Turbo diesel - wastegate vacuum failure - what happens?
Discussion
Quick question on TURBO DIESEL wastegates: I know the wastegate opens and closes to control boost. I know that the vacuum line goes to the control solenoid which opens or closes to put vacuum (or not) on the actuator which then opens and closes the wastegate.
Question is, what happens if the vacuum fails for some reason? (e.g. if the vacuum pump fails, or a hose came loose, or a hose split or leaked)
Obviously the solenoid position will have no effect and so the wastegate will do whatever comes naturally. But does it normally clamp shut? (potential overboost?) Or does it normally clamp open? (Lack of boost so low engine power?) Or does it do something else? (Shut and then ping open above the spring pressure?)
Help please.
Question is, what happens if the vacuum fails for some reason? (e.g. if the vacuum pump fails, or a hose came loose, or a hose split or leaked)
Obviously the solenoid position will have no effect and so the wastegate will do whatever comes naturally. But does it normally clamp shut? (potential overboost?) Or does it normally clamp open? (Lack of boost so low engine power?) Or does it do something else? (Shut and then ping open above the spring pressure?)
Help please.
I know on a petrol car if I disconnect the control wires from the wastegate solenoid then it generates very little boost, can't remember why though.
It's really what happens with no vacuum on a diesel I need to know about. What would happen if I pulled the pipe off the solenoid input for example? (i.e. the vacuum pump side).
Would that cause fuel cut, or would it leave the W/G open and hence virtually no boost??
It's really what happens with no vacuum on a diesel I need to know about. What would happen if I pulled the pipe off the solenoid input for example? (i.e. the vacuum pump side).
Would that cause fuel cut, or would it leave the W/G open and hence virtually no boost??
mrmr96 said:
Quick question on TURBO DIESEL wastegates: I know the wastegate opens and closes to control boost. I know that the vacuum line goes to the control solenoid which opens or closes to put vacuum (or not) on the actuator which then opens and closes the wastegate.
Question is, what happens if the vacuum fails for some reason? (e.g. if the vacuum pump fails, or a hose came loose, or a hose split or leaked)
Obviously the solenoid position will have no effect and so the wastegate will do whatever comes naturally. But does it normally clamp shut? (potential overboost?) Or does it normally clamp open? (Lack of boost so low engine power?) Or does it do something else? (Shut and then ping open above the spring pressure?)
Help please.
With no vacuum, you will have no boost. If indeed the w/g ( usually VNT turbos ) is vacuum controlled.Question is, what happens if the vacuum fails for some reason? (e.g. if the vacuum pump fails, or a hose came loose, or a hose split or leaked)
Obviously the solenoid position will have no effect and so the wastegate will do whatever comes naturally. But does it normally clamp shut? (potential overboost?) Or does it normally clamp open? (Lack of boost so low engine power?) Or does it do something else? (Shut and then ping open above the spring pressure?)
Help please.
Failsafe really. Worst case scenario, no boost.
stevieturbo said:
With no vacuum, you will have no boost. If indeed the w/g ( usually VNT turbos ) is vacuum controlled.
Failsafe really. Worst case scenario, no boost.
Ok, cheers stevie. With a name like that you probably have trusty advice!Failsafe really. Worst case scenario, no boost.
I thought it would probably 'fail safe' and driving the car that feels like what's happening. I know one of the lines has minor damage so I'll get it swapped for a new one and see if that cures it.
Cheers.
Mr2Mike said:
Does the 330D even have a wastegate? I thought they used variable geometry turbos?
I guess w/g can also be perceived as the actuator that controls the vanes. Rather than an actual mechanical wastegate orifice.But on that note....I know some, or most of the BMW 2.0 diesels have an electronically controlled VNT and no pneumatics involved at the turbocharger itself.
stevieturbo said:
I guess w/g can also be perceived as the actuator that controls the vanes. Rather than an actual mechanical wastegate orifice.
But on that note....I know some, or most of the BMW 2.0 diesels have an electronically controlled VNT and no pneumatics involved at the turbocharger itself.
Indeed. Same on the 330d's, some have electric and some are vacuum actuated.But on that note....I know some, or most of the BMW 2.0 diesels have an electronically controlled VNT and no pneumatics involved at the turbocharger itself.
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