Fuel Grade and More...

[Faraizim]

Hi-

A few questions I'm hoping some folks can take a stab at:

1. what fuel grade is recommended for the SL?

2. I recently acquired mine from California. I live in Utah. It had sat for a solid five months prior in California, but was a solid runner with a new cylinder head, clean running, well-maintained, etc. When she arrived to Utah from sea level (elevation 6,000 feet where I am) she is incredibly sputtery and stinky. Perhaps I've heard a backfire or two, but not confirmed. But going through the gears sputtery and stinky sums it up well. In fact, on my first emissions test try here (no less strict than anywhere else) she failed miserably.

My questions regarding point #2:

+are there suggestions for adjusting to altitude from sea level?
+are there suggestions for improving the emissions?

Perhaps the two suggestions/remedies are related?

I've yet to do the Italian tune-up, she's only been driven at 40 mph around the city for maybe 45 minutes since I got temporary tags yesterday, and maybe the Italian could be part of the remedy?

If anyone wants to take a stab at this, I'd be very grateful. There's basically one respectable Mercedes shop in Salt Lake City (as far as I know. comically, or sadly, the major mercedes dealer technician told me, "i have no idea where to start on the emissions question.") and despite moderately trusting the smaller shop, I feel that if I came loaded with some possible scenarios provided by the more astute members of this board, they would at least have better direction.

Thanks as always.

P

[Jonny B]

I always use the high grade fuel that is available, usually Shell.

If the barometric compensator is functioning properly it should adjust the fuel injection pump for the change to the altitude in Idaho. Others will be weighing in on more details on this.

If the car has been setting, another thing to check is to make sure the linkages are properly adjusted, there is information on the site for this.

It would be helpful for you to explain a bit more about the emissions concern. Is it about the emission equipment or to adjust and make sure the CO is correct. There is pretty much only rudimentary emissions stuff on these cars, although the later cars do have some electronics. The early cars pretty much have none. One way I have described it, these cars probably pollute more sitting in the garage with the engine off, than a modern car does when it is running.

[Benz Dr.]

I use regular. Engine is tuned to run at 36 degrees full advance. It doesn't ping ever. Compression is about 175 PSI. It's all in how the engine is tuned.

[jeffc280sl]

There is a barometric compensator (bc) on your fuel injection pump that is supposed to adjust the air fuel mixture with altitude changes.  Mine was broken and made no adjustments with altitude.  I'm at 600 ft and lower so it was not a big problem.  Read up on this item using the search function.  If the car ran well Cali then I would consider indexing the barometric compensator and then remove a shim.  Then in quarter turn increments turn the bc to see is the car runs better.  You can place a rubber hose between the bc and the pump to hold it in place during a test run.

[Faraizim]

Thanks everyone! I've printed out this thread and will be taking your responses to the mechanic to hopefully reduce shop time next week.

Also, is there such a thing as requesting a 'basic engine tune' on the SL?

Thanks again,

P

[J. Huber]

Also, is there such a thing as requesting a 'basic engine tune' on the SL?

I think if you find an independent shop that has some Pagoda experience, this request would be a reasonable one and -- might entail: points, plugs, and adjusting the timing. I would also ask that the fuel filter and the oil & filter be changed. These are basic things and should be fairly inexpensive. And they could make a world of difference.

Obviously, depending on the state of your car to begin with, there could be many more things to consider. This would take it from basic tune up to major engine tune up? Valves, new coil and wires, coolant flush, etc. More pricey.

[Faraizim]

Thanks for all the responses. I'll report back shortly and share what the shop ends up doing and compare my original failed emissions with the second go around. On a side note: I drove her for the first time today ever at 50 mph with the top down (i just got the car only recently) in a mountain canyon in salt lake city. despite running dirty, i must say that the car is worth all of the headaches and bills...so much fun to drive! She's got great spirit and pep.