was wondering though when i have the valve tronics disconneted dont have the misfire.
I have some understanding of this engine & Valvetronic did mess with my metal health when we first saw it.
I cannot tell you how Paralysing Valvetronic fault could ever solve a SINGLE CYLINDER Misfire. My knowledge is that Valvetronic alters the Inlet Valve Lift Equally across all cylinders on that bank.
If it were a failing Lifter I should see the problem come up even if its intermittent.
I'm not sure what you mean !
Intermittent or Permanent, how would you see a failed lifter. Of course, Pressure testing & Diagnostic elimination may guide you to suspect the lifter.
I'm not so sure how you could non intrusively test a Lifter. If you remove it then it may be obviously faulty or not.
My only thoughts are a pressure transducer on an Oil Gallery somewhere - Would be interesting to see that !
One last thought, With VT disconnected the Camshaft in is its lowest position providing maximum lift to the Valve(7 or 11mm I believe) Perhaps with VT working and less lift is required the Lifter fails to open the valve at all or only Partially.
And another last thought, Could a Worn Cam Lobe be masked by VT Disabled, that now leads me to ask if this has solid or hollow Camshafts. On a hollow Shaft the lobe can move ???
Look forward to hearing the fix on this.
Last edited by Iver on Tue Aug 11, 2020 7:11 pm, edited 1 time in total.
Thank you all for the input. Have now removed the camshaft, the eccentric shaft and the lifters, Dont see anything in particular that catches the eye. cam lobes etc measure out perfect in relation to each other, so does the lobes on the eccentric shaft, lifter are nice and tight no free play or looseness in them. Pressure testing the oil gallery could make an interesting one. need to check if there is any adapter that can plug in to the oil pressure sensor port.
One thing I noticed before removing the camshafts was we started the engine and it ran perfectly up to temperature of 90 deg C. and only after snap throttle a couple of times is when the misfire started.
Im at a complete loss of ideas at the moment. but am not the type to give up as now im really inrigued with this. Unfortunately my scope knowledge and experience is very beginner level so am at a handicap here.
Chad, don't give up as you have found the evidence you need.
You have identified the primary offending cylinder (there could be others) and you know that little air was drawn into the cylinder
You have also added that 90 Degrees seems to be the "transition" from no fault to fault. Could we research engine control at 90 degrees, is there a change of state with valve control etc?
If we concentrate on the the valve train, what could prevent both intake valves from opening or opening by the correct amount? What else could restrict the intake into our offending cylinder/cylinders?
I think at this point, whilst the lifters appear OK, replacing 4 for cylinder 2 could remove a variable we don't need.
Oil pressure is most certainly another concern as I believe we have fine control over the oil pump output (on demand function) This is food for thought only
I will dig into a recent case with a Mini using the N13 engine with a very similar symptom
lifter are nice and tight no free play or looseness in them.
Yes but in your hand they are not at 90 deg C. Nor are they Pressurised with Oil and a Cam Lobe Hammering away at them !! !!
One thing I noticed before removing the camshafts was we started the engine and it ran perfectly up to temperature of 90 deg C. and only after snap throttle a couple of times is when the misfire started.
tuve el mismo problema con un N13, al alcanzar la temperatura de trabajo la.compresion baja a 60psi y el motor fallo, tuve que desarmar el motor y poner anillos nuevos
If somebody discovered what the problem was please contact me at albert.solomon2003@gmail.com i am at the end of the tunnel here and i replaced everything and i don t know what to do anymore, the same cyl 3 misfire, sometimes running good and sometimes running in 3 cylinders. Thank you!