Interesting you say no response to WD40. I have started & run a 602 for several minutes on WD40, I dont suggest that any one do it but I know it works. If you spray it into the inlet, even the air cleaner, & not just a quick spray, it should run the motor while you continue to spray it.
Maybe badly blocked inlet manifold from EGR?
If the exhaust was blocked, you wouldnt expect much spin on the turbo.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving