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1985 500sl
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5 Posts
Discussion Starter #1
I have a 1985 500sl which will not start on its own. The car had been sitting for the past 4 years. The car will start and run for a while if I pour some fuel directly into the manifold. So for I've replaced both of the fuel pumps, one of which didn't power up, the fuel filter, the spark plugs (squirted a little oil into each cylinder since I was there), pulled the fuel distributor apart and cleaned it. I seem to get fuel to the distributor but no further. My owners manual is in German so thats no help there.

Now I'm at a loss, does anyone have any suggestions as to what to try next???

Also has anyone found the stock alarm on one of these?

Thanks in advance
 

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1998 S210 E320 black/mushroom, 1984 R107 500SL #3904 black/black
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58 Posts
I have a 1985 500sl which will not start on its own. The car had been sitting for the past 4 years. The car will start and run for a while if I pour some fuel directly into the manifold. So for I've replaced both of the fuel pumps, one of which didn't power up, the fuel filter, the spark plugs (squirted a little oil into each cylinder since I was there), pulled the fuel distributor apart and cleaned it. I seem to get fuel to the distributor but no further. My owners manual is in German so thats no help there.

Now I'm at a loss, does anyone have any suggestions as to what to try next???

Also has anyone found the stock alarm on one of these?

Thanks in advance
If the car has been sitting for four years without being driven then it could be the fuel distributor. There is a diaphragm in the fuel distributor which dries out and looses functionality both from the aging process and from the old fuel "turning to varnish." It needs to be pliable to function correctly.
 

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Previous: 1989 190E 2.6, 1997 E420, 1985 380SL, 1975 450SLC
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747 Posts
Sitting for the past 4 years? You'll want to dump and then replace *every* fluid in the car, beginning with the fuel in the tank. First and foremost, don't run that nasty old gas through your fuel system or more bad things will happen.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,314 Posts
Two fuel pumps????:confused:
What do you want to bet it was built in late '85 which would make it an '86 model. If it is it may be KE jet.

Either that or some one has messed with the fuel system. Or it is not a 500SL. The VIN would tell all.

Factory alarm connectors are behind the glove box. AFIIK the factory alarm was only on 1986-89 models.
 

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1985 500sl
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5 Posts
Discussion Starter #7
These did have two fuel pumps both in a bundle along with the filter and accumulator. Since I'm not rolling in money I found some used pumps off of a 1994 190E, it has the same Bosch part number and I was able to get both pumps with a 30 day guarantee for $33.

Last night I pulled the gas tank. Turns out it was replaced in 2006 as it still had the shipping tag from UPS attached. There was some sort of rectangular plastic piece with raised plastic spikes broken off and loose in the tank. It was about 4" X 6" and I would guess it was an anti-slosh thing.

I emptied the tank of the little fuel that was in it, about 1 gallon. I pulled the filter screen and cleaned it, about 1/2" at the bottom was gunked up but nothing too bad. Put 5 gallons of fresh fuel in it and...still no start.

Tonight I'm going to try some Sea Foam and let it sit till tomorrow, maybe that'll do something.

Thanks to all for the advice, I'm trying them all.
 

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Always Remembered RIP
1979 280sl 4 sp w/ac 1957 MGA 1998 volvo xc/70 2004 F150
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6,050 Posts
You really should read thru the EGv-107 sticky in blue at the top of the posts. This is in there.

Model 107
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,314 Posts
These did have two fuel pumps both in a bundle along with the filter and accumulator. Since I'm not rolling in money I found some used pumps off of a 1994 190E, it has the same Bosch part number and I was able to get both pumps with a 30 day guarantee for $33.

Last night I pulled the gas tank. Turns out it was replaced in 2006 as it still had the shipping tag from UPS attached. There was some sort of rectangular plastic piece with raised plastic spikes broken off and loose in the tank. It was about 4" X 6" and I would guess it was an anti-slosh thing.

I emptied the tank of the little fuel that was in it, about 1 gallon. I pulled the filter screen and cleaned it, about 1/2" at the bottom was gunked up but nothing too bad. Put 5 gallons of fresh fuel in it and...still no start.

Tonight I'm going to try some Sea Foam and let it sit till tomorrow, maybe that'll do something.

Thanks to all for the advice, I'm trying them all.
What Werner and I are saying is the 1985 model did not have 2 fuel pumps. It only had one. If yours has two it was either modified for some reason or is a 1986-89 model. There are quite a few differences in the two model years as far as the FI system goes.

To begin diagnosing you first have to determine which system you have.
 

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1985 500sl
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5 Posts
Discussion Starter #10
Rowdie, you and werner are right. The title lists the car as being a 1985 which is what I've been going by, it didn't occure to me to check the door tag till I read your post. It is a 1986.
 

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1978 280slc
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3,203 Posts
Try cranking the car a few times then go and crack the metal lines at the fuel distributor. Fuel should come out of the injector lines, no fuel past the distributor would mean a plugged up fuel distributor or blogged fuel line. These injectors need something like 70psi to open and spray so even a minor drop in fuel pressure could prevent the car from starting.
 
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