hello there
yesterday i disconnected the tube of the vacuum advance unit while the engine was idleing but nothing happened the engine continued to work as normal
does this means that the vaccum unit is gone?

Just do the "suck and blow" test on it, if it fails it's gone , make sure the hose is not puntured/leaked though

Not necessarily.
Vacuum is almost negligible while idling, which means that disconnecting the vacuum pipe has almost no effect on the advance.
The vacuum/advance changes only after rpm increase. As said before, try to suck the pipe while it is attached to the distributor - if there is a resistance and you can hear a "click" from the dizzy, then it is almost certainly OK.
If you want to be on the safe side, you can disassemble the distributor (mark its position first for later reassembly so that you do not end up with the advance misadjusted) and see whether the rod is moving while you suck the pipe.

Hi All,

On my 1.0IE Uno, If I disconnect the vacuum advance pipe when idling the revs drop loads, and the engine is close to stalling. It sounds a bit like its running on 3 cylinders.

When I replace the pipe, the revs pick up again, and all is OK.

I’m not sure if this is the same for the carb set-up BTW.

As said before I’d fry the Blow test on the pipe.

Regards,
Louie.

Yes, daz rite.
What I said applies to carb models only. No proven idea about how it works on injection .
I am sure there are many much wiser men to shed light on the Jetronic systems

(CZ)enda said:

Yes, daz rite.
What I said applies to carb models only. No proven idea about how it works on injection .
I am sure there are many much wiser men to shed light on the Jetronic systems

Click to expand...

When i disconnect my vaccum advance pipe when at idle it drops its revs, and mines a carb

Mine's a carb Uno, and removing the vacuum pipe makes the engine want to stall.

The reason for this that the timing goes out, because no vacuum is pulling on the vacuum advance unit.

What some people with a duff advance unit do is adjust the timing until the engine runs smoothly. If the ignition is set correctly the engine will only tick over reliably with the vacuum pipe connected.

Check to see if you vacuum advance unit is function correctly before checking anything else.

Chas

Uh-hm.
When I disconnect vacuum pipe while idling, nothing happens.
Dizzy advance membrane works as it is supposed to.
I had the timing checked with stroboscope some 7 years ago, never bothered to have it re-checked.
Have I been driving my Uno for 7 years with the advance misadjusted ?

(CZ)enda said:

Uh-hm.
When I disconnect vacuum pipe while idling, nothing happens.
Dizzy advance membrane works as it is supposed to.
I had the timing checked with stroboscope some 7 years ago, never bothered to have it re-checked.
Have I been driving my Uno for 7 years with the advance misadjusted ?

Click to expand...

What may have happened is they didnt disconnect and block the vaccum pipe when adjusting the timing

With the engine running, pull the pipe off the distributor and put your finger over the end of it. If it's sucking and the vacuum advance unit is working fine, then I'm not sure what to suggest.

You could take off the dizzy cap and check to see that the base plate actually moves when you apply vacuum to the diaphragm. If that is working, then the only thing left to check is the timing if you haven't done so for the last seven years!

Best of luck.

Chas

Hello, I have now replaced the vacuum advance unit on my car 5 times since buying the vehicle 5 years ago. Seems like the vacuum unit works fine for a few months then fails. I have installed a fan that blows directly onto the distributor/advance but that hasn't resolved the problem. Could something be causing the vacuum advance to fail? too strong vacuum maybe? Any suggestions would be gratefully received.
Fiat Uno Mia, 1100cc, 2000 model with 11000km on the clock, bought used about 5 years ago.

If the distributer is a Magnetti Marelli unit, the auto advance does not last very long.

BasilA said:

Hello, I have now replaced the vacuum advance unit on my car 5 times since buying the vehicle 5 years ago. Seems like the vacuum unit works fine for a few months then fails. I have installed a fan that blows directly onto the distributor/advance but that hasn't resolved the problem. Could something be causing the vacuum advance to fail? too strong vacuum maybe? Any suggestions would be gratefully received.
Fiat Uno Mia, 1100cc, 2000 model with 11000km on the clock, bought used about 5 years ago.

Click to expand...

the vacuum , should alter the timing under varying engine conditions,
the fitting of a fan will give a fixed output..!!:bang:

remember that any rubber parts in an item built 15/20 years ago will be past their best now..,
Charlie

I had my hole engine block reconditioned 3 years ago and fitted a new distributor, coil and ht leads, but once again this weekend the vacuum advance mechanism has self destructed inside the distributor bending the top plate and breaking the arm off that connects it to the vacuum diaphragm and ripping off the earth wire, I have a theory that the vacuum may be influenced by a faulty exhaust system. If the back pressure is not correct on the exhaust sytem could this affect Vacuum? any one know ?