Technical Vacuum

[Mikes multipla]

Hello guy my bug is giving me **** again the vacuum playing up with all the vacuum pipes in place the car battles to idle if I pull 1 pipe off is fine but without the vacuum the plunger on the turbo for the waste won't operate diagnostic test come out with error code p0236

 

[widemouthfrog]

Have you tried using the forum search (in the green bar near the top of the page) with P0236 as the search term? It doesn't need to be a search specific to the Multipla section. You'll get loads of results.

 

[portland_bill]

A diesel engine does not create vacuum like a petrol engine. Vacuum for the brakes is created by a vacuum pump, usually driven from the camshaft.
A turbodiesel will create pressure in its intake system after the turbo. All its monitoring is based on pressures. Presumably it is a pressure pipe you are removing, not a vacuum pipe.

There are lots of pipes.
Please be specific with which one you are removing, connects from where to where? Pics may help.
Give as much detail of what the problem is so that others can help diagnose.

 

[Mikes multipla]

On the manifold just after where the pipe from the intercooler connects on there is a little round black thing with a single rubber pipe on it If I pull it off car idles ok if I put it on cars idle drops to almost cut out its not even that pipe I can pull the pipe off the turbo boost pressure valve same thing happens turbo boost pressure valve is the valve that sits on the side of the air it's got a red pipe on that goes to the turbo I cannot drive the car either way if all the pipes are intake I got no acceleration if I ride with a pipe disconnected the turbo won't function properly I did order a turbo boost pressure valve

 

[glowplug]

Why not post a picture as has already been mentioned. There are lots of pipes and it would make helping you a bit easier.

Also noticed that you are in South Africa, gee didn't know they sold the Multipla there. I can imagine they make for a good Minibus Taxi over there as a cut down version of the Hiace, made for 6 but can easily fit 20 on the way to Soweto. (other South African's will understand the joke)

 

[Mikes multipla]

Hi yes im in south Africa and to be honest the multipla it ugly bug ar not very popular there must be like 15 of the ugly bugs in south africa parts I can only get from the agents not even scrap yards can help no aftermark parts available I can import but at the end of the day the price I might aswell just order from agents and in Sa the agents rip u off

 

[Mikes multipla]

The first picture is the black round thing up on the manifold and 2ng is the part I suspect is playing up

 

[glowplug]

It's dark here now so I can't check but does that not provide the vacuum to the turbo wastegate ?, Could be it is providing constant vacuum so the wastegate is fully open and you are getting no boost and worse no back pressure ?

 

[portland_bill]

PO236 relates to turbo boost pressure too high.

Could be pressure sensor faulty, or could be pressure too high, indicating a seized wastegate. http://engine-codes.com/p0236.html

 

[Mikes multipla]

That exactly what's happening once the waste gate is fully open car idles ****ty and no acceleration when i pull 1 of the pipes off waste gate springs back to its normal position car idles ok I can even ride it like that with the pipe off but don't want to scard of popping the engine

 

[widemouthfrog]

What you're calling the 'waste gate' - is that the round thing mounted at an angle on the turbo that has the small diameter tube running to it?

The part you've shown photos of (in post #6 ) is the turbo VGT actuator solenoid.

 

[Mikes multipla]

Yes with a red pipe to it the thing that operates the waste gate sorry it's called the plunger rite anyway the rod that moves the waste gate that moves with the pipe on when I take the pipe off it jumps back to the normal position

 

[widemouthfrog]

OK. We'll, it's NOT a waste gate; neither is the part of the turbo that it connects to. It is the actuator for the variable geometry vanes inside the turbo. The small pipe to it (de)pressurises the chamber inside the round body of the actuator, pulling a membrane inside it. The small rod that sticks out of the top of the actuator is connected to the membrane, so it moves when the pressure in the chamber changes, pulling the vanes inside the turbo which is what varies the turbo geometry.

With all of the pipes connected up, get someone to rev the engine from tickover through to about 3,000rpm. Does the above rod move? Have you tried bypassing the actuator solenoid, connecting the two pipes that run to it directly together?

This isn't the same turbo as fitted to the Multipla, but it's good because it clearly shows what should be moving, and from where, to where. Fast forward to about 6:00 minutes:



and

 

[Mikes multipla]

The picture on left it the round black thing which sits on the manifold just after where the intercooler pipe connects the pipe goes from the black round thing to somewhere under the manifold the 2nd picture is the part gets to pipes on on of the pipes is the red pipettes goes to the turbo

 

[Mikes multipla]

On start up that rod will move all the way until it can't go anymore and that is when the car starts to idles rough just about to cut out when I pull a pipe off that rod will go back to the same position as it was before start up and then the car will idle normal again

 

[widemouthfrog]

Sounds to me as though the actuator solenoid (the thing in your photo with the white top and 2 pipe stubs sprouting out of it) is stuck open. That's allowing vacuum to the actuator at tickover, so the actuator rod moves straight away rather than when the revs rise.

Take the solenoid off the car. Put your lips around one of the pipe stubs and blow. Does air come out of the other stub, or is it not possible to blow 'through' it??

 

[Mikes multipla]

The above rod moves all theory just on idle after that sounds like the car wants to die until I pull a pipe of then it idles ok but the actuator will not operate without that pipe

 

[Mikes multipla]

I van blow straight through the 1 end

 

[Mikes multipla]

I have ordered 1 just waiting till it arrive and will put it in then c what happens will let u no but thanks for all your people help has really help me out

 

[Mikes multipla]

Hi I got the actuator solenoid put it on went for a drive went OK for like ten minutes and up pops the engine light contact garage the rod on the actuator move if I such on the pipe but I didn't see it move when I started up reved it up till around 3000 rpm didn't move so I guess it might be map sensor is there any way of testing them out with a multimeter or not