Technical Engine Jerking

[BasilA]

Hello. I have a 2000 Uno 1100 with 40,000 KM on the clock. It was previously owned by a lady who seldom used it. I find the engine to be very jerky especially when going uphill behind traffic and cruising at a slowish speed with constant throttle..; almost like a miss, but more regular. Changing down and accelerating removes the jerking. I have done the following: Replaced spark plugs, plug leads, air and petrol filter, amplifier and pickup in the distributor as well as new rotor and cap. I have replaced the vacuum advance unit as well as the pipe and checked all vacuum connections. Of course I have changed the oil filter/oil. Timing is spot on. I have put in upteen bottles of fuel cleaner etc but without success. Only thing I haven't changed is the coil. Varying the air/fuel setting on the carb seems to improve/worsen the condition, especially the smoothness of the idle. Any suggestions would be much appreciated. Thanks, Basil

 

[rawill]

Yes - First I'd make sure it wasn't carboned up.

Take it for a good thrashing, near redline in lower gears 2nd,3rd, and see what comes out the exhaust. If it burns lots of clouds of blue, kicks around abit then you know what is happening. Hold it at higher revs in 2nd, then back off, up and down through the rev range till it burns and runs cleanly.

This is no an unusual problem on some lady owner cars, Truimph PI's were especially bad. Tune ups would never fix them but the apprentice tune up down the local road did. Customers went away happy and us apprentices thought it was great.

I will look on here with interest, I don't promise this is what is wrong but from where you say you got it I wouldn't be surprised.

 

[BasilA]

Yes - First I'd make sure it wasn't carboned up.

Take it for a good thrashing, near redline in lower gears 2nd,3rd, and see what comes out the exhaust. If it burns lots of clouds of blue, kicks around abit then you know what is happening. Hold it at higher revs in 2nd, then back off, up and down through the rev range till it burns and runs cleanly.

This is no an unusual problem on some lady owner cars, Truimph PI's were especially bad. Tune ups would never fix them but the apprentice tune up down the local road did. Customers went away happy and us apprentices thought it was great.

I will look on here with interest, I don't promise this is what is wrong but from where you say you got it I wouldn't be surprised.

Thank you for your response. I'm going to use this s an excuse to go for a really good thrashing.... regards.

 

[jjhepburn]

You just need to drive like an italian Lots of revs and blasting on the horn thats what they were designed for.

 

[BasilA]

You just need to drive like an italian Lots of revs and blasting on the horn thats what they were designed for.

OK - Did just that. What a difference it has made to the car!!! And I had a great outing as well. Thank you to all of you for the suggestion. Regards. Basil

 

[rawill]

LOL, Great stuff. I wonder what helped, the thrashing or tooting the horn like the Italians.

Anyway with all your good work done on maintenance it should be good for ages now.

 

[robi1nz]

You dont say wheather or not it´s carbed or injected. but the bet is same problem i had. which is vacuum leaks. especially the vaccum pipe from the carb or inlet manifold. rubber aint wot it used to be and perishes & goes hard over time. buy yourself new 3 mm vacuum tubing a few new t junctions and start from there you shouldn´t need any more than 2 meters (2 1/4 yards) if that doesn´t do the trick then have a look at the carb base or all other places that use vacuum ie brake booster hose, breather pipe etc.

 

[robi1nz]

You should see what they´re like in brazil mate crazier than we are. everybody thinks they´re Ayrton Senner. 80 kmh and thats just in the city centre. and fiat heaven you name it they got it. Hows life back in godzone?