Dturbo not boosting.

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BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Dturbo not boosting.

Post by BMcN » 22 Apr 2003, 05:23

I have posted before about the lack of turbo kick. I hooked a boost gauge up to my car and it was struggling to read even 0.1bar (80MPH-90MPH with foot flat to the floor).
I jacked the car to find out what turbo i have, i have the Garret T2 version.
I beleive that the turbo is working as i can here a whistle at about 3kRPM and upwards with the window down. What can i try?
I need to test to see:
1st - If the turbo is creating the proper boost or if it is seized or broken.
2nd - To see if the wastegate is jammed open or broken.
3rd - To see if the boost is leaking somewhere.
How would i go about checking these things? In particular the wastegate.
Thanks

mgoodlad
Posts: 90
Joined: 19 Sep 2002, 22:17

Post by mgoodlad » 22 Apr 2003, 19:48

My 306 gradually lost turbo kick until it drove like a normally aspirated car. Turned out to be a hole in the pressure sensing pipe which goes from the middle front of the intercooler to the side of the fuel injection pump. Very easy fix (new bit of pipe and 2 jubilee clips). Another guy I heard of with the same car had the same problem after getting the glow plugs changed - it was the mechanic had pulled the same pipe off the intercooler for better access and hadn't put it back.
The pipe becomes pressurised when the turbo operates and pushes in a diaphram in the injection pump, telling it to pump in more fuel. When there is a hole in it the pressure escapes and the fuel pump doesn't know it needs to increase the fuelling.
Don't know if this is your problem - but easy to check for - where in the circuit did you connect the gauge?
Regards
Michael

BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Post by BMcN » 23 Apr 2003, 18:24

Yeah i am putting it up on the ramps tomorrow night, i will check all the piping then. How can i test the wastegate?
I connected the boost gauge to the pipe that delivers the boost to the fuel pump.
Thanks

mg46783
Posts: 104
Joined: 02 Sep 2002, 02:16

Post by mg46783 » 24 Apr 2003, 06:46

Hi..
With the engine running - go under the bonnet and with one hand revving the engine past the point the turbo would / should come in (make sure you pass that point )... have the other hand feeling for pressure in the air pipes too and from the air filter trunking - the piping to the turbo..you should feel them swell with pressure indicating all is well.. if not , check for fractures / leaks in all of the trunking... Check too that the turbo fan is actually turning, you can do this by simply taking the large bore pipe off the turbo and spin it with yiourfinger (engine OFF )... by sight you can then too see if the little fan impellers are in good condition and check too that the little centre nut is tight... they come loose sometimes meaning that the turbo shaft is spinning but the impellers arnt.
Check too that the small bore pipe on top of the turbo is in place and / or not split.
You can check the wastegate operation by hand or by running theengine, revving it and watching the levers to make sure they are their - and not seized.
Good Luck.. Let us know how you get on...
Mike

BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Post by BMcN » 25 Apr 2003, 23:39

I put it up on the ramps and got someone to rev the car and i cannot see the wastegate moving.... Whats next?
Do i try and unseize it or replace it or what?
Cheers, Bryan.

rossd
Posts: 420
Joined: 16 Mar 2001, 21:18

Post by rossd » 26 Apr 2003, 22:39

You wont see the wastegate moving whilst just reving the car, you need load on the engine for it to produce the boost to open the wastegate.

BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Post by BMcN » 27 Apr 2003, 04:27

Ok i took the arm off anf tapped the bit it clipped onto, it freed up and with the help of some WD40 it now now and moveable. The 'arm' of the artucator i can pull with my hand if i really really try, i can move it about 1cm. How else can i test the wastegate? Is it worth taking the actuator off?
I took the large air intake pipe off the turbo and i managed to spin the impeller, so it isnt seized.
There is a coating of wet oil on the inside of the air intake pipe (as far back as to the right of the intercooler), is this a problem?
What else can i do or try before i end up paying for a turbo specialist to look at it?
And if not how much is a recon/turbo exchange going to cost? Can you reccomend a good turboi specialist in SW scotland (i live very remotely).
Cheers

rossd
Posts: 420
Joined: 16 Mar 2001, 21:18

Post by rossd » 28 Apr 2003, 01:32

Oil in the pipes is ok as long as there is only a film of it, it comes from the crankcase ventilation between the air filter and turbo. If you can move the wastegate and the spring loaded actuator seems ok and also the impellers spin freely, the turbo is probably ok. Check for any leaks from any of the pressurised hoses, paying particular attention the the inlet manifold/intercooler seal. Make sure the pipe from the intercooler to the fuel pump isnt blocked or split, this will prevent boost build up AND sensing boost when you plumb in the gauge here. The book figure for boost is 0.7 bar at 2500 rpm and 1 bar at 3000, it should tail off after this as the wastegate opens and the turbo exceeds its optimum operating range. If this is all ok, remove the sensing pipe from the intercooler and blow through it. You should feel the diaphram inside move. Now try sucking, it should hold a vacuum.
Also make sure your boost gauge is ok!!
Ross

wheeler
Posts: 3761
Joined: 21 Sep 2002, 19:07
x 77

Post by wheeler » 30 Apr 2003, 06:17

is the vaccum pipe on the EGR valve clear,if there is a blockage/split in this pipe then it will cause the valve not to operate.

BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Post by BMcN » 30 Apr 2003, 20:02

It is a mechanically controlled turbo engine, its not the HDI engine mate. Do you mean the pipe from the turbo to the actuator? I am going to try taking this pipe off later tonight and putting a small compressor on it to see if it moves the actuator..... if not then i might replace the actuator and arm.

mg46783
Posts: 104
Joined: 02 Sep 2002, 02:16

Post by mg46783 » 22 May 2003, 05:13

I have only just got my pc back from repair... How you getting on with this one???
Mike

BMcN
Posts: 27
Joined: 03 Apr 2003, 16:41

Post by BMcN » 23 May 2003, 04:44

Well Mike everyone has ran out of idea's by the looks of it so I am resorting to changing the turbo. I bought one second hand for £110 but it seems like the wrong one.... however i managed to pick one up off a 406 1.9 TD for free and i think its the same.
I am going to try changing the actuator tomorrow night, if that doesn't work then I'll change the whole turbo unit.
My car does not have an EGR by the way.
The impellers are still spinning.
Can someone set me straight on this point please..... From what I know have gathered that when the turbo is sitting idle, the wastegate is closed and the actuator arm is sitting as 'short' as it can be. Now when the boost builds up the arm lenghthens (sp?) opening the wastegate. So if the actuator was indeed broke, or the pipe leading to it was split, then shouldnt the turbo be creating 'unlimited' boost. In theory of course.

Dave Burns
Posts: 1916
Joined: 14 May 2001, 05:30
x 2

Post by Dave Burns » 24 May 2003, 00:48

Does the 406 have the intercooler above the engine like the 306 or is it in front of the rad like the xantia.
I ask this because the turbo outlet is at a different angle on the xantia to that of the 306, ZX etc. this means a turbo from a front intercooler car like xantia, can't be piped up to an above engine intercooler using the standard pipework, if at all.
The normal state for the wastegate is closed under spring pressure.
Increasing boost pressure overcomes this preset spring pressure and opens the wastegate to keep the boost at that level and prevent it building up any higher.
If the actuator was broken its unlikely that there will be any boost pressure developed, unless it was siezed in the closed position.
If the pipe to the actuator is split or leaking, the waste gate will still operate providing sufficient boost pressure is attained.
If completely disconnected (and left open) from the actuator then either maximum boost will not be reached, or if the turbo output is more than the engine and the leak (disconnected pipe) can consume, then overboost and possible shaft overspeed may be the result.
Dave

mbunting
Posts: 712
Joined: 21 Dec 2001, 16:19

Post by mbunting » 24 May 2003, 13:08

Isn't that just fabulous engineering...
We'll use the same engine, gearbox, hell, probably the same intercooler but horizontal instead of vertical, but, hmm... I think it would be easier to change the design of the turbo than put some more curves into the pipes !
Wonderful, no wonder we had to help them out in ww2 !!!
Just like the Germans, I had to wait four weeks for a set of rear radius arm bolts from Germany, all the time MB were paying for me to drive a top of the range Avensis !