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Discussion Starter #1
Hi all,

I have a 307 SW HDI 110 on an '03. Around town the car is fine but recently on motorway/A road journeys the turbo will cut out and will not return for the remainder of the journey.

All planet says is 'Turbo pressure measured too low'. I have replaced the turbo control solenoid which has helped but I am now left with a turbo that cuts out at very specifics points. When I am accelerating and then slow down suddenly that's when it cuts out.

Such as, going up hill and then coming off the gas at the top of the hill the turbo cuts out.
Or, accelerating to overtake and then slowing down turbo cuts out.

There are no other symptoms and if I stop and turn the engine off for a minute and then restart the turbo is back.

The car has no DPF. This was removed physically and programmed out about 5K ago so don't think it's related to this. Also no CAT.

Any help would be much appreciated.

Pete
 

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I come from old school turbos where the boost is physically controlled by an actuator (a valve with a spring, if you like) this operates a wastegate that diverts the exhaust gases away from the turbo once full boost has been reached, to prevent over boosting.
The only way you would lose boost is if:

1) the bearings are shot and it starts sticking - Here the turbo doesnt spool up when you boot it, nothing, nothing, a bit, nothing, then suddenly normal boost (and will possibly make some horrible noises here and there).

2) The wastegate gets stuck open thus the turbo doesnt spool up at all (you never get any boost).

3) There is a leak somewhere in teh system and the boost is pissing out under the bonnet. (consistently low boost not intermittant like yours)

4) Dump valve stays stuck open after gear change so it wont boost properly afterwards.

I assume the boost is electronically controlled these days. So If its intermittant I would guess that the device which controls the exhaust gas flow to the turbo is playing up (electronic actuator?). Perhaps a dodgy boost pressure sensor which is sending the ECU incorrect readings which is then affecting the boost pressure being allowed.
That would be my guess but could be wrong. I doubt these engines have a dump valve of any kind but if they do that could be at fault also.

May help but possibly not.
 

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Discussion Starter #3
Damian, thanks for the suggestions.

Reading your post reminded me that the boost will come back on at 3k revs but only for literally a second and then it's gone again.

The 110's have electronic turbo control apparently, along with numerous boost vacuum pipes but I am no turbo expert hence why i'm struggling to work out the cause.

I understand wastegates and had wondered whether for some reason it was getting stuck open? but I'm not sure what would cause it?

As mentioned it happens when I accelerate and then come completely off the gas. However, if I accelerate and then slow down very gradually the turbo boost remains available???

Cheers
 

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Cant see it being a leak in the vac pipes as that would be more constant rather than intermittant.
My guess is either a sticking wastegate or boost pressure sensor causing it to be held open.
 

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Discussion Starter #5
Is the boost pressure sensor also referred to as the MAP sensor?

I'll try and get a look at the turbo if I can but problem is it's hidden behind the engine.

I've also read that there is an actuator that opens and closes the wastegate but I'm not sure where it is or if it is controlled electronically or via vacuum.

Any ideas anyone?

Cheers
 

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MAP sensor is what it was called on the Celica GT4. Although it wasnt used to control the boost it was used by the ECU to control fueling. Something similar must be used if boost pressure is electronically controlled on the peugeot. It could be the actuator itself getting stuck as well.

Yes they never put these things in easy to get to places :nono:
 

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Discussion Starter #7
The vacuum system is the only thing that gives any amount of grief on this engine. Thats where id be starting.

Sent from my GT-S5690
Thanks David I shall give the vacuum system another look over.

It really is odd because I can drive around town all year long no problems but once on a long journey its only a matter of time before the turbo cuts out and always when coming off throttle???

Pete
 

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Discussion Starter #8
MAP sensor is what it was called on the Celica GT4. Although it wasnt used to control the boost it was used by the ECU to control fueling. Something similar must be used if boost pressure is electronically controlled on the peugeot. It could be the actuator itself getting stuck as well.

Yes they never put these things in easy to get to places :nono:

Yes several things hidden on these, EGR, Turbo, Clutch master all behind the engine :mad:

I shall have a look back there via the passenger wheel arch first to see what I can see. After that I might need a 4 poster and have a look from underneath.

Cheers
 

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boost is controlled by the vacuum it works in the opposite way to proper turbos and needs vacuum to CLOSE the wastegate no vac no boost a leak in the vac circuit will affect other parts ie egr vac leak can affect boost etc.

You need good stable vac readings both at idle and when revved
 

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Discussion Starter #10
Hi reliable406. Your suggestion of EGR has prompted me to hook planet up again as it's been a few weeks since I had it hooked up for this fault.

I am still getting 'Turbo Pressure Measured too Low' P0246.

I am also now getting 'EGR Air Flow Higher than Recommended' P0402.

As ever the skill is in the interpretation which is what I am struggling with. I shall try and post up the findings along with some live running data.

Any help or suggestions greatly received.

Cheers
Pete
 

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Discussion Starter #12
Hi all, here is an update on this problem that I am still struggling with.

I have just completed a 500 mile round trip. Turbo cut out 3 times on the way but not at all on the way back. On the way back I deliberately did not put the engine under any strain and did not exceed 70 so it seems that when the engine is under load or revved above about 2500 for any length of time this is when the turbo cuts out.

From the live running data that I have posted up it shows that the car is not producing any increase in measured turbo pressure until around 2k revs. Does anyone know if this is how it should be?

It is looking more likely that there is a leak somewhere and I shall be going over the whole system soon to try and find any leaks.

In light of the new EGR fault I am also looking to block the EGR by doing as David suggests and seating it with a vacuum gauge and then I'll block the pipe with a grub screw and see if this makes any improvement.

Cheers
 
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