New Member/New 380sl Need help

[82gray380]

I just bought a 82 380SL and think I'm going to love this car. I own several different model convertibles and ragtops and this car appears to be one of the better ones.
Anyways, heres the story, The P.O. had it stored for around 7 years, starting it every several months and driving it around 100 miles in that time. He had added sta-bil to the fuel when he stored it, but I'm sure the fuel is bad. When I picked it up, I added Seafoam to the tank and 5 gals of fresh gas (that filled it up). I drove it on the expressway, 60 miles to get it home and it ran great at speed, but idles very poorly (as expected). I'm trying to run the old fuel out and let the Seafoam do it's cleaning, but in the mean time, I'd like to increase the idle a little, so it doesn't die at stops. How do you adjust the air/fuel mixtures on these cars. I've worked on many different cars, but have never seen an injector system like this 380s. I can't seem to find any adjusting screws on it.
Also, I keep hearing a hissing sounds coming from the rear by the fuel pump/filter. Is this sound normal for these cars or is my pump going bad. As I mentioned before, this car runs great above idle, so I can drive it if I can just get the idle up and as soon as the cleaner and old fuel go through the system and I add fresh high octane fuel. I hope it will clear it all up.
Any constructive advice or suggestions would be greatly appreciated.
If you want to see some of my other cars, go to cardomain.com/ride/816145 each car has it's own seperate page on the site also. thanks in advance

[ctaylor738]

The idle is electronically controlled, and the mixture is adjusted by measuring the on-off ratio. Lots of posts on this, try a search.

To raise the idle, you can you can:

- uplug and bridge the connector at the back of the rear of the right cylinder head. This will make the idle relay think the engine is cold

- unplug idle control valve at the front of the intake manifold - idle should go to 1200 rpm or so

- adjust the throttle linkage to open the throttle plate a bit.

[82gray380]

ctaylor,,, thanks for the reply and information. I just ordered a repair manual for this car and when it arrives, I'll start to find my way around the engine bay. I realized yesterday that I better either get knowledgeable about this car or get a second job to pay someone to fix it. I called the local Mercedes (all foreign) repair shop and asked about them changing the trans filter/fluid and got a price of around $180......I bought a trans kit and fluid and did it myself yesterday afternoon for $45.
I did look over the engine compartment, but I want the manual in front of me, so I can figure out all the hoses and electrical items.
thanks again

[ctaylor738]

You're welcome.

The thing to remember about these engines is that they only work right if all the pieces are good - fuel system, injection system, idle control, O2 sensor, lambda system, tight vacuum, etc. There is almost nothing you can do by way of an adjustment to make up for a marginal piece.

In your case, I would be surprised if not astounded if the car didn't have problems with the old gas, especially fuel tank corrosion, a clogged tank strainer, or gummed up pump, fuel distributor or warm-up regulator. Not saying this to scare you, but if you start to have issues, that's where to start looking.

[82gray380]

Just an update. I added Seafoam injector cleaner and ran the old gas down to under 1/2 tank. This was after I changed all the fluids, oil, trans, diff. antifreeze. The engine smoked during most of the running of the old gas and cleaner out. After that I filled it with 93 octane and added some more cleaner and the engine began to smooth out and most of the smoke stopped. I haven't had enough time to get it out on the road, but that is my next plan, as soon as I can put a couple of hundred miles on it. I hope that will clean all those gummed up parts and areas. After that, I'm going to replace the fuel filter and check the fuel pump. They both appear to be almost new, so in the past, they have already been replaced. As I said, it already seems to be running better, so with additional cleaning and fresh gas, it just might do the trick. I will let you know and wish me luck.