Hi

Think of this senerio on a rolling road,

Just want to put this out there to see what people's opinions are,

The senerio!

Car is on rolling road,

The waste gate on the turbo is sticking fully open,

You rev the engine up under load on the rolling road,

Engine will not rev to its maximum and only about halfway of its limit,



Will the wate gate sticking open be the cause of the engine not revving up fully to its max RPM? yes or no

All that an open wastegate would do is massively reduce boost made, should half your available rpm surely?

Yes thats what im thinking if the turbo cant produce enough boost pressure and the fuel can't rise with the boost it surely will reduce the the maximum RPM that the engine can reach.

Shouldn't restrict engine speed - unless the sticking wastegate has been recorded as a fault by the ECU, in which case the car might possibly go into limp home mode?

Its not controlled by ecu its carb'd and fuel pressure is governed by fuel pressure regulator.

Even so, I would just expect less power. As long as the engine is getting atmospheric pressure (per any naturally aspirated engine) the engine should be free to rev. I wouldn't have thought a sticking waste gate should restrict engine speed. Sounds more fueling / timing related to me.

Its strange because it is not a permant problem it happened whilst on the rolling road 3 or 4 times in a row then it went back to normal and then drove 45 miles home and has never returned, however it has not returned as I have had the turbo off and sorted the waste gate, so thats why Im assuming it is the waste gate.

the compression will be all wrong along with the timing and fuel if its not making boost. its basically like restricting the inlet on a na engine then expecting it to rev freely, never gonna happen.

As above....

OK - let me re-phrase my comments!!
Only if your running at full load WOT conditions would I expect the engine not to make full rev's (but that's just because you're not getting the same boost pressure to achieve the same performance), but under part load conditions the engine should be able to rev to fuel cut off.

I doubt you'd have been able to load the car enough under "normal" driving conditions to notice this problem on the road - unless you tow with your kit car or live on a really big hill!

If you still think differently, well i've learnt something new! lol