What Is This Part For?

[Bobley]

It's a throttle of shorts. The clues in the name - differential pressure. It's a way of promoting the EGR into the inlet of the engine if the exhaust pressure alone isn't sufficient. It can also be used to strangle the engine when you turn off the ignition which causes it to come to a very smooth halt rather than a great big shudder.

[zakmuh]

Thanks for your reply.

Yeah, it's a throttle flap kinda thing, shown below, but I spend most of yesterday trying to find missing hose connection for it, nothing is there. All the vacuum hoses are connecting something. I tried online as well and there is nothing I can find related to this part.

If it's THE throttle flap, then it should be in closed position when engine is off then it opens according the acceleration. As nothing wrong with my engine or driving and acceleration working all fine, I think I should leave it as it is?

[Bobley]

It is a throttle of sorts but it isn't involved in controlling the power output of the engine. In normal operation it would only close in order to pull exhaust gas in. The vacuum hose which activates it would be clumped together with all the hoses running from the brake vacuum pump to the servo and also to the wastegate/VCT diaphragm. It could be a tiny tee piece and it looks like you engine has had it's EGR system disabled so whoever did it probably threw the control solenoid away too so all which remains may be a pair of wires and plug coiled up somewhere?

[anonymous-user]

Bobley said:

It is a throttle of sorts but it isn't involved in controlling the power output of the engine. In normal operation it would only close in order to pull exhaust gas in. The vacuum hose which activates it would be clumped together with all the hoses running from the brake vacuum pump to the servo and also to the wastegate/VCT diaphragm. It could be a tiny tee piece and it looks like you engine has had it's EGR system disabled so whoever did it probably threw the control solenoid away too so all which remains may be a pair of wires and plug coiled up somewhere?

^^^ This. Any vaguely modern diesel has a throttle flap to create an inlet vacuum to control EGR flow, and also to shut off the air supply completely for a smoother shutdown or to prevent runaway if things go st shaped.

[zakmuh]

Bobley said:

It is a throttle of sorts but it isn't involved in controlling the power output of the engine. In normal operation it would only close in order to pull exhaust gas in. The vacuum hose which activates it would be clumped together with all the hoses running from the brake vacuum pump to the servo and also to the wastegate/VCT diaphragm. It could be a tiny tee piece and it looks like you engine has had it's EGR system disabled so whoever did it probably threw the control solenoid away too so all which remains may be a pair of wires and plug coiled up somewhere?

I should agree with you Bob cos, the inlet manifold is les clogged compared to the EGR unit to the valve. It must be disabled.

In the pic below, yellow arrowed pipe is closed with a metal cap at the back of the engine. I think that's the one supposed to be connected to the unit? The other pipe is connected to EGR...