I am getting my '83 240d roadworthy, and I was checking for leaks in the exhaust using my usual method of blocking the exhaust with my hand and feeling how much back pressure there was.

I was very surprised that after only a few seconds of blocking the exhaust (with the engine idling), the engine stalled. I re-started and repeated the test- stalled again. It must be pretty weak when idling. Maybe I'll get an assistant to rev the engine and I'll try again.

For comparison, I tried blocking the exhaust on my skid loader with a Kubota diesel. There was enough pressure coming out the exhaust that I couldn't even block it with my hand, and certainly couldn't stall it.

Does it sound normal that a 240d would stall so easily by blocking the exhaust?

Well, you probably don't have any exhaust leaks at least

I don't really know, but very weak exhaust valve springs would do that (backpressure opens valves when they should be shut, causing compression loss etc)

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

Killing the engine that way is not a test of anything that I am aware of. If it starts and runs fine I would not worry about it.

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[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.

A few months ago I adjusted the valves and all seemed good- no weak springs that I could see. The engine starts up immediately and runs great. 208k miles on the car.

X2

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

That was in Beverly Hills Cop. Eddie Murphy stuck a banana in the cop's tail-pipe. A gas engine, but same deal, needs air to burn and no outflow yields no in-flow. Perhaps the Kubota engine has a heavier fly-wheel, so harder to stop it. I recall really old tractors had a massive exposed flywheel on the side.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

So quit trying to find something to worry about. Some of us have actual problems!

-Rog

At some point when you have the injectors or glow plugs out, do a cylinder leak down test. The exhaust valves may leaking and your added back pressure increases effective EGR at idle.

Otherwise, if this car has an EGR valve, it may be leaking causing a similar effect.

Thanks for the useful reply. I am just getting this car ready to drive for the first time since I bought it a year ago. I have only done very brief test drives, and I don't really know how strong the engine is supposed to be (I know they are underpowered).

I am considering disabling the EGR by pulling and blocking the vacuum line to it (as suggested by an MB expert I know). He says it will run a bit better that way.

Well... It's not just that it will run better with the egr disabled.

EGR will load soot into the oily intake charge. The soot builds up on everything in the intake, and reduces air passages to the motor.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

EGR is defeated at idle and WOT.

I realized that, leaking exhaust valves and high back pressure will give an EGR effect at idle. With a leaking exhaust valve that is closed and piston going down to admit air, high exhaust back pressure will let exhaust gas enter the combustion chamber. This is the same effect as the EGR valve admitting exhaust gas into the intake. Still think I'm wrong?

As for post 9, if the EGR valve is leaking gasses, puling the vac hose won't help much. If the vac hose is somehow plumbed to a constant source of vac it would help.