I have not had my 190 running for many years. It will turnover and run with a little starting fluid shot into the injector intake. I have drained the tank with a siphon. Question is, should I take the tank out and clean it. I have the fuel line disconnected from the injector intake. What is the best approach? I could, with the fuel line disconnected put new fuel into the tank and turn it over till fuel comes out of the fuel line. Just wondering what is the best approach. It runs fine for a few seconds with the either shot into the intake.

 

If a car sits for more than a year the approach is to never attempt to start it before you have a chance to flush out everything. Tank, fuel lines, etc.

But you are past that stage now. Here is what I would do (and have done when my car sat for 7 months while I was working on transmission and clutch overhaul.

(1) I would not take the tank out necessarily but you can if you find it is easier. If left in the car take out the fuel level gauge and the strainer at the bottom. Power wash the tank until sediment/crud stops coming out of the strainer. Change the strainer, they are available on line or thru your mercedes dealer.
(2) undo the fuel return line at the pump (input to the fuel accumulator) You will notice some pretty bad fuel right there.
(3) With a air compressor set at around 30 PSI pressurize the input to the fuel pumps (the line you just disconnected from the fuel tank strainer) You will notice some bad fuel come out at the accumulator input. Do not go to much above 30 PSI, we do not want to blow out anything in your FD.
(4) Above 3 flushed out everything except your injectors as they need about 40psi to start opening (I could be wrong on this but is is higher than 30 psi I believe)
(5) You are ready to crank and it will take some cranking to flush out all the air you just pumped in the system and to flush out the bad fuel in the injectors.

You could flush out the fuel in your injector lines by disconnecting from the FD and blowing air at high pressure (4-5 Bar) and see what the fuel looks like but that is in fact what is happening when you go thru step 3, but you are using your fuel pump instead.

Good luck with this, these cars do not like sitting for extended periods. My car only sat for that 7 month period for the last 35 years, except for that one time. Flushing the fuel system is no fun.
When I replaced the strainer I was pleasantly surprised how clean it looked.

- Cheers!

 

I think that Dolucassi has put forward a solid plan for you to proceed with. In the future, if you're going to let your car sit for a long period of time, mix Stabil storage into a full tank of gas. The Stabil will prevent the gas from turning to varnish. Trying to start your car with the gas/varnish has now gummed up your fuel system and now you must go through the process of cleaning out the fuel system. Given the age of your car, you'll likely need to replace a lot of rubber that's likely deteriorated over the many years. Rubber suspension bushings would be a good place to start. Tire replacement is also another place.

 

Thanks, you are the best!! I do believe I will remove the tank. What is the FD? I was reading this and came up with Fire Department, but I'm sure that's not what you mean when you say fd.?

Again, thanks

randy

 

you are welcome Randy. FD is Fuel Distributor, the gizmo that the fuel injectors are connected to.

 

My car sat from 1999-2020. I say go ahead and replace the tank, fuel pumps and filter. It is unlikely that gunk will get past the strainer both fuel pumps and filter….i think itll
be fine with all new ones

I chased random stalls for multiple years up until replacing the fuel tank and O2 sensor, these would have been the very first things I tackled

 

I never realized that your car sat for so long. I will also say that since the OP started his car with the old, bad gas/varnish still in it, it's likely that the entire fuel system has been gummed up so a thorough flush of the fuel system will be needed in addition to replacing the tank, the fuel distributor, fuel filter and fuel lines. The fuel injectors at the least will need a good cleaning as well and possibly replacement if they're too badly gummed up from the bad gas/varnish.