MPG / MFA not working proberly.

Hi

I hope someone out there can help me out with this problem.

My car is a GTI from 83

My MPG needle in my clock/speedo isnt reacting as it should. It comes on when i shift into 5th gear, but first after a few miles in 5th gear.

And even then its not showing the correct info. I can be in 5th gear, no throttle at 50 kmt and it shows between 9 and 11 L/100 - This cant be right.

Is it only the vacuum line from the clock/speedo to the front intake that meassures this ? Or are there other parts included ?

Not sure if its a related issue, but my trip counter + L/100 + KM/hour in my MFA isnt reacting aswell, it just shows - - -

Hope someone can help, its driving me nuts

your mfa speedo sender is missing or broken, this is what makes the avg speed and distance settings work and these are essential for the mpg gauge to work properly.

take the clocks out the sender is on the rear of the speedo, easy to swap held on with 2 screws. if a new one doesnt help its the PCB thats gone or the speedo itself, theres a speed ring in the back which can fail had same issue in a set of clocks in my mk1

Alright, i will check that right away.

Might have a spare speedo someplace.

Whats PCB ?

short for "Printed circuit board" mate, the blue flexible plastic with the electrical circuit embedded in it, they get damaged sometimes

Can my reverse switch light have anything to do with this ?

not the speed reading no, that should work regardless of the condition of the switch. the reverse switch just tells the cluster when you are in 5th. that appears to work since the needle actually moves!

Alright, ill save those money then.

ill check the vacuum transistor on the back later today.

A another question while we are at it, does the milimeter size of the vacuum tube from the clock to the brakecylinder matter ?

Iknow its a 2mm from stock, but ive fitted a 4mm both there and from the vacuum on the distributor to the throttlebody !? Do you know if that would have any influence?

it may do, but the main reason it isnt working is because you have no speed signal into the cluster, sort that first and work from there

Alrighty - Grazie

I will give it a go and post abit later !

I switched the vacuum transister - no difference

I switched the whole MPG gauge in the clock out with a different one, no reaction.

Needle still jumps random around and MFA says - - -

           

Changed all the vacuum tubes out for 2 milimeter ones. didnt help either

But all the fiddeling has made the needle go to the lower end of the MPG gauge which it didnt before.

Someone says it also could be the reverse light switch since it also has something to do with consumption?

MFA still says - - - … Baaaha (((

like I said, check the speedo and the speed sensor in the back of the speed. until you get the distance and speed settings working on the MFA you wont get anywhere

the vac sensor only runs the mpg gauges, but it wont have any affect on the speed/distance settings, the vac sender was working I think since the gauge moved a little bit?

the reverse switch only tells the cluster you are in 5th, and so the needle moves as theneedle gauge will only work in 5th. the digital mpg gauge will work in any gear, once the distance/speed settings work

Hmm, and where do i find this speed sensor ?

Is it the place with PCB squezzed together with 2 screws on the back on the trip/miles counter ?

thats the one

Rubjonny .. you are the man!

Everything works now, after i messed around with that PCB part and made sure it actually touched the connectors, it actually works now.

Glad i saved those money on the reverse light switch!

Thanks a million for the help!

sweet

Hi Rubjonny
must have hit the wrong button as my message has shown in the wrong box ! hope that you can understand it , similar issue as Mark, confused readings ? speedo fine , i will remake the contact as per Mark , is the speed sensor available ??
Cheers Colin

on its own not easily, try to get another set of clocks you can try one from. you may find its the clocks themselves or the speedo that has gone so its well worth having a full set of clocks to swap bits over from. just make sure its the same type/make as yours as vdo parts differ from motormeter

Hi mate, since posting i removed & replaced the sensor as you advised to Mark replaced the unit and now i have mfa readings that seem to be correct but still no rev counter , speedo is fine , on ebay last night i bought a set of clocks for this same model with almost corresponding numbers so i hope that it will do the job , is the speedo sensor available as a spare part ? thanks fo the contact Colin

they're NLA from VW but the same one is used in mk2 golf clocks if you're stuggling to find one