An owner selling his 84 300SD described the car as running well when warm, but it is sluggish for “a few blocks” and then it runs more strongly.

If this were a gas car, I would immediately go towards the fuel mix being off when cold, but this being a diesel - ???.

Is it possible that this is an effect of the engine compression being low due to piston/ring wear, and once the heat has expanded the pistons it then has more compression, therefore running well “after a few blocks”? Or, is there a turbo related issue, such as the wastegate blowing off manifold pressure when the engine is cold?

I know, I know, a compression test is in order – but I’m trying to boil down the selection of cars to choose from rather than compression check half a dozen cars.

THANKS AGAIN EVERYONE!

for a diesel - they run best after they are warmed up to operating temp.
Jim
'85 300D
'95 E320
'97 CRV

This is typical, however, I have seen where the internal portion of the anaroid wears resulting in a leaner mixture.

In this case, we richen the mixture up slightly and the car will really get up and go then.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

having just had this problem with my benz you need to figure what he means by sluggish? Trany does not shift does it hesitate if you floor it? does it choke ?What is meant by sluggish? Some things I can tell you to check (this is what they billed me for) air cleaner dirty? turbo bypass hose may need replacing or cleaning valves may need adjusting? or diaphram on the injector pump.Also check to see if the throttle is going all the way to the full wide open position.some simple things that need to be checked or answered to help with you decision.
pete

were worn wouldn't it run like that even after it was at operating temp.

OT - at work I fill in for the guy that runs the motor shop when he is off on vacation. We recently had a chip pusher in because it was "low on power". A chip pusher is a REALLY, REALLY BIG piece of equipment that pushes chips to the conveyor system that feeds the papermill. Anyway, the engine, a Detroit V8, 2 stroke diesel, was rebuilt about 6 months ago. I called the guy that rebuilt it and he spent about a day adjusting the valves, changing filters and everything else you try to do when a diesel is low on power and it was still low on power. Finally, he dug into the engine a little deeper - come to find out the metal screen that fits over the inlet to the supercharger was severely plugged with chips, grease, oil and debris which was restricting the air flow to the supercharger. He removed the supercharger and screen and cleaned everything up and the power was restored. Moral of the story - keep those air passages clean.

Jim
'85 300D
'95 E320
'97 CRV