Home Register Manuals 164 Forum Interactive Library
Login

 
 

FIXED THE ERROR MOVEMENT PISTON PROBLEM VISCOMATIC!

For the technical things.

FIXED THE ERROR MOVEMENT PISTON PROBLEM VISCOMATIC!

Postby alfa164superwebmaster » Thu May 03, 2018 8:20 pm

Dear all,

As you could have read in my previous posts, I was struggling with the dreaded 'Error Piston Movement' problem after the rebuild of my Q4. Also with my previous Q4 i was facing this problem.

I tried to bleed the system with the Alfa Tester MA12A module numerous times, without success.
Als the Course Piston Parameter (piston movement) stayed at 0%, no matter what I tried.

So I decided to try to actuate the solenoid by hand, to see if the piston would move when controlled manually.
To do this, I purchased a PWM controller from Conrad.
The type I used was a Kemo Power Control M171 DC 5A

I connected the PWM controller to the solenoid on the viscomatic unit, and a 12V 2.5 A power supply from my wifi modem ;-)
When running the engine, I turned up the potentionmeter of the PWM controller.

After one or two full power settings, I hear a slight 'clunk' at the diff and I got 100% piston movement on the Alfa Tester!!
Disconnected the PWM controller and reconnected the Viscomatic ECU to the solenoid.

Everything now works like a dream.
So it seems the Viscomatic piston got stuck from standing still (car stood for 4 years).

The PWM controller is very handy for debugging the Viscomatic, so I hope this helps the Q4 drivers out there.
Pictures are attached.

Cheers!

pwm1.jpg
Viscomatic PWM controller 1


pwm2.jpg
Viscomatic PWM controller 2


pwm3.jpg
Viscomatic PWM controller 3
alfa164superwebmaster
Q4 owner
 
Posts: 52
Joined: Wed Sep 30, 2009 2:29 pm
Country: Netherlands (nl)

Re: FIXED THE ERROR MOVEMENT PISTON PROBLEM VISCOMATIC!

Postby Alfan » Thu May 03, 2018 10:10 pm

Awesome!!!!!!!!!!

That is great work and thanks for sharing the info :D
1994 Alfa Romeo 164 Q4 Proteo Rosso 550.000km
1989 Lancia Thema 8.32 Verde Indy 260.000km
2001 Alfa Romeo Spider 3.0 24V Blue Lightning 50.000km
2015 Alfa Romeo 4C Rosso Competizione 75.000km
User avatar
Alfan
Q4 owner
 
Posts: 1072
Joined: Thu Oct 22, 2009 8:20 pm
Location: Denmark
Country: Denmark (dk)

Re: FIXED THE ERROR MOVEMENT PISTON PROBLEM VISCOMATIC!

Postby AlfaWhiz » Sat May 05, 2018 6:37 am

Great result! :D

Very glad to hear that you've fixed it, well thought out method. Good to have this trick on the sleeve as many of us had or still have this issue.
User avatar
AlfaWhiz
 
Posts: 371
Joined: Thu Feb 06, 2014 1:15 pm
Country: Poland (pl)

Re: FIXED THE ERROR MOVEMENT PISTON PROBLEM VISCOMATIC!

Postby 164 TD » Sat May 05, 2018 11:46 am

Image

Still wondering what part of the gearbox the actual piston is. You can see the viscomatic coupling plates very clearly, but the piston that "squeezes" the viscomatic plates and the piston that actually mechanically connects the inputshaft to the viscomatic are hard to determine.
TD en Q4 owner

Image
User avatar
164 TD
Q4 owner
 
Posts: 1190
Joined: Fri May 29, 2009 3:13 pm
Location: Honselersdijk
Country: Netherlands (nl)


Return to Technical

Who is online

Users browsing this forum: No registered users and 2 guests