Quote:
Originally Posted by ZetaTre
Max absolute manifold pressure I've seen is right below 3bar. No vacuum on diesels (unless you're idling during regen).
Boost isn't really that meaningful of a variable to assess engine load in a diesel since it generally throttle fuel, not air. Better parameters are rail pressure maybe coupled with EGT (although with the emission systems EGT becomes a bit more tricky).
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I have an issue with my 2011 X5 35d.
It keeps going into limp mode.
I bought it wholesale from a mechanic when he and the customer couldn't reconcile.
The issue is it goes into limp mode and gives codes 4530, 3FF0, 4865.
It builds plenty of power but goes into limp mode at about 35mph.
The car has been smoke tested twice and has alot of parts thrown at it. ie. new MAF,MAP, fuel rail and pump, and I replaced all the vacuum lines and pressure converters and swiched the EL valve under the pressure converters.
I did a swirl flap delete and replaced all the intake manifold gaskets and removed the valve cover and replaced the valve cover gasket. It had CBU in the Intake and valve cover but the valves themselves looked fine.
Your quote about the car targeting fuel and trottle positon instead of boost has me curious.
When I put my torque app on and look at the PIDs for BP and BP Commanded it says the following.
It has a BP-A and BP-B which I assume means the large and small tuirbo.
BP-A never moves from 4.6psi but my BP-A commanded goes up and down with as I give it throttle.
BP-B reads -1.2psi and BP-B commanded reads -1.2
Now the interesting thing is my exhaust Temp reads 31degrees F and never changes.
So following your logic since the EGT isn't being read the car thinks that there is no boost but in reality it is building boost which could make it throw the 4530.
Does this make sense?