My first non diesel-powered Mercedes Benz and the problems that come with it...
 

All right, I did it. I bought a gas powered vehicle. Against my principles... A 1974 Mercedes 450SL.
Ok Ok I have a couple vw busses, but they're simple carburetor vehicles and if I could, they'd be diesel (Subaru boxer diesel) or electric powered. But that's too much work for now.
Anyway, I bought this mistakenly. Long story, but now I have it. And have to do something with it.

The car ran when I purchased it, pretty good for a gas motor actually. Not too evenly, kind of like in need of a tune up. It was on a non-op for 20 years. The owner said it would be driven around every now and then to keep things going. I paid him, and drove off. After 3 miles on the freeway a clunking noise appeared, as if a center driveshaft bearing had torn it's rubber so I took the next ramp and drove back towards the seller who at the time had a garage, sort of. Basically a lift and a guy working on his cars, he's a collector. On the way there I passed a parts store and decided to buy a bottle of Lucas injector cleaner. Why not, it's a gas car, I'm sure that nasty old gasoline has by now left all sorts of deposits everywhere...
Well it did. And all those deposits came loose I bet, the car started running rough after about 500 meters... I barely made it back to the guy. When I got there it died. Of course he "couldn't get back on the deal", but was willing to put it on the lift and let me work on it.
Nothing wrong with the center driveshaft bearing so I gave up on finding out what that clunking noise was.

Took the tank out and emptied it. then threw a couple handfuls of gravel in there and sloshed that around. Did that for a few hours on end, each time less rust and garbage came out with the gravel. Eventually it appeared pretty clean so I started sloshing gasoline around, and emptying it through a filter, and repeating the process. Did that for a few hours more and got it pretty clean I must say. Not the best afternoon I ever had in my life. The smell of gasoline is just so much more horrible than diesel.
Installed tank, changed fuel filter, filled it with 5 gallons of premium and a bunch of seafoam, hooked up a battery to both pumps and let it run until about 2 gallons had worked it's way out the return line, which I unhooked to go into a container underneath the car, hoping it would clear the lines.

Then I thought, well, let's start her up. Nothing. Not even a spark.
most problems don't come alone, I figured, so I threw a bunch of parts at it. I don't have any measuring tools so that's all I could do at the time. Plugs, wires, cap, rotor, coil. Nothing. Then I let it sit for 6 months as I was away to beautiful Europe where way less people drive a gas powered, let alone a V8, vehicle because it's just simply not economical.

Then I came back to the US and it just fired up! For a couple seconds. All this time in solitude must have made it self-repair! But it runs so rough that you can't even keep it going for 15 seconds. Injectors, I thought, so I checked the one that gives some extra fuel when it's cold. It squirted when 12v hooked up. I tested 2 more and they both worked. Then I figured, all the rubber end pieces are dry and o-rings and lines are too, I bet there's vacuum issues.

That's where I'm at now.

Any input welcome, also, what's the best place to buy the necessary rubber end bits and o-rings etc, what kind of fuel hose can be used between rail and injectors, anyone in the Inland Empire who wants to play with this SL??

Help! I have a great 603 sitting around, I'm pretty tempted...

I have discovered that the early gassers with fuel injection have high failure rates starting at 30 years after they were made. Yours is almost 40 years old!

I'm betting wiring is gouing to be a problem.

This is what happened with my 1972 Citroen that I bought from a museum. The wires were all waxed and pretty but corroded inside the perfect-looking insulatuion.

You may need to do a lot of continuity checking.

I'm saying this from experienced but there are are some early Jetronic experts here as well.

With my 380SL, I am seriously tempted to install the first good 617 turbo I can get from vs tech.

Right now, have to spend time finishing the building of the workshop 2nd floor and the insulation

My thoughts and prayers are with you as you do this.

It's like crossing the jungle and finally getting to Timbuktu.

Classic!

gee, great help!

well meanwhile let me replace injector seals and test fuel pressure some. It gets a spark.
If I can't get it running right, it's diesel time. Gas motors are so backwards.

I haven't personally messed with it, but I've heard great things about Megasquirt.

a repair job in a bottle???

No this a brand name of sorts related to a user programmable electronic fuel injection (EFI) and electronic ignition system.

With lots of modifications you can junk the old Mercedes way of doing it and put in something that will (or has the potential to) do a better job.

Some people do this because they want more power => go racing

Some people do this because it can be tuned to provide "diesel owning-like" fuel economy

sounds good but I think I'll just get it sold before I light it on fire... I'm very much not charmed by gasoline cars at all. This is a personal preference. I should never have bought car with a computer in it, it's against the rules of reliability

I think you are quite right. I feel very much the same way about my W201. But I do also realise that electrickery is something I just need to get used to - modern diesels use it these days too (I'm sorry to report).

then again in the Netherlands you can now pick up 250d's and all those older benzes cheap. they don't have computers and still get 15 km to the liter.. Better engines than the new ones in my opinion, way more reliable. Too bad Mercedes RUSTS so incredibly fast due to terrible design flaws all over their cars...

They are cheap for a reason. As an inmate I'd have to pay nearly two thousand euros a year in road tax for a W201 250D. And it does unfortunately have a fair amount of electrickery. However in France I reckon you'd do well buying an OM602 powered something up here and then migrating back down south...