S80: Engine Turbo Boost Pressure Solenoid 31293964

[TheBeast]

Thanks for your input Thassos.

Originally Posted by Thassos

Morning,, i had missed your drawing in post #5 (so much for speed reading!), would the pierburg part be item 12? and the vaccum actuator the round component below the turbo? with no number?

Correct.
Annoyingly, I believe with this car, I'd have to buy a whole new turbo+vacuum actuator if a part turns out to be faulty. But fingers crossed the fault lies elswhere.

To be fair, the car drives fine and seems to have enough power, so is very drivable.
Also, she just passed the MOT so emission wise (all this could be EGR related too according VIDA) all seems well...

Originally Posted by Thassos

Some questions & things to try..

A) you mention applying 12v (would suggest using a DVM to probe the 2 wires going to the pierburg 'solenoid' to see what polarity they are before applying 12v in same polarity. If you blow on the port when 12v applied, does it pass thru or close flow of air?

Tried to see if there is a difference between power on and off, but didn't feel any difference. This is just me blowing/sucking on an attached hose though. Will try it with a vacuum pump attached and see how that goes.

For polarity, I used a Youtube video of somebody showing a diagram of one, so hope that was a comparable item.

I will see if I can confirm the polarity the way you suggest.

Originally Posted by Thassos

B) Well worth getting a cheap chinese version of a mityvac, or maybe use a large syringe with tube and attach to the capsule to see if you can make the turbo actuator move with vaccum applied, sometimes you can freely move the arm or linkage with no tube attached, or get an idea of what resistance there is to moving the linkage incase its something internal to the turbo.

Great minds and all that... Just ordered a very cheap one this morning that should be sufficient for my purposes. I have no need for a fancy one, as I won't get enough use out of it.

Originally Posted by Thassos

C) You might also use the 'mityvac' attached in place of the capsule to see if any vaccum is getting applied via the 'solenoid' similarly with engine running, (again just ideas here..) Also see if the tubing run back from the capsule will hold a vaccum - incase of a split or poor / missing tube connection.

Will do.

Originally Posted by Thassos

Usually on pwm type connections one side is permanently (chassis, or +12v feed) and the other is switched on-off on a regular time loop that is giving the %age from fully open to fully closed. No idea if this applies here but with 2 wires to something there are only a limited number of ways it can work ! the signal will be coming from the ECU from one or both sides, might also be worth using a dvm to trace the wiring back to the ecu plug (just use a small bit of small guage wire to 'probe' the connector without pushing something oversize in it that might cause damage,..) incase its a broken electrical connection (prob less likely).

If you have a DVM, but not all will have this function, you need one that can show frequency or something like (may have PWM in its setting), you could attach this across the actuator (ie with it all plugged in), only easy way is with sharp probes, a bit of info below might be useful

https://www.fluke.com/en-gb/learn/bl...ure-duty-cycle

Anything to do with electrics is witchcraft to me, but I'll have a good go at it! How you do switch on a multimeter..?!?

Thanks for the link. I'll have a look.

Originally Posted by Thassos

You mention your engine is a T3? so is it a single turbo not twin? some info from wiki, below (cant believe how many versions there have been...)

https://en.wikipedia.org/wiki/Volvo_D5_engine

Yeah, madness how many versions there are… I believe it is a single turbo, yes. But currently have the heat shield still sitting above the turbo so con't confirm, but the diagram would imply so.

Thanks for your pointers.