Food for thought - Worcester 30CDI

[vern]

That's a good point ... MI says fan pressure should read negative -3.9 or greater how does -3.9 work with the tolerances you mention?

Correct and it takes a really fouled cell to get readings this low, only one I had backed to a dusty farmers field/ track it was all inside the combustion chamber,.....minus 4 so I stripped it and flushed with water back upto 5 ish