Technical 1.4 MA Turbo Annoying rattle when lifting off accelerator - wastegate pre-load?

[brooking147]

So I have a recently acquired Punto Evo Sporting 1.4 Multi-Air Turbo and am gradually working through a few minor issues.

One thing I have noticed is an annoying rattle that is apparent when lifting off the accelerator. At first I thought this was something like a loose exhaust heat shield but after a bit of a look tonight I think it is coming from the wastegate control rod. I have not removed the heatshield yet but if I grab the rod that comes out of the vacuum valve and move it I can clearly feel a bit of a rattle. A quick Google and You Tube session suggests there could be play in the rod connection to the wastegate. Either shiming the connection point or adjusting the rod to 'pre-load' the gate look like possible solutions.

Before I dive in has anyone had a similar rattle or opinions on what is the preferred solution. Can a gate wear over time thus requiring a pre-load adjustment? Will varying the pre-load have any adverse effect? I have not definitively determined whether the rattle is coming from the rod linkage, or inside the vacuum valve itself.

Any suggestions welcome, thank you.

 

[vexorg]

A small helper spring maybe? and that would give a bit more boost too

 

[brooking147]

A small helper spring maybe? and that would give a bit more boost too

Thanks for the reply.

Is there a difference between a helper spring and adjusting the pre-load? I am only trying to get rid of the rattle, performance seems OK, although I have come from a 1.1 ECO Panda !! The pre-load adjustment seems all over You Tube in various guises, not much about helper springs that I have found and adjustment looks relatively straightforward.

 

[Asteris]

There are dozens of youtube videos that show how to set more preload. I had the same problem when i bought the car and did it myself. Right now you probably lose pressure too and the car does not have full power. Mine felt less that 100Hp before the adjustment. Didn't had any problems since then, for the last two years, as i now installed the 1446 Garrett, to upgrade to the Abarth SS spec...

 

[Asteris]

Use this guide



3-4 turns from zero load is enough...

 

[brooking147]

There are dozens of youtube videos that show how to set more preload. I had the same problem when i bought the car and did it myself. Right now you probably lose pressure too and the car does not have full power. Mine felt less that 100Hp before the adjustment. Didn't had any problems since then, for the last two years, as i now installed the 1446 Garrett, to upgrade to the Abarth SS spec...

Finally got around to doing this on my car. The wastegate was set so that it was very loose and hence the cause of the rattle on lifting off. I found the point where the wastegate was closed with no rattle then adjusted the actuator arm two full turns of pre-load. This has definitely got rid of the rattle which is great! The car does feel like there is a shade more power at lower revs and maybe less lag, but not a dramatic change.

Hopefully moving the arm position from the original setting will not cause any problems. Could it be wear means that this adjustment is required on an older turbo?

Anyway I am very pleased to get rid of the rattle from the wastegate that was really noticeable and getting on my nerves!

 

[thenerko]

Have exact problem on Bravo 1.4T. It is really annoying. Every time going downhill can hear the rattle, also in neutral when shrotly press throttle up to 2,5-3k rpm while rpm is dropping to idle can hear rattle.

And in my case it is definetely wastegate valve rattle. You can simply test it with another person pressing throttle and you keep the arm of wastegate, careful it is hot.

I tried setting preload to neutral position and than undo 2 full turns, but than I had overboost (not engine fault light) but loud "sutututu" surge everytime letting of throttle. So prepared 10 mm wrench, long pliers and take car to a mountain ride and test every half turn of wastegate arm rod, until I got no overboost sound. Right now car has full boost around 2300-2400 rpm so it drives better. When it first come with rattle it had very late boost, almost no turbo boost until 3000 rpm.

So no way of simple rattle fix for me. Now car has same rattle, but at least turbo spool is earlier.

There are available repair sets for some turbos, including new wastegate flap, shaft and outter arm. But turbo needs removing and some welding, since main problem is it become loose at their place.

 

[Brescia]

Generally, over time the wastegate spring can relax/lose spring rate with heat cycling which is normal. Setting the preload is usually the correct fix, save for any excessive erosion of the valve disk, or seat.