Having looked at all the data in the previous pages [Van Data] [Van Data 4-Gas] the question
arises; what now ?
That's where I need your help :)
It's clear there is something wrong with the Van and/or it's
engine, but the data is in no way (at least not to me) conclusive
as to what is wrong.
I've talked to a number of people about this, but haven't come to
a conclusion that would explain the sometimes conflicting data
readings.
If we look at the power over time graph
you can see the problem already starting in 3rd gear, but really
showing it's ugly head in 4th.
During normal driving this is not apparent, but once you push to
the 5000rpm limit in 4th it feels (and sounds) like it's
misfiring all over the place.
The power vs
rpm graph shows that the problem arises in 4th gear (as well
during the 2nd as 3rd run), but not (near as much) in 3rd gear.
This would indicate that it's not rpm related but either speed or
time related.
If not rpm related this rules out a lot of the more common possible causes.
The power vs
speed graph shows that the problem does arise at about the
same speed.
The power vs time
graph shows that the problem is not really time related.
But what problem arises at a certain speed but not at a certain rpm ?
And then there are the exhaust
gasses.
Looking at the data it shows that the HC, CO and O2 values are
too high.
Strangely enough the test run where it all went 'south', in 4th
gear, is the one showing the best values for HC, CO and O2.
As the CO value is too high this would indicate a mixture that is too rich. But that would not explain the O2 and HC; apparently there was enough fuel and oxygen left to burn. Which might indicate a misfire caused by something unrelated to mixture but more to ignition.
As the RR run in 4th gear indicated something seriously (as in mayor, not really serious as in may kill the engine) wrong, I decided to have that sorted first and then see what the values would be. As it is the values do not clearly point out a certain failure that could be causing the problem.
Below I'll post the suggestions made and 'discuss' the
possibility of this being of influence.
I'll also list the actual problem if we ever find a specific
cause for it.
Obviously part of these discussions may also take place on the
various Mini-lists, so you might want to join the discussion
there.
Feel free to email
me on the subject though.
