Technical Turbo valve actuator rod doesn't move

[robbie-rocket-pants]

I've been having a blitz on my Stilo's faults and with your help I'm down to the last one...

The car (1.9 JTD MW) drives fine until I rev to 2600rpm when I get the "Engine Fault" light and bing bing bing. It still drives OK and as soon as the revs drop the fault clears.

Having searched on this site for hours about the EGR, MAP, MAF and overboost solenoid valve, I decided to check the turbo valve actuator - I got Mrs Wife to rev the car to about 3500rpm but I could not see the actuator rod move at all. I checked to see if I could move it by pressing with a screwdriver and it seems to move OK.

So I think the cause of the fault could be that the overboost solenoid valve is not working (I have previously relocated it to the side of battery)

Before I go and buy a new one:
1. Do you clever people think I'm barking up the right tree, and
2. Do you know what voltages to expect on the overboost valve's connector and at what rpm should signals be sent to it ?

I'm going to donate now for all the help I've received from this site

 

[keviwal]

Hi,
have you checked the pipework to and from the boost valve and from the turbo?
You really have to check it very very carefully as the tiniest leak will cause the actuator not to move.
If you have the plastic type pipe i would change it to a neoprene type as it does seal better then the plastic stuff
Let us know how you get on.


cheers

Kev W

 

[robbie-rocket-pants]

Thanks Kev.
I've checked the pipes and as far as I can see they all look OK, but I didn't manage to look into the black box that the pipes go to behind the engine. If I replace them with neoprene pipes do you know what diameter I need to get and where to get them from ?

 

[keviwal]

Thanks Kev.
I've checked the pipes and as far as I can see they all look OK, but I didn't manage to look into the black box that the pipes go to behind the engine. If I replace them with neoprene pipes do you know what diameter I need to get and where to get them from ?

Hi,

You will need about 4.5mm bore tube. If you are really struggling pm your adress and i might have some kicking around

Cheers

 

[robbie-rocket-pants]

Here's an update:

I pulled the blue tube off the end of the turbo actuator and put my finger on the end. I noticed there was very little vacuum even when the engine was revved hard. So I removed the boost valve solenoid, stuck one of the tubes in my mouth, put my finger over the end of the other and sucked :sucks:



I found that there was an air leak in the valve itself. I also checked it whilst it was electrically connected to the car with the Fiatecuscan software opening and closing the solenoid - still seemed leaky.

So for any skinflints like me here's how I fixed it:

I used a hacksaw to cut the crimped metal ring which holds the tube attachment to the solenoid body and separated the components.



I noticed that there was some rust inside which I cleaned out. I also cleaned the filters (one on the outside for air and one internally). I also lubricated the parts with PTFE spray. Then I reassembled and used a jubilee clip to clamp the metal ring back in place:



I re-attached all to the car except the blue hose to the actuator and noticed a much better vacuum when I put my finger over the end with car idling. Then with the hose in place I saw that the actuator now moved around considerably with varying revs.
Went for a drive and Hey Presto, no more bing bing bing, engine fault.

 

[Argonought]

Very interesting post

Although I've never heard of a leak in a VGT valve before it sounds like this might be a common failure for valves which have spent a fair time down under the headlamp in the wet :chin:

 

[robbie-rocket-pants]

I've noticed that if you run the engine for a few seconds and stop it then connect up to the FiatEcuScan software you can test the boost valve and see the turbo actuator rod moving (still with the engine off). It will move a number of times before the vacuum is finally depleted. So I recon this is a very good way to find out if you have a leak somewhere in the vacuum pipes.