'HDi's for Dummies' diagrams?

[old'uns]

here we go again......

MAP and Inlet temp sensors fitted, foam filter on the solenoid cleaned as per the video above.
still no boost although the inlet temp is now no longer -40 odd, now +40 ish
i wont overload your brains again





i couldn't get my hands down to the turbo actuator rod and have re-done the actuator test again on Lexia, all ticking away like little bombs.
cant feel any difference on boost pipes and looking at the info the max boost pressure was only around 1100mbar

am i right in thinking that the ECU is asking for the boost setting and the boost pressure should increase or track that asked for figure?
also similar for the turbo position setting and copy? setting asks for it and copy provides it?

in either case to my untrained brain the info looks as though neither are happening and boost pressure actually drops? a symptom of a naff turbo or boost leak?

[EDC5]

Yes. The values 'Turbo Position Setting' and 'Turbo Position Copy' should track each other very accurately.

I see this is still not the case from the pictures. It does seem to be changing between screenshots though, so something is moving. I'm not sure if there is an issue with the vacuum that actuated the turbo or the turbo itself.

I'm not sure if there's any way to tell what the issue is from those screenshots but it could be:

Turbo vacuum actuation diaphragm leaking
Turbo vac electrovalve faulty
Vac leak between electrovalve and turbo actuator
Turbo position sensor faulty

Is it possible to reach the turbo and move the rod by hand? if so, you could see if it is possible to get the full range of 'Turbo position copy' values (from 0-100) and then you could rule out the turbo position sensor itself; leaving only vacuum related issues as the possible cause.

[old'uns]

i can't seem to get to the turbo let alone feel what's what.
i'll assume the turbo position sensor is in the turbo area along with all the other gubbins i most likely need to take off?

i've now reached the point where my mechanical/technical knowledge drops off the cliff and the OH has started to look around at shiny things again.
most of the Mob Mechs around here are busy so thats another option closing even if i had to replace EGR/ vac pipes / turbo etc...not that i'd that without knowing 100% but i'm running out of ideas now as to where i go

[MikeT]

Are these readouts from a drive, or just engine running, parked up?
I had no reason to suspect the old MAF was problematic (ignore the errant -50c, it's a bug I'm sure), but I have to ask, why is the air intake temperature so high now? Even allowing for heatsoak, 40+c seems excessive.
We really need to know if the turbo actuator arm is moving or not as the pressure readings suggest the turbo's producing zero boost and the copy signal suggests the vane's aren't being closed either.

[Simple76]

Have to ask have you tried disconnecting MAF sensor and taking for a drive. Also do you get any pressure in turbo inlet pipe while raising rpm?.

[old'uns]

readings on the drive, not sure the laptop battery will last long enough TBH
MAF, MAP and inlet temp sensor are all new.
there is no way i can get my fat arms down there and i'm definitely NOT going underneath! as i said before the bit i can get in to i have no idea what i'm feeling without seeing a diagram or picture
what should the inlet temps be roughly if i get out for a drive?

not tried without the MAF
no movement felt on either of the inlet pipes, the pics above show a slight loss if anything when revved

[MikeT]

Sorry, I didn't realise it was so difficult to get an eye on the turbo on your engine. Any chance of a camera/phone recording a view?
I have to correct myself too and say there is some movement shown by the copy position data suggesting it's getting some vacuum at least. If it's getting properly regulated vacuum and the arm isn't retracting enough, then suspect sticking vanes or a holed actuator diaphragm.

[old'uns]

no problem, turbo is at back of engine, you can't even lie on engine and look down. too much in the way.
if i thought sticking vanes was a 75% chance or over, IF there was the room the Lump hammer would be out!

[EDC5]

Yes, the turbo is right at the back of the engine, under the EGR cooler. Impossible to reach from above due to the 30 degree cant on the engine itself.



That silver thing visible against the rusty exhaust manifold is the actuator diaphragm, better view here:



For some reason the ECU isn't recording the arm moving in and out in accordance with the vacuum requested from the solenoid valve.


It would be interesting to tee a vacuum gauge in the vac pipe between the solenoid valve and the turbo actuator to see what it reads.

[old'uns]

That silver thing visible against the rusty exhaust manifold is the actuator diaphragm, better view here:



For some reason the ECU isn't recording the arm moving in and out in accordance with the vacuum requested from the solenoid valve.


It would be interesting to tee a vacuum gauge in the vac pipe between the solenoid valve and the turbo actuator to see what it reads.

i can just feel the vac pipe in first pic, well the connection between the rubber / alloy
so the actuating rod is what looks like the Stanley screwdriver?
in situ that would be underneath so may be possible to get the car on stands and at least see if it moves

[EDC5]

so the actuating rod is what looks like the Stanley screwdriver?
in situ that would be underneath so may be possible to get the car on stands and at least see if it moves

Yes, that's the one, the rod with the yellow paint dots on it.

[Simple76]

You should be able to see the large rubber-pipe from the intercooler at front of engine coming into your inlet manifold expand as you rev vehicle . Simple to test to see if turbo is doing anything. Keep it simple it normally is.

[old'uns]

You should be able to see the large rubber-pipe from the intercooler at front of engine coming into your inlet manifold expand as you rev vehicle . Simple to test to see if turbo is doing anything. Keep it simple it normally is.

no movement at all on the pipe.
i did try it again after the test drive but still nothing.

i think i'm at the end of the simple things ie new sensors / plug n' play things, checking pipes etc, now into the realms of real money i reckon and decisions of heart over wallet

[MikeT]

If you can reach the arm (Stanley Screwdriver) with engine off, it should push in relatively easy, then fully extend again on it's own.
When the engine starts, the arm should get drawn in ~12mm though according to the copy sensor, it's moving less than half that.
If you can reach and also disconnect that vacuum pipe and with the engine idling, you should clearly detect a vacuum on the pipe side.

[old'uns]

thanks all...

tomorrow evening will probably be my last chance time wise to 'tinker', too late now even for a last minute impulse car purchase