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+--- Thread: Air in the lines? (/showthread.php?tid=1433)
Air in the lines? - Tim Wheeler - 06-15-2010
I recently picked up a 1982 300SD. It had been in a garage since '96.
I bought if from a guy who got the car from the garage owner, changed out some rubber and got it running. I think most of my challenge will be the work he did to get it running, but that is for another thread.
It has 137K on the engine and when I got it the top of the fuel filter housing was wet.
It would start smooth, and all the glow plugs are good, but after about 10 seconds it starts to miss, and then clears up.
I changed out the fuel pump washer and that leak is gone. I also changed out a line at the fuel tank that was weeping fuel. Still have the symptoms.
Also in the mix is a RAM air/water separator system that replaced the inline fuel filter. Its mounted behind the driver side headlight. Big machined aluminum canister. No indication of leaking, but I don't know if I'll be able to find filters for it... will probably switch back to the inline system.
My experience tells me that missing is caused by air in the lines.. although I can't locate any other obvious entry points.
Also, occasionally after starting, the engine will lope excessively at idle. Idle is right around 800RPM, which if I can remember is where it should be.
Running at speed, though, pickup is awesome and the car responds excellently.
I'm planning on running a can of purge through the system soon...
Other that than, does anyone have any suggestions?
RE: Air in the lines? - Alastair E - 06-15-2010
Worth dropping out the tank gauze-strainer and clean it. Will give you an idea whether there's microbes in there too!
When you changed the spin-on fuel-filter, Did you change the 'O' rings too...?
RE: Air in the lines? - Tim Wheeler - 06-15-2010
Good suggestion. The guy said the tank was "pretty much" empty when he got the vehicle. Probably not.
Microbes are a possibility, though. What kind of treatment should I do to the tank?
Could air be entering through the fuel tank, though? What would cause it to temporarily miss after setting for an short period?
RE: Air in the lines? - rdirtycar - 07-10-2010
If there is no hesitation accelerating up a steep hill the tank fuel screen can't be that clogged. My guess is the lift pump is sucking fuel from the fuel tank through a partially clogged fuel tank screen and the vacuum created in the fuel water separator behind your headlight is pulling a little stream of air through a dry o-ring in the separator. I think that lift pump circulates quite a bit of fuel doesn't it? There may be a hole in one of the supply lines under the car weping just a tiny little but of air enough not to make a spot on your driveway big enough to notice. I have many spots that form myself. I don't think I'd notice a new one until it got pretty big. A hand vacuum pump tester would tell you if you're letting air into your fuel lines. Undo the fuel hose at the tank, plug it, right? And disconnect the supply line from the lift pump, apply vacuum and gauge it's loss with a vacuum gauge.
Cleaning the tank last year I removed the tank from the car, plugged the supply and return lines, got myself five gallons of regular unleaded(I know), put a little in the tank, and rolling a shaking the thing rinse after rinse of about half gallon each rinse. So much black stuff came out you wouldn't believe. It is an absolutely horrible chore but I had to do it, the car would run for awhile down the road and then stall. And then after a few minutes would start and run again just fine then stall. Over and over. I would immagine glass beads or ball bearings or even stones of the right size rolling around in there with the gasoline would help remove more of the sludge. I still get black particles in my second fuel screen.