excessive smoke @ idle

[mako224]

Hi all ... new to the forum and have been reviewing threads about IP's, smoke, etc.

I have a 1993 300d 2.5 turbo just clocked 200k miles that put out quite a bit of black smoke at idle. The injectors were loud and I did a direct purge with no change. Bought 5 new Bosh injectors and install them this weekend. Injectors are much quiter and engine seems a bit smoother but .... still lots of black smoke @ idle.

At idle the engine will idle for 14 sec with little black smoke, drop a few rpm and chug black smoke for 14 sec, idle back up a bit and idle with little smoke for 14 sec, this continues.

I notice the most idle smoke when stopping for a traffic light, it's quite heavy

Can't see the black smoke while on the road unless drive the peddle down, then get some. Car runs smooth and avg 35 mpg.

Spoke with a diesel IP shop that rebuilds IP's and they think the governor is bad or idle spring, would not offer quote to repair.

Any ideas as what I can check before I go the IP shop route.

Thanks