More likely while they were able to modify the engine operation to reduce the NOx during testing the reduction wasn't sustainable without some form of damage. Caterpillar tried to avoid some of the emissions reductions strategies and what I heard the 2007 and later on road engines had all sorts of problems. 2009 was the last year for any Cat on road engines. They basically left the business. Cat Branded trucks have someone else's engines. I believe Internationals. The ultimate fix may be for them to somehow add the equipment to use the Diesel Exhaust fluid technology. 

Dennis
 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of David Bjorkman
Sent: Friday, March 18, 2016 5:15 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Model year question on 90/91 Vanagons

 What blows my mind is that the emission controls were there and workable.  It's just that they only got turned on when the vehicle was being tested.  All for a few more MPG.

On 03/18/16, SDF ( aka ;jim lahey' - Scott ) wrote:

So VW was cheating the system way back them even ?
! lol.

Their modern diesel emissions cheating perhaps didn't even seem like that big a deal to VW perhaps.
That's flat illegal ....a manufacturer telling the gov a vehicle is one thing, when it's really not.
CARB and other agencies take a very dim view of such shenanigans.

>