I think it is fair to say that the method of fuel management on older systems is very basic, when compared to what we see on modern common rail systems. Mechanical pumps that rely on spring tension & vacuum control, with no closed loop control. Compare that with "per cylinder" fuel trimming & precise fuel metering.
I don't think that it has been said that "they all have the same air fuel ratio" Bryan? The fact that there is a plentiful supply of air, doesn’t mean that the AFR is constant. You could still inject excessive amounts of fuel into a cylinder that has as much air as it wants.
I suppose we should consider the original question in this thread. Why are these EGR's & intakes clogging so badly?
Is it all down to a faulty EGR valve?
could it be influneced by any or all of the following....
Excessive oil consumption?
Long life service intervals?
Poor fuel quality?
Short journeys?
or anything else that would cause the system to generate excessive levels of soot.
The throttle plate discussion is interesting for sure, but what is causing the sticky residue to form in the valve? (as shown in the original post)
Is it just a deficiency seen in earlier systems, that has been partially overcome with the introduction of throttled intakes? Are we really seing an improvement in more modern arangements?
Your thought gents...
Cheers
Dave