Technical Econometer

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Technical Econometer

Mennywise

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Hi, my name's Matteo, i'm 21 and I write from Italy and i have found this fantastic forum!! I have an Uno 60S Smart (1116cc carburettor) and would like to ask you for a problem. My econometer works only from the yellow to the red, even releasing the accelerator. Turning off the engine it goes correctly under the green. The T pipe connected to the brake servo seems ok. What i can i do? Thanks!:)
 

Louie Bee

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Hi Matteo and Welcome to FF!

Have you seen the gage work properly since you have had the Uno?

Regards,
 
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Mennywise

Mennywise

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This problem started about 2 years ago...the econometer is electric i think..the T pipe goes at a "fungus", wich has a connector with 2 wires, going to the dashboard...
 

Louie Bee

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Sorry my Italian isn’t too good (well non existent really :eek:). I’m guessing the "fungus" is a sender :).

Chas (1986Uno45S) is our resident econometer expert. See from post 6 here https://www.fiatforum.com/showthread.php?t=38974 it may just be out of adjustment.

Perhaps there is more to it, have you seen a decrease in fuel economy since the problem occurred? I’m not familiar with the 1116 set-up. Perhaps it's one for Alex, Chas or another of our budding experts ;).


Nice Avatar by the way (y).
 

sumplug

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the econometer on unos were notoriously unreliable. its basically a vacuum guage. they go faulty and will mis-register. a new guage is the answer sorry.:)
 

Louie Bee

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sumplug said:
the econometer on unos were notoriously unreliable. its basically a vacuum guage. they go faulty and will mis-register. a new guage is the answer sorry.:)
Not necessarily ;).

As suggested in my above link they can fall out of adjustment (High or low reading), or lose electrical connection (no reading e.g. bad earth, broken wire).

The aspect I’m not sure about is if there is an underlying tuning issue, or a solenoid / cur off valve which is malfunctioning around the carb its self :eek:.

Night All,
 

sumplug

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well its usually the guage or sensor gone. earthing wires will tell. my guess is its the guage. my uno 45 ES went through 3 guages in 18 months.:)
 
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I've only ever had one econometer fail on me, and that was my fault! I poked a wire into the wrong place on the dashboard plugs and blew the sender. Other than that I've never had any problems with them.

Mennywise, I think yours just needs adjustment. This can be done on the sender unit, which is normally bolted on the right hand front suspension tower (facing the front of the car), though I've also seen them bolted to the middle of the bulkhead/ firewall, to the left of the washer reservoir.

Check the link Louie gave. I think I mentioned how to adjust it in there.

They really are a very simple device. They take vacuum pressure from inlet manifold to brake servo pipe via a 'T' piece, and feed it to a simple potentiometer device. This then converts it to an electrical signal and sends it to the gauge on the dashboard. They tend to be very reliable as long as you don't short any of the wires out!
 
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Mennywise

Mennywise

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well...first of all...thank you all!!! :)
It really could be a bad earth, like Louie wrote..I have to say that turning on only the dashboard, the econ did not go to the max; giving electrical spry on the fixing bolt i resolved the problem, but at engine working the needle continue to work from the yellow.:bang: Anyway the indication of the econometer, where it works, is correct. I've seen a screw on the top of the sender, but seems sealed...Is there another earth to check?

regards
 
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Mennywise said:
well...first of all...thank you all!!! :)
It really could be a bad earth, like Louie wrote..I have to say that turning on only the dashboard, the econ did not go to the max; giving electrical spry on the fixing bolt i resolved the problem, but at engine working the needle continue to work from the yellow.:bang: Anyway the indication of the econometer, where it works, is correct. I've seen a screw on the top of the sender, but seems sealed...Is there another earth to check?

regards

The screw on top of the sender is locked by a lock nut. Undo the nut, then you can adjust the screw. When done, nip the lock nut to keep the screw from turning. :)
 
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Mennywise

Mennywise

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uhm...i see only a screw, "drowned" in a substance hardened...i tried to rotate the screw but i only risk to ruin it...i don't understand:confused:
 
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Sounds like the 'substance hardened' is some kind of glue or gasket cement. Maybe someone has already adjusted it and used some kind of glue to hold it in place? Or perhaps its been damaged and the 'substance' is used to stop the screw falling out, which might also explain why the reading is wrong :chin:

All the senders I've seen are just a screw and a lock nut!

First thing I would do in your case is to get this 'substance' off. Cut it, scrape it, chisel it (gently) or whatever. You need to find out what's underneath. It could be something as simple as the nut was lost and glue was used instead to hold the screw.

See if you can remove the substance and find out what's underneath. Then let the board know what you find.
 
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Mennywise

Mennywise

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1986Uno45S said:
Sounds like the 'substance hardened' is some kind of glue or gasket cement. Maybe someone has already adjusted it and used some kind of glue to hold it in place? Or perhaps its been damaged and the 'substance' is used to stop the screw falling out, which might also explain why the reading is wrong :chin:

yes..a kind of glue or something similar...(sorry for my english:p )...anyway this element has never been repaired or adjusted... I found this image on the web

enginebay.jpg


my car has exactly this same engine, and the same sender that you can see near the water box, on the left..only the brake servo seems to be placed differently, the mine is at the right of the waterbox..
Anyway, tomorrow i will take a photo of it and will post it here...i have the sospect that could be a semplified sender...is it possible?thanks again..CIAO!:D :D
 
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Mennywise

Mennywise

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Here's the photos of the sender...
Immagini coso 002.jpg

Immagini coso 008.jpg
The screw is on the top..into the hole...and under the sender you can see the connector (3 contacts and 2 wires:confused: ...is it normal?)
Any ideas?
Thanks.:D
 

(CZ)enda

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Mennywise said:
Here's the photos of the sender...
(3 contacts and 2 wires:confused: ...is it normal?)
Any ideas?
I believe it is, mine has 2 wires as well.
 
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Louie: I think the 'fungus' was in reference to the mushroom-shape! :)

Chas: I'll leave it with you, since I've never fixed one... but my first thought is:

- before you adjust the econometer sender, are you sure there is not a vacuum leak in the pipes leading to the sender - or even anywhere in the vacuum system - e.g. the distributor vacuum advance if that is T'd into the same pipe (I don't think it is, but worth a check?)

I'm not sure if the needle is supposed to actually go into the green zone unless the engine is over-running (i.e. going down a hill with a gear selected). The Uno handbook suggests that with the engine idling, the pointer should be between the yellow and green zones (I've attached a scan of the relevant page).

Cheers,
-Alex
 

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Mennywise

Mennywise

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alexGS said:
The Uno handbook suggests that with the engine idling, the pointer should be between the yellow and green zones (I've attached a scan of the relevant page).

Yes, but in the past it was on the green when idling. Anyway it never goes under that level (exactly between green and yellow)... it's stable, fixed, like if was the minim...do you think there could be a problem in the cut out valve? (e.g. bad earth?...i'm going check all earths)

Thanks by the way, Alex!!:)
 
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Well another thought... the gauge may be connected with the fuel-cutoff device fitted to many Uno 60s and 70s. So, check the wire that connects to the idle-adjustment screw on the carburettor. That tells the cutoff control unit that the throttle is closed. It may be that this also affects the gauge.

-Alex
 

Louie Bee

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A Har Alex :). That’s the thing I was thinking about :D. I don’t know much about the non FIRE OHC engines.

:chin: Would you see a decrease in fuel economy it this cut-off circuit was defective?
 
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