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Discussion Starter #1
I believe my 82 500SL has ABS. I think it works because I've stopped pretty hard on some sandy road before several times and could hear and feel the brakes pulsating. The problem is the ABS light on the dash never lights up when you turn the key. Is the ABS working all in my imagination or could it be the it was deactivated when the car was Federalized? I suppose the bulb could just be burned out too.

Do these cars have any kind of buzzer for the headlights being on or the key being left in the ignition? Just curious.

Oh, and since I'm thinking of it, do these cars have a secondary fuel pump in the gas tank? I had a 1986 Volkswagen Jetta GLI (which I loved. It was even a Wolfsburg edition) that had two fuel pumps and was wondering if this 500SL had a similar set up. I have the Bentley book on Bosch Fuel Injection and don't see any mention of two fuel pumps in the K-Jet section. The reason I ask is because I don't seem to hear the fuel pump buzzing when I turn the key, but the car starts (albeit with a little gas pedal pumping). Maybe I'm just deaf now, but I can definitely remember hearing it buzzing on my Volkswagen.

Anyway, I think I've filled my question quota for the day in this one post!
 

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You can run your VIN on the Russian website or simply look on the front of the passenger side of the engine bay for the unit.

No secondary fuel pump. Hard start could be the cold start valve or the fuel pump relay. Fuel pump should run for a few seconds when you turn the ignition on then it runs when cranking and engine running. No pumping should be needed.

How is it on hot starts?
 

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Discussion Starter #3
Sorry, when I posted this last night I couldn't remember what the VIN decoder told me when I ran it a few months ago. I'm at my parent's house which is 1,300 miles away from me and didn't have the VIN handy. I managed to get the VIN from my insurance company's website and ran the decoder again. The car has option code 470, which is anti-lock brakes. I'm guessing the bulb is maybe burned out since they seem to work. I might not be four channel ABS though.

About the hard start. It seems to be more difficult to start when it is hot than cold. A lot of times I have to crank it longer and pump on the gas. It idles high too but that's another issue I'll deal with. One problem at a time!
 

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Sorry, when I posted this last night I couldn't remember what the VIN decoder told me when I ran it a few months ago. I'm at my parent's house which is 1,300 miles away from me and didn't have the VIN handy. I managed to get the VIN from my insurance company's website and ran the decoder again. The car has option code 470, which is anti-lock brakes. I'm guessing the bulb is maybe burned out since they seem to work. I might not be four channel ABS though.

About the hard start. It seems to be more difficult to start when it is hot than cold. A lot of times I have to crank it longer and pump on the gas. It idles high too but that's another issue I'll deal with. One problem at a time!
Excellent car, but I'm biased as an '82 500SL was my first SL. That ABS on such an early car is indeed a rare and fancy option. The steering knuckles and rear differential case have threaded holes for the speed sensors which detect wheel slip and allow the actuator to act accordingly to modulate brake pressure above a road speed of 30 MPH. The light should turn on during startup and again if battery power is too low to operate the actuator. If you feel grinding/pulsating (assuming the rotors aren't warped) then chances are it's working, the bulbs were not removed for Federalization, it's probably just burnt out. There are many articles on puling the steering wheel and instrument cluster to address that. The steering wheel is horrible to remove, the instrument cluster requires connectors be loosened, including the oil pressure fitting (10 mm I believe) to extract far enough to get to the bulbs at the back of the instrument cluster.

As this is a first gen system (used til 1986), the pumps and controllers are a bit different after 1986 when ABS became standard. The cost to rebuild is about the same, about $150-$400 for worst case, if that proves necessary. From the description, bleed the system, check all electrical connections and speed sensors electrical connectors and you'll probably be fine.

As for fuel:
As a pre 1986 car, the normal fuel pump assembly is probably a 3rd revision assembly with pressure relief crossover and a single pump, fuel filter and fuel accmulator. The system uses a lower fuel pressure than the 1986 and later cars. The fuel pump assembly is external to the tank and just below the fuel take outlet, attached via reslient mounts in a plastic shrouded cage, with a very large diameter pleated rubber hose leading to a fuel damper with a 90 degree bent to the fuel pump inlet. It's easily serviced and can be completely removed in a matter of minutes with a clamp at each fuel line leading into or out of the fuel pump assmbly, which is the best way to replace components rather than doing this while you are wedged under the car.

As for you refuel related complaints:
If the car has been sitting a long time, chances are varnish and gum has affected the fuel system and will require R&R to resolve. The quick and dirty fix is to drain the fuel completely, flush the tank with methalated spirits straight out of the fuel outlet strainer with no hoses attached and fuel pump assembly detached and check the tank for rust and crud in fuel tank strainer and overall condition of the hoses. A fuel injector cleaner may partially restore spray pattern of the fuel injectors and free up the fuel distributor plunger, but don't count on it.

The fuel distributor orifices can gum up or the system can fill with rust from water deposition, the plunger may thus be sticking in it's bore. A through cleaning requires pulling the entire air distributor/fuel metering housing so you can open the lower and upper halves, clean the pivot points for the air metering flaps (often covered in dark red gum) and pull out the fuel distributor and douse so that the plunger moves freely and lightly oil, replace O-ring seal (MB part better than aftermarket, thicker diameter, better sealing) and refit and you may be good to go as long as nothing obstructs the individual injector plumbing ports.

For the same reason as above, the fuel injectors may be spraying a very poor pattern, which is generally only solvable by replacement of the injectors (which are cheap). The Bosch brass injectors are a good upgrade and don't take long to replace, along with associated holder and O-ring seals since both get brittle and fail to seal over time.

The idle control valve may be stuck in an open, closed or half-open position due to deposits, which can affect your idle speed dramatically. This is often easily addressed with a long soak in throttle-body solvent, Marvel Mystery Oil, etc. or similar. The electrical idle controller may not be working, but you won't know until you address the valve. The valve itself is the part that gets the crud, the electrical controller part behind the glovebox liner is often not the root cause.

Suggestion for overall better fuel system health:
I'd recommend starting this process by replacing the fuel filter and inspecting all fuel hoses and fittings from the rear of the car to the front. The fuel pressure accumulator at the outet of the fuel pump assembly can also make it hard to restart after initial warmup and shutdown because the fuel pressure will bleed off and fuel will often boil in the lines as a consequence. It's a cheap part to replace (about $60-$80) and easily diagnosed per the shop manuals, as well as easily replaced due to accessibility of the fuel system assembly directly in front and to the right of the spare tire compartmetn under the fuel tank and next to the right rear drive wheel.

Crank time on starting should not exceed 4 seconds, which can help trace (assuming correct battery voltage and good contacts on the electrical starter motor) a fuel pressure or flow related problem.

The cold start valve can leak or fail to spray within it's prescribed temperature range and spray duration. There is also a paper gasket between the cold start valve and the intake manifold port that should be replaced if your pull this valve out as it is often too dry and compressed to seal properly if you pull the cold start valve to inspect it's operation.

Depending on whether you have a frequency valve or not, the electrical connection can become so brittle that the electrical connection shorts and never actuates to trim the fuel enrichment, leaving the fuel on/off ratio at 60/40 (rich, as with full throttle and cold start warmup). This is probably not your issue on it's own, as rich mixture is easier to start, tends to run cooler and does not tend to cause issues under hard acceleration as there is often more than enough fuel. You can disconnect the frequency valve (if present, may not be on your Euro 500SL, my '82 did not have one) to diagnose without worrying about it.

I'd recommend going through the whole fuel system, it is probably over due if nothing has been touched since manufacture. You'll no doubt have rotting wiring insulators, partially clogged fuel injectors, cracked injector holders/seals, brittle air injection plumbing, gummed up fuel distributor and perforated diaghram/tired pressure spring in the pressure regulator, one or two fuel pressure dampers (depending on year and type, you may have one or two attached to the fuel accmulator) fuel assembly parts such as inlet lines, crossover, hose insulator, fuel filter, fuel damper at inlet, pressure relief valve, vapour canister hoses and purge valve, short hose from fuel tank vapour canister draught pipe to front charcoal canister, fuel return piping/hose and so on.

There are a lot of rubber parts to sort out, including the fuel tank cap which often has perished rubber seals if original.

I wrote up two fuel system service threads step by step. You can search the forum for these.

I did not include the following part numbers, which you will need if you find that you must replace the rubber air guide boot under the fuel/air metering housing with reinforcing aluminum rib, as it will likely be hard and brittle. The updated air metering housing has a smaller diameter for the idle vlave, a different plastic connector and connecting elbows. These parts should x-ref to the M117.96x motors as well, I've used them on 3.8l, and 5.0l motors. The 4.2L and 5.6L seem to have come fitted with these from the factory. These will also address some of the stalling behavior that the early SLs suffered when decelerating from higher speeds to a stop (say coming off a freeway offramp to a full stop at an intersection, common scenario for this type of stall).

Part numbers:
116 094 12 91
116 094 13 91
116 997 16 52

Double check these are current part numbers, they should cross-reference to M117.96x as the diameters are exactly the same to the idle control valve and attachment hose for the air-injection.

In any case, good luck, you appear to have a choice bit of covetted Euro SL kit!
 

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Discussion Starter #6
Wow BenzHacker! What a thourough write up! I try to absorb as much information as possible about engines and cars in general from reading on the internet and books. Cars have been a passion of mine since I was very young. I still have Hot Wheels cars that were bought for me from the early 1980's that are still in the box, never opened.

I see you own a Rolls-Royce Silver Shadow. I've always wanted a Silver Spur from the 1980's. Have to love that old school, push rod 6.75L engine with like a 4500rpm redline.
 

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The ABS Light on the dash should Flicker on briefly, then go off when you are starting up.
This is supposed to signify that the system is in order. If the light stays on, it could be
several other things wrong. I remember reading this somewhere.
 

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Wow BenzHacker! What a thourough write up! I try to absorb as much information as possible about engines and cars in general from reading on the internet and books. Cars have been a passion of mine since I was very young. I still have Hot Wheels cars that were bought for me from the early 1980's that are still in the box, never opened.

I see you own a Rolls-Royce Silver Shadow. I've always wanted a Silver Spur from the 1980's. Have to love that old school, push rod 6.75L engine with like a 4500rpm redline.
Hope that helps you, you are most welcome.

As for the RR, yes, she is a nice ride when she behaves herself. The Spur and Spirit are the same platform as the Silver Shadow with a face-lifted monocoque body atop it. I even have a 1980 Silver Spirit rear suspension waiting to be fitted, a weak point of the early Shadow and a bolt on job. They are great cars if you can devote the time, parts expense and attention to them, something I will be doing again more regularly with her next year. I might even rejoin the user group there, which hasn't seen a single post from me in about a year.

Let us know how it goes as your sort out your various fuel delivery issues and report back. I for one would like to hear how it goes.
 
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