kaiserVR6 0]

How do you get the MFA into diag mode?

 

I need to sort my vac pipes out too, mines states 99.9 mpg, i wish this was true but unfortunately not!

 

Need to figure how to get the dash out really!

 

Let me know how you get on

[davidwort 0]

955 - some rev counter value, factory idle speed perhaps?

 

 

that should be the current revs!

 

I can't remember exactly how to do it, isn't it ignition off, hold mfa button in, ignition on, ignition off, start car, release mfa?

[Riley 0]

^

 

With car running flick mfa to position 2.

Hold in end button and tuen ignition off and restart straight away.

Release end button.

 

Neil. 8)

[boost monkey 0]

Position 1 works too Neil, that's the one I used. I think Position 2 gives you instantaneous readings? digital rev counter etc etc etc.

 

@Davidwort, The car wasn't on when I did it, so maybe it took the lowest rev value from when it was last on? Would have been about 2 mins before when I was checking the rev counter for something else!

[boost monkey 0]

How do you get the MFA into diag mode?

 

I need to sort my vac pipes out too, mines states 99.9 mpg, i wish this was true but unfortunately not!

 

Need to figure how to get the dash out really!

 

Let me know how you get on

 

It's really quite simple. On the KR, there is a vacuum line that Tees off by the airbox on a Y-shaped red plastic connector. It's a black hard plastic hose (as opposed to the see-through ones) and it goes through the bulkhead just to the right of the brake servo.

 

This then joins to a black rubber hose which attaches to the back of the MFA unit on the dials. I pushed this rubber pipe further onto the join on the dials, it was all I could do, as all the other pipes were intact :shrug: You can check the dash pipe from the driver footwell after you take the large lower dash trim panel off (under steering wheel, and above pedals)

 

I hear that a mpg reading of 99.9mpg means your MFA unit might be on the way out. Maybe new clocks time? Otherwise, let us know how you get on.

 

btw, to get the dials out, there are two screws located bottom left and bottom right of the surround as you look at it, then there are two up in the top edge ^ of the surround going upwards (you can't really see them unless you're in the footwell). They're all kinda prone to falling out whilst undoing and getting lost somewhere, but hopefully you will be ok.

 

Once you get these four screws out, you can remove the surround. The dials are then held in by two free-swinging pivots at the bottom (don't worry about these) but the top left and top right corners are screwed into place, so you have to undo these. These two are the ones most likely to fall out and get stuck behind the dash somewhere! After these two are out though, you can move the clocks forward, but remember to disconnect the speedo cable else they won't move too far, and you don't really wanna pull the cable apart.

 

:salute:

[kaiserVR6 0]

boostmonkey your a legend, i'll have a go at that if i get my headlining retrimmed, wheels on and car whashed and polished before Volksfest!

 

:D

 

i'll keep you posted

[vwdeviant 0]

Remember DON'T lost the two screw covers at the bottom corners of the dash as they're not available from VAG anymore, and a ROYAL PITA to find second-hand!

[boost monkey 0]

Goodo :grin:

 

Went for a run in my car this avo ro see if the mpg is sorted, and it isn't....yet. I'm thinking I may have a blocked pipe or something, after all they are prob originals!

 

I think I will pull them all off and clean/replace them at some point. Mileage and fuel guage are showing that i'm doing reasonable mileage so that is ok :dorky:

[stemid 0]

hmmm interesting,

 

my mfa has been working fine, but then on a run up to london a while ago the mpg kept creeping up an up slowly, i thought i was on to a winner, driving really economically! however once i got past 50 mpg i realised something was wrong. kept goig until it reached 99.9

 

now it's hovering around 14-15 mpg. even if i'm cruising at 40 with low rpms and do the mfa reset, the mpg still returns back to around that mark.....

 

any ideas?

[Yandards 0]

The MFA inputs that give you the average MPG are based on a vacuum sensed load that comes from (on 4 cylinder cars) the vacuum servo hose non return valve, this then connects to a vacuum sensor on the back of the clocks, these are model dependant and are also matched to the clocks (ie a 16v VDO one needs a 16v VDO vacuum sensor).

 

The MFA takes the vacuum reading, road speed reading and RPM reading and throws out an average MPG. The most likely causes of a bad MFA reading are a hole in the hose or the vacuum sensor on the way out, not a new set of clocks. To access the back of the clocks the procedure is to remove the clocks surround trim (4 x screws, 2 under the plastic covers that break and you cant get new anymore) then remove the clear plastic fascia from the front of the clocks. this will allow you to tilt them forwards without scratching fascia, it also lets you access most of the clock internals without the need to remove them from the car. If you need to get to the back of the car then undo the other 2 screws and tilt the clocks forwards, pull the vacuum hose, electronic plug and speedo drive cable (early 16v and G60s only, you will have a mechnical mileage/trip counter not digital if you have a speedo drive cable) and you can them remove the clocks.

 

As for the MFA diagnostic mode it works in both position 1 and 2.

 

Position 1 is called check mode and you enter it by putting the MFA slide switch in position 1, switch on the ignition (not start) hold down the MFA button and turn the ignition off and on again whilst holding down the MFA button, finally release the button.

 

The first piece of info you get is the engine map code (KR is 107, PG is 026, 9A is 041, ABV is 039).

Press the MFA button and the next item is the country version code (3 is UK).

MFA button again and you will get the speedo drive ratio (All Corrados should be the same value of 950).

Next item is the upper speed limit, this is a complete nonsense figure as all Corrados should show 7418.

Lower speed limit, again a nonsense figure as all Corrados should show 1175.

Overrun cut off vacuum, listed a nonsense figure although KR is 255, PG is 320, 9A is 300 and ABV is 220.

The last press will turn on LCD blocks on the MFA to test them.

 

To get back to a normal MFA, simply slide the switch to position 2 and back to position 1, please note you cannot enter diagnostic mode 2, measuring mode, without carrying out the MFA slide switch to position 2, ignition on, hold down the MFA button and ignition off and on again; this mode is more useful with the engine running. Modes are as follows:

 

First information displays a test sum of programmed bytes and is nonsense.

Next you will get Intake manifold vacuum in mbar/ a decimal numerical value (A good range is 15-255 for a 16v and 7-127 for a G60 in decimal; both ranges correspond to 100-1100 mbar)

Engine RPMs

Momentary fuel consumption

Speed sender impulse (this is the speed at which the speedo cable/gearbox speed electrical sender is working at and derived from speedo drive ratio from mode 1 x constant x distance travelled in miles for a UK vehicle) As long this goes up and goes up faster when you are driving quicker its good ;)

Engine oil temp

Ambient air temp

 

I hope that clears all of that up!

[boost monkey 0]

Really comprehensive as usual Yan, cheers :salute:

 

So my vac reading of 75 is ok as it's the 'intake manifold vacuum in mbar'? That's good to know. I'm thinking maybe my MMPG is getting thrown out by the rev counter then cos it's very sporadic and jumps all over the place.

 

Is this symptomatic of a bad ground or just a dodgy connection? I'm 99.9% sure the signal lead is the one with the 2 white single wire connectors on that hangs out around the coil, but they're seized together. perhaps the contacts have corroded, which is why the needle jumps around (~500rpm either way from proper value...only on occasion though) and why i can't get them apart!

 

Bay needs rewiring anyways, so If it' a dodgy wire I'll leave it for now... dodgy tach isn't an MOT fail is it? :scratch:

[Kempy 0]

hello

Sorry to bring up something fairly old. My 9a mfa has the time on 48.11 and the other which is some sort of milage around 1200 how do I reset these figures? I couldn't find the mfa reset info earlier in the thread.

cheers kempy

 

Edit: I've just found out how. I always thought they were rear wiper settings...LOL what an idiot :cuckoo:

[boost monkey 0]

to reset the clock i'd just disconnect the battery, probably easiest/only way.