Technical Uno 45S

Currently reading:
Technical Uno 45S

nay27uk

New member
Joined
Aug 30, 2005
Messages
57
Points
21
Hi all I just got my first uno 45S its a g reg its done 145.066 miles and runs great its got a great big bore exhaust on it, that makes a right racket. Anyway. i was wondering its got a little meter in the dash named ECON, that as soon as you start the engine, is right at the end of the yellow, almost in the red, was wondering if this is some sort of ecomomy gage to tell you how mutch peterol you are using, and if it should be in the green section untill you floor it, if it should be in the green, can somone please explane to me why it is in the yellow.
THANKS in advance.
A new fiat uno lover.

P.S i also ad the temprature gage does not move could it need a new temp sensor
 
Last edited:
yeah its an economy gauge, i have one in my 45 but it doesn't work :(

in my owners handbok it says:

needle in red zone-excessive fuel consumption

needle between yellow and red zones-medium/high fuel consumption

needle in the centre of the yelloow zone-low fuel consumption

needle between yellow and green zones-engine idling or decellerating slightly

needle in the green zone-engine braking
 
Thanks for thgat info it helps me get an idea of how it should work
 
nay27uk said:
Thanks for thgat info it helps me get an idea of how it should work

im jealous that yours works, not that you really need an eco gauge on an uno 45, i bought mine on saturday and drove it back 100 miles and it only used an 1/8th of a tank, my other car is a 2.0 tipo so i think i will be driving the uno more often now :D :p :D
 
nay27uk said:
P.S i also ad the temprature gage does not move could it need a new temp sensor
It could be the sensor, check the wire hasn't come off it and it is making a good conection! it could also be the thermostat stuck open so the water is taking a long time to get warm! depends on how long you have had it running for realy

HTH
Dan
 
Yes, the 'ECON' gauge is an econometer, or to be more precise a vacuum gauge. It measures vacuum in the inlet manifold to show how much the throttle is opened compared with engine load.

When you start the engine and leave it ticking over, the gauge should be to the left in the green sector. As soon as you drive off the gauge should move towards the yellow sector, and if you floor it it will move into the red.

At cruising speed the idea is to keep the gauge in the yellow sector, or if at all possible in the green. I find on a flat road, in 5th gear at about 70mph it will sit at about the three quarter mark on the yellow sector.

The heavier the load on the engine, i.e. flooring the throttle in top gear or hard acceleration, the further into the red the gauge will go.

As Dazzdog mentioned though, the 45 doesn't really need an econometer as it's pretty frugal however you drive it! However, drive with an eye on the econometer and you'll be amazed at what fuel consumption you can achieve. Recently I did 400 miles (mainly on a long run of 300 miles) on £26 of fuel. I worked out that my little old Fiat was doing 62 mpg!!!!! :eek: (y) I tried to keep out of the red zone and was rewarded with fuel consumption that would shame a lot of modern cars.

If your gauge is pointing the yellow/ red sector at tickover then something is amiss. It should be pointing low down in the green sector. There is a little sender unit for this, which is normally located next to the coil. It has two wires coming out of it, plus a vacuum pipe that runs to a t-piece connected the inlet manifold to brake servo pipe.

First thing to check is that the vacuum pipe is not split or leaking. If it's ok then you can try adjusting the sender.

On the top of the sender you will see an adjusting screw and locknut. With the engine at tickover, loosen the nut and turn the screw until you get the ECON gauge pointing low into the green sector. If the gauge reads higher when you turn the screw, turn it the other way! If this doesn't work, then the sender is probably faulty. If it does work and the gauge is adjusted, tighten the lock nut and check the gauge operates correctly under normal driving.

As for your non fuctioning temperature gauge, first locate the sender, which on the FIRE engine is located on the back of the engine block, near the alternator.

With the ignition on, remove the senders wire and earth it on the engine block, or connect a piece of wire to it and connect it to the battery negative '-' terminal. If when the wire is earthed the gauge shows maximum, then the fault is with the sender. If the gauge DOESN'T move, then either there is a short in the wire from the sender to dashboard, or the gauge itself is faulty.

By the way, welcome to the realms of mk1 Uno ownership! They are cracking little cars, and it's nice to know my 86 mk1 has others on the board for company (y)
 
Oh, and here's a pic of my mk 1 SX dashboard with econometer (the gauge just above the steering wheel Abarth badge. Apologies for those that think non Abarths shouldn't be fitted with Abarth badges. The badge brightened up the otherwise plain black SX steering wheel centre, plus I think it looks good - so there!
 

Attachments

  • Dscf0025.jpg
    Dscf0025.jpg
    419.5 KB · Views: 59
Last edited:
thanks 1986uno45s the info you gave me is top dog now i know what to do i can start geting it sorted
 
I think it's quite possible for the temp. gauge not to register if the FIRE engine has a stuck-open/hollowed-out thermostat... so, perhaps leave the engine idling for a long period (ten minutes at least) to see whether the radiator fan cuts in and out - assuming that the fan is working, this will tell you that the engine has warmed-up, and if the gauge still doesn't register, then the gauge or sender is faulty...

1986Uno45S (Chas), is it possible that the economy gauge has an electrical override (like BMWs have) so that with the engine idling, the gauge moves to yellow? It seems strange that FIAT used an electrical sender - I think a mechanical vacuum gauge would have been cheaper - and I wonder if it was done so that the gauge could be cut-out when the car is stationary and hence fuel consumption is infinitely-high?

Since you have an economy gauge and I've never seen one working, I guess you know how it's supposed to work (y) but I just thought that sitting still with the engine idling is a rather low number of miles-per-gallon, and this is probably why BMW chose to deactivate their vacuum gauge below 20km/h.


EDIT: I've just realised that another likely cause of the gauge not hitting the green is a vacuum leak in the distributor advance capsule, or a split in its pipe...

-Alex
 
Last edited:
alexGS said:
1986Uno45S (Chas), is it possible that the economy gauge has an electrical override (like BMWs have) so that with the engine idling, the gauge moves to yellow? It seems strange that FIAT used an electrical sender - I think a mechanical vacuum gauge would have been cheaper - and I wonder if it was done so that the gauge could be cut-out when the car is stationary and hence fuel consumption is infinitely-high?

Since you have an economy gauge and I've never seen one working, I guess you know how it's supposed to work (y) but I just thought that sitting still with the engine idling is a rather low number of miles-per-gallon, and this is probably why BMW chose to deactivate their vacuum gauge below 20km/h.

Hey Alex, this is a little Fiat we're talking about here! No way does it have the electronic wizardry of a BMW :p

By the way, a BMW joke:

Question: What's the difference between a BMW and a Porcupine?

Answer: A Porcupine has the pricks on the outside :D :D :D :D :D

Anyway, back on track...

No idea why Fiat chose to use an electical sender for the econometer. Especially as it uses a vacuum pipe anyway to link the sender to inlet manifold. They might as well have used a mechanical gauge and sent the vacuum pipe straight to the gauge rather than messing around with extra wires and senders.

There definitely doesn't appear to be any kind of cut-off for tickover. It's only a simple carburetor car afterall.

There are only two wires going to the sender, one is obviously the power coming from the gauge, and the other is the earth wire. The sender simply acts like a potentiomenter depending on the vacuum, hence in actual fact the ECON meter is actually working as a volt meter! The sender varies the voltage depending on vacuum pressure and this is read by the electronic gauge. Very simple in principle and works fine in practice.

Also, at tickover the vacuum is going to be high in the inlet manifold because the throttle valves will be shut (other than the idle air jet), so it will still read low down on the green sector. Only when the throttle valves are opened will the vacuum change and move the needle towards the yellow and red sectors.

So really there is no need for an override, as it's not measuring MPG but simply manifold pressure.

But though the FIRE engine is so economical however you drive, I have occasionally done long journeys and tried to keep the ECON meter out of the red sector. I did a very long trip like this about a month ago, and managed 400 miles on a tank of fuel (£27). A rough calculation showed I was getting over 60mpg :eek: (y) , and still managed to have a cruising speed of 70 - 75 mph!

If you keep an eye on it, it can make an economical car even more economical (y)
 
Back
Top