Smokey AGU engine


Registered User
I have just fitted an AGU engine into my W T4 van. I had a donor car which I used for a few weeks. Now the engine is in the van it's smoking quite bad, not so nad after a run though in fact I'd say no smoke. Given that I still have a few things to wire up is there anything that could cause this other than a knackered Turbo (we checked it and there is no end float ) or rings/valveguide bits. The only thought I had is that the oil return pipe which goes intot he sump had to be modified and is possibly restricting flow into the sump. Would that back the oil pressure into the turbo and cause some oil loss into the turbo ? possibly worse when the engine is cold and oil thicker ?
It runs fine but lacks boost, I had an ECU upgrade and immobiliser delete so was looking for 10-12 psi but am only getting 4 psi max. The other thing I notice comparing it to my AGU engined A3 was that the boost gauge in the A3 reads 20 psi neg at tickover while the van is nearer 30 psi vac at tickover. I have no idea if this is realted to the smoke or maybe just cheap boost gauges being not calibrated. I guess next step is to swap gauges maybe.
Any thoughts on any of this would be welcome.