I bought a 1985 500 SEL. Beautiful black. Bought it Thursday. It has been driving fine. Small puddles of oil and tranny fluid on the floor.

The previous owner recently replaced the tranny with a used one.

I have put about 200 miles on it. Tonight, on the way home from work, and on the expressway at 60, The front end start shaking violently. I knew I had a bad tire, so I thought the tire blew out. I coasted off to the side, as the engine died. The car would not re-start. The tires are fine. The oil is still golden in color. Removing the valve cover cap, the cam shaft visibly turns fine. The tranny fluid is red and fine. No silver. The radiator fluid is fine and still green, with no milky residue. No fuses seem to be blown. The engine turns over fine. Not too easy, not too strained. I could not tell if it was getting gas, because it is a 5 litre engine, and has a big flap on the carberator. I pushed down on the flap and tried to peer into the carberator, but I saw no gas with a crank-over. Perhaps the gas squirts under the second flap which is the butterfly one?

Any ideas?

I'm probably one of the least mechanically inclined people on the message board ... but the carburetor?

To my knowledge, your 5 liter V8 is fuel-injected. (Hence the E for "Einspritzung" in SEL.) ... There should be no carb.

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-- 1983 300D, acquired 10/19/2005 at 215,000+ turbodiesel miles ... engine croaked almost immediately ... back on the road at 217,210 with a 144K turbo motor from a donor '85. ... May 2007, replaced radiator. ... Now (2/28/08) about 240K miles and dead due to battery?

The flap you pushed on is the air flap that controls the amount of fuel injected by the injectors . If you could push down real easy, there is no fuel pressure and most like the fuel pump or it's relay are bad. Pushing down on this flap very soon after shutting off the engine will sometimes make a faint squeaking noise as some fuel is injected into the intake runners.

Get someone to crank it while you push gently on the air flap...if resistence increases while cranking, this indicated there is fuel pressure.

The pump(s) sit under the rear passenger side just behind the axle shaft.
They have a plastic cover over them. 10mmm socket on 6 inch extension reaches the nut through the access holes.

There you can check for 12 volt whilst cranking.
Relays on these fail too.
There is an OVPR , but I can't remember where it sits on that model.
It supplys power to the CISe fuel system.

Excuse me for asking...but......errr... it didn't run out of fuel did it ?

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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

dkveuro

Nope, did not run out of gas. I put $10 in it that morning on the way to work. The fuel guage does not work anymore, I am told there is a fuel sensor behind the back seat somewhere, and that may be the fuel guage problem; has three prongs on top?

What do you think caused the violent shaking? If the fuel relay went out, and fuel stopped being pumped to the engine, would the car act that way at a high speed?

Not being a 'fly on the wall' when it happened, I can only hazzard a guess.
You have bad engine mounts.
You have bad center drive line support.
You have periodic wheel sympathetic unbalance.
You stopped with the tyre bulge at the bottom.
Transmission was hunting between gears after power loss.
Bad road maintinence by local authority.
You passed through a time warp .

10 dollars worth of gas in a 500 will make the tank floor damp and that's about it ! That equates to just over 3 gallons...the fuel lines hold that much !
Those beasts get 5 to 8 mpg during the warm up cycle. If you accelerate onto the interstate at the same time, think 4 mpg.



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__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

You ran out of gas.

The shaking was caused by the motor not running on all cylinders.

Not good on a fuel-injected vehicle, as running the electric fuel pump dry is not good for it.

Very bad idea to run such a car without a working fuel gauge.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I would not be so quick to think it ran out of gas. I was not out when I put in the 4 gallons. I had over the weekend put over $40 in it.