My 87 190 2.5 turbo diesel continues to be a bit rowdy on cold start. It smokes and shakes for a bit until it warms up. The glow plugs are new and most of the obvious culprits have been addressed. I'll eventuality sort it out.

Anyway, here is something I noticed...

Immediately after starting the car, I throw it into reverse and back it out of the garage... It would appear that the car runs a lot smoother and there is significantly less smoke when the car is in gear and the accelerator is slightly depressed.

If the car is NOT in gear and the accelerator is depressed slightly immediately after a colt start the engine will run rough and smoky.

It would seem that a slight load on the cold engine helps cut down on smoke and the engine runs significantly smoother.

Any ideas as to what is going on?

How new are the injectors? Pop tested or checked for spray pattern recently? Compression? How many miles on the engine, original head and valves? Do you have the fuel heater and have you bypassed the thermostat? Any obvious fuel leaks?

"the obvious culprits" is a pretty sweeping statement. There are lots of things that will cause a rough cold start, glow plugs on a pre-90s vehicle are only glowing until the engine is started, then they're out of the circuit. Afterglow didn't show up until somewhere around 1990.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

87 190D turbos: om602.961 have afterglow and inclined injectors but not the shorter glow plugs on the .962

190dt has afterglow, the plugs remain lit for awhile after starting. Check for leakage around the delivery valve seals. Other than that, don’t get crazy. My 190dt has always been a bit smokey in the AM. If the car lives past this summer, I’ll recap the EDS computer, which may cure a few annoying problems.

Hmm... Sometimes I don't include all the details because no mater what folks tend not to read a wall of words. My bad.

the obvious culprits that I have checked or repaired....

Compression is very healthy and was well within specs.

All five injectors were disassembled, cleaned and pop tested. They all had great patterns and popped at 1950 psi.

Delivery valve seals were replaced a month ago.

Fuel thermostat was removed from the car due to a leak.

IP timing verified.

timing chain stretch almost non existent.

Air in fuel lines was checked using several methods. Verified no air in fuel lines.

Fuel filters have 2500-3000 miles on them

EGR disconnected.

Wastegate actuation verified. Max boost 14 PSI.

All the Hydraulic lifters were replaced 1500 miles ago

All glow plugs were replaced 700 miles ago.

Glow plug relay was verified in good working order.

All glow plugs get power during start up.

Diesel purge done 3000 miles ago. the fluid looked clean during the purge.

Engine has 220K miles. As far as I know the engine is original and has not been apart.

The car runs well and except for the smokey starts i'm very happy with it. The fuel economy when the weather is above 60F is typically 34 MPG.

So back to the original question, any reason why the smoke seems to be less when a slight load is put on the engine during a cold start?

I'd take the glows out and test them visually. Classic symptoms of a inoperative glow or two.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

You've got a bad motor mount?

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Put the fuel heater back. The EDS system assumes stable fuel temperature. Despite the stuff you've removed, the EDS system still tries to control idle fueling based on temperature and load. If you like playing games, you can unplug the ELR and see if you can manually adjust the pump to something you like. There's a screw on the back of the pump that will allow adjustment when the electronics is disabled.