Can anyone give me a quick run down of the 16v vaccum system❓❓

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My Name: SpudGun

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Posts: 20
Joined: Wed Jan 02, 2019 3:31 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4
Fuel Type: Diesel
Mileage: 116000
Trim Level: SX
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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Ok recently the car was down on power at the bottom end. Bit of smoke on acceleration. Have to keep the thing revving higher than normal to keep moving. Fuel economy down a good 10mpg.

From previous experience I know if there's problems with the vacuum system, the turbo doesn't fully actuated and you lose the bottom end grunt that makes diesels effortless to drive.

So I did the usual checks.

On start up, the turbo actuator moves up. Tongue / finger on the turbo vacuum hose confirms there's a bit of suction. But not what I'd expect.

With the engine off a blow down the hose I felt what I'd imagine is something unblocking, theres now more suck from the hose and a road test confirmed the turbos actuating again.

So I'm going to guess something needs a bit of a remove and clean or replace.

So where does the turbo vacuum hose go after it runs over the top of the engine and down the back somewhere? I know eventually it ends up at the vacuum pump, and the brakes seem to be happily working, so i'm happy the pump itself is working fine, but what else is in the system I should look at?
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My Name: C3CAR

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Posts: 2708
Joined: Wed May 04, 2011 10:01 am
Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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Been thanked: 103 times

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SpudGun wrote: Fri Nov 29, 2019 1:18 pm Ok recently the car was down on power at the bottom end. Bit of smoke on acceleration. Have to keep the thing revving higher than normal to keep moving. Fuel economy down a good 10mpg.

From previous experience I know if there's problems with the vacuum system, the turbo doesn't fully actuated and you lose the bottom end grunt that makes diesels effortless to drive.

So I did the usual checks.

On start up, the turbo actuator moves up. Tongue / finger on the turbo vacuum hose confirms there's a bit of suction. But not what I'd expect.

With the engine off a blow down the hose I felt what I'd imagine is something unblocking, theres now more suck from the hose and a road test confirmed the turbos actuating again.

So I'm going to guess something needs a bit of a remove and clean or replace.

So where does the turbo vacuum hose go after it runs over the top of the engine and down the back somewhere? I know eventually it ends up at the vacuum pump, and the brakes seem to be happily working, so i'm happy the pump itself is working fine, but what else is in the system I should look at?
It is quite complicated.

From the vacuum pump it feeds the brakes and a reservoir.
The reservoir feeds two vauccum valves, one for the EGR and the other is the turbo vacuum valve. Each valve then feeds the EGR or the Turbo vane actuator.

questions-about-a-diesel-powered-citroe ... t2479.html
vacuum system diagram Citroen C3
vacuum system diagram Citroen C3
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