Fulvia Speedometer reading too slow
Fulvia Speedometer reading too slow
Hi everybody
I'm new to Fulvia ownership so its nice to find a forum on the subject.
I'm importing a '74 1.3 S2 Coupe from Italy to Switzerland.
I've put the car once thru' the vehicle test here and the main problem was my speedo/tacho is reading too slow. They test the car at 50km/h and the speedo is somewhere at 40-45.
My question is, Is it simple to adjust the speedo? Is there an adjustment screw at the back?
I'm hoping its this simple.
Also related to this how do I remove the dash board to get at the speedo?
Thanks in advance
Simon
I'm new to Fulvia ownership so its nice to find a forum on the subject.
I'm importing a '74 1.3 S2 Coupe from Italy to Switzerland.
I've put the car once thru' the vehicle test here and the main problem was my speedo/tacho is reading too slow. They test the car at 50km/h and the speedo is somewhere at 40-45.
My question is, Is it simple to adjust the speedo? Is there an adjustment screw at the back?
I'm hoping its this simple.
Also related to this how do I remove the dash board to get at the speedo?
Thanks in advance
Simon
Re: Fulvia Speedometer reading too slow
That is quite a difference. I assume you have the correct tires and nobody has put the wrong sender in the gearbox. Most likely the speedometer is faulty. Usually they are quite accurate. Best have it fixed and recallibrated at one revolution per meter.
Is the trip counter still reasonably accurate? If it is, you can safely conclude that the problem is indeed in the speedo.
To get the "wooden" panel off, undo the screw at the back on the right hand side. You can get to it through the glove locker. Undo the two nuts on the reostat and trip counter zero control just above the steering column. You can now get the panel off. Careful with the small knob at the bottom of the clock.
If you opt for buying an other instrument cluster, make sure it is the same make as the one you have. They are either Veglia Borletti or Jaeger.
Is the trip counter still reasonably accurate? If it is, you can safely conclude that the problem is indeed in the speedo.
To get the "wooden" panel off, undo the screw at the back on the right hand side. You can get to it through the glove locker. Undo the two nuts on the reostat and trip counter zero control just above the steering column. You can now get the panel off. Careful with the small knob at the bottom of the clock.
If you opt for buying an other instrument cluster, make sure it is the same make as the one you have. They are either Veglia Borletti or Jaeger.
Re: Fulvia Speedometer reading too slow
Surely the wheels / tyres would be the first thing to check. If the outside radius of the tyres is not as it was originally, then the speedo would read wrongly. Larger diameter wheels tyres would give a lower speedo reading....
Re: Fulvia Speedometer reading too slow
Thanks for the replys guys. It may well be the wheels and tyres.
I have 14" Cromadoras with 185/70R14 tyres. Do you know how that compares to original spec 1.3 S2 coupe equipment?
I would rather change or adjust the speedo if it's possible, rather than change the wheels purely as I like the look of the Cromadoras...Am I asking for trouble?
Many thanks
Simon
I have 14" Cromadoras with 185/70R14 tyres. Do you know how that compares to original spec 1.3 S2 coupe equipment?
I would rather change or adjust the speedo if it's possible, rather than change the wheels purely as I like the look of the Cromadoras...Am I asking for trouble?
Many thanks
Simon
Re: Fulvia Speedometer reading too slow
The diameter of 185/70R14 is in fact a bit less than that of the original 165R14 tire. It should cause your speedo to read high.
Re: Fulvia Speedometer reading too slow
Hello,
strange reaction of the instrument to give lower speed in that conditions ... (smaller tyres).
HAve you got any newer point to tell us where does it come from ?
Personnaly, i mounted smaller tyres on my car, (185/70/13 instead of 175/13), the difference at the speed in very importnat (i couldn't make the ratio with my informations, maybe with the great help of Huib...
sure it gives higher speeds, like 130 km when i would be at a very reasonable speed (somehting like 100 km/h...) 30% is much higher that the supposed ratio of my tyres/normal tyre size, wich surprised me.
the fact is there is a lot of disadvantages to keep this system : bad interpretation, numerous radars to avoid, bad management of the engine, and no way to use it for regularity contests...
i don't see a way to modify this, maybe Huib..... have think of something.
Thibaut
strange reaction of the instrument to give lower speed in that conditions ... (smaller tyres).
HAve you got any newer point to tell us where does it come from ?
Personnaly, i mounted smaller tyres on my car, (185/70/13 instead of 175/13), the difference at the speed in very importnat (i couldn't make the ratio with my informations, maybe with the great help of Huib...
sure it gives higher speeds, like 130 km when i would be at a very reasonable speed (somehting like 100 km/h...) 30% is much higher that the supposed ratio of my tyres/normal tyre size, wich surprised me.
the fact is there is a lot of disadvantages to keep this system : bad interpretation, numerous radars to avoid, bad management of the engine, and no way to use it for regularity contests...
i don't see a way to modify this, maybe Huib..... have think of something.
Thibaut
Re: Fulvia Speedometer reading too slow
If I understand you correctly we have two different problems here. A faulty speedometer and wrong diameter of the tires.
It is best to solve each problem separately. Compensating one problem with another usually backfires.
The diameter of 175/80R13 is 608mm. I am not sure if 175R13 is the same, but it will be close. The diameter of 185/70R13 is 588mm. The difference is 3,3%. The difference in circumference is thus also 3,3%. If you are going at 100 real km/h, the speedometer will indicate 103,3km/h. This is not too bad.
I use ww.toyo.co.uk to find the diameters. They also list a 175/80R13 tire with 310 pattern which is very good. It is at the bottom of the list with passenger tires type 330. Note that they list overall diameters for all tire sizes.
If you are not happy with the error of 3,3%, the solution is to install a small black box with gearwheels to correct the error.
When doing regularity stages I find such an error insignificant. The accuracy should come from tables showing distance (in decametres) and time (in seconds) for all possible average speeds. The distance should then be measured with a Halda Twinmaster or something similar. You can get the Halda accurate to within 0,35%. An error of 0,35% is still significant on long sections. The only way to get rid of this error is to make your own tables using Excel and compensate for the error.
If the speedometer is off for let’s say more than 5%, it needs to be overhauled / repaired. If not, it may continue to go down hill and in the end fail all together. Getting a black box with gearwheels makes no sense as the error may be different every week.
It is best to solve each problem separately. Compensating one problem with another usually backfires.
The diameter of 175/80R13 is 608mm. I am not sure if 175R13 is the same, but it will be close. The diameter of 185/70R13 is 588mm. The difference is 3,3%. The difference in circumference is thus also 3,3%. If you are going at 100 real km/h, the speedometer will indicate 103,3km/h. This is not too bad.
I use ww.toyo.co.uk to find the diameters. They also list a 175/80R13 tire with 310 pattern which is very good. It is at the bottom of the list with passenger tires type 330. Note that they list overall diameters for all tire sizes.
If you are not happy with the error of 3,3%, the solution is to install a small black box with gearwheels to correct the error.
When doing regularity stages I find such an error insignificant. The accuracy should come from tables showing distance (in decametres) and time (in seconds) for all possible average speeds. The distance should then be measured with a Halda Twinmaster or something similar. You can get the Halda accurate to within 0,35%. An error of 0,35% is still significant on long sections. The only way to get rid of this error is to make your own tables using Excel and compensate for the error.
If the speedometer is off for let’s say more than 5%, it needs to be overhauled / repaired. If not, it may continue to go down hill and in the end fail all together. Getting a black box with gearwheels makes no sense as the error may be different every week.
Re: Fulvia Speedometer reading too slow
Thanks everyone for the information. I can see this will be a very useful forum for me.
I have checked around and if I'm correct the original tyres for my '74 1.3 Sport were 165/80R14 which have the same external diameter as the current 185/70R14 on the car.
So I'm still thinking that the error is with the speedometer itself. Unfortunately I've not had any free time lately and am just off on holiday for 2 weeks, so no progress to report. I'll let you all know when I get back and have a look.
Cheers
Simon
I have checked around and if I'm correct the original tyres for my '74 1.3 Sport were 165/80R14 which have the same external diameter as the current 185/70R14 on the car.
So I'm still thinking that the error is with the speedometer itself. Unfortunately I've not had any free time lately and am just off on holiday for 2 weeks, so no progress to report. I'll let you all know when I get back and have a look.
Cheers
Simon
Re: Fulvia Speedometer reading too slow
Hello all,
from my short experience as far as this instrument, once mine putted back on the car, i observed an erratic indication (the needle making quick movements, then staying still on 0...)
slightly moving the aluminium fitting of the command cable back of the instrument would make it work properly (wich means with its actual problem of excessive speed).
a bad fitting of this cable would change the information communicated to the instrument , as is works with magnetic signal ?
I am not sure this is a normal feature on this kind of car,but i discovered that on my car (1st serie), the cable protection was in two parts, connected together by a simple plastic "ring" and collars.
Fitting together these two parts more or less tightly would probably modify the lenght the cable penetrate in the instrument, hence a possible error...?
a good point to check following huib's advices : is the partial km trip works properly, even if the needle not... I will have confirmation soon, but it might occur as described. In that case, what is the conclusion to take ?
I have never heard of gears to modify instrument indication, they must be pretty rare and precise ?
i would also appreciate your experience in repairing instruments mechanism...and some adresses.
from my short experience as far as this instrument, once mine putted back on the car, i observed an erratic indication (the needle making quick movements, then staying still on 0...)
slightly moving the aluminium fitting of the command cable back of the instrument would make it work properly (wich means with its actual problem of excessive speed).
a bad fitting of this cable would change the information communicated to the instrument , as is works with magnetic signal ?
I am not sure this is a normal feature on this kind of car,but i discovered that on my car (1st serie), the cable protection was in two parts, connected together by a simple plastic "ring" and collars.
Fitting together these two parts more or less tightly would probably modify the lenght the cable penetrate in the instrument, hence a possible error...?
a good point to check following huib's advices : is the partial km trip works properly, even if the needle not... I will have confirmation soon, but it might occur as described. In that case, what is the conclusion to take ?
I have never heard of gears to modify instrument indication, they must be pretty rare and precise ?
i would also appreciate your experience in repairing instruments mechanism...and some adresses.