Car sat for a year, now no power (om617)
 

1983 300d turbo

Gents, the car sat for a year. I couldn't even convince my family members to start her up for me. I came back to a bad situation. I replaced the battery, replaced the oil and filter, new fuel filter and pre-filter, and new air filter. Here's the problem, though:

When I start the car and let it run, sometimes it seems to start strong and stay running strong for 10 even 20 minutes. Sometimes after starting strong, it will sputter out and turn off on its own, even if I try to smooth out the engine by depressing the accelerator while in park.

After a long idle of at least 5 minutes, when I go to try to drive it, it loses power either right after a full stop and when I go to press the accelerator, or on uphills. On uphills it's usually completely gutless, but if I have momentum on the straightaway, and then use that momentum to turn onto an uphill, it seems to maintain its power.

In every case, when the turbo spools up, I get good power. But sometimes I come to a stop right after that good power, the engine sputters, and it even turns off completely. It never has a problem starting up again, but after it sputters out and I try to restart it, it restarts in sputter mode.

I thought a new fuel and pre-filter would do the trick, but it didn't. Oil pressure seems to be good according to the pressure gauge. I thought the diesel would have gone bad after a year of sitting in the tank, so I put about 5 new gallons of diesel in there to dilute what I thought was bad fuel. By the way the fuel tank has a brand new strainer on the bottom.

What to check next?

Thanks,

Sev

Any fuel leaks. Sounds like symptoms of a fuel leak and digesting air somewhere

Jake, there doesn't seem to be a fuel leak in the engine bay. The injectors don't leak at the points where they meet the braided fuel lines, nor where they meet the metal fuel lines. Granted it was raining today when I checked under the hood, so maybe I didn't see weeping there that was actually present.
Should I also check the lines going into and out of the fuel filter and pre-filter? How light of a leak could be causing this loss of power--a drip, drip, or a slight stream of fuel-type leak? Would it be something I could detect after a good 10 minutes of idling, while the car is parked? If so maybe I can dry all the fuel lines and connections with shop towels, and use a clean white paper towel on each fuel connection after it idles for a while to detect leaks

Could be some gunk in the tank is coming forward when you stop and getting in the Tank Screen.

Have at least 1/2 tank of Fuel and where the fuel hoses come off of the fender well swap their positions. That will have you bypassing the fuel tank screen and pulling fuel from a higher spot in the fuel tank.

After you do that you may need to use the hand primer to get the air out before actually driving.

If your problem goes away after that you need to deal with what is in the fuel tank.

If I do as you say and swap the fuel lines at the fender, can I actually drive like that, or just idle? If I can drive, how many miles can I drive?
I just replaced the fuel tank strainer with a new one prior to departing for a year, and the car was running strong at that time. Could diesel go bad in a year and develop something? Also, the fuel cap is keyed, and no one unlocked it while I was away, so it has that year old diesel in it. Let's just say there is gunk in the fuel tank, I have a Topsider which I use for oil changes. Could I just stick the tube into the fuel tank and suck out all the fuel?

Are these the two fuel lines I should swap?
<a target="_blank" href="http://imageshack.com/f/pnbNzbICj"><img src="http://imagizer.imageshack.us/v2/xq90/923/bNzbIC.jpg" border="0"></a>

I think so although it's hard to tell in a close up. I'd try running it on an alternate fuel source in a bottle in the engine compartment to see if it solves the problem. Is there anything blocking the air intake? Mouse nest?

Do you see air bubbles in your clear lines?
How old is your primer pump, it does look like the better push to pump type, not the unscrew pump retighten.
Also your location is not listed if it has been a rust belt car the fuel lines rust where they are supported which can leak air in.
Try running without the fuel cap on, if the fuel tank vent is clogged it exasperates any air leaks into the fuel system.
Did a critter set up shop in your air filter housing?
Just a few guesses.

You would be able to drive normally if it is the tank screen getting plugged is the issue. But because you are drawing fuel from a higher position you would run out of fuel sooner then the fuel gauge shows.


Personally I would only do the hose swap for testing. But if you really need to drive it keep the Fuel Tank full. Certainly do not go below 1/2 tank. Please note that the 1/2 tank is a guess of the minimum fuel needed to do the hose swap.

Yes but why are they already wet? That make me think your fuel hoses are leaking.


If the fat Cigar Hose is not long enough you will need to replace it with some 5/16" Fuel Hose that is long enough.

When I replaced the fuel pre-filter this morning, I disconnected one of those two hoses, and got fuel on both of the connection areas. I replaced the two hoses with each other just now and took it for a test drive. The car now runs properly. I don't get the problem with the sputtering anymore. The car doesn't hesitate going uphill anymore. So what does this mean?

By the way the 'fat cigar hose' you mention, is in fact decrepit and is cracking in a few places. Not leaking, but clearly needs to be replaced. I dried all hoses going into and out of the pre-filter, and into the two metal lines on the fender thoroughly with paper towels, and after taking it for a drive I tested for wetness with paper towels again and they were dry.

This is my backup to my backup car, and it's not needed for driving daily. Right now it's at 3/4 of a tank. If I keep it above 1/2 a tank, can I drive it continually without fear of damaging any systems?

When you say 'clear lines', which ones do you refer to? The only clear thing is the pre-filter, which is brand new. I didn't notice any bubbles in it. The primer pump was replaced with the newer push to pump style about four years ago. Since then I have only replaced the pre-filter twice, and only needed to pump it twice. Should it be replaced after a certain number of years, or is a 4 year old one sufficient? When I watched the Mercedes Source video on Youtube on replacing the pre-filter, he said that when you pump it, it will get harder and harder to pump, and you will hear some kind of squeaking noise from the injection pump after a certain point. When I pumped mine, it didn't get harder to pump, it had the same amount of pressure, and I didn't hear the squeaking noise he mentioned (I did this with the car off of course). I removed the air filter cover, and there is nothing in there. I didn't attempt to drive with the fuel cap removed yet.

There is no mouse nest in my air intake area. But that brings back bad memories. I had my mom's 1970 firebird parked in the driveway for many years untouched. When I popped the hood, nuts and rat crap were all over the intake manifold, and the wiring harness on the engine was eaten away, as well as the hood insulation. It cost me $500 in parts just to fire up the car again.
When you say alternate fuel source, do you mean such as when you put a bottle in the engine bay like when you are doing a diesel purge? Because I have the contraption that I made for that diesel purge which I read about on the diesel giant website, in the trunk of my car right now.

After reading back and forth posts, I'd be interested to see how the car runs off a separate fuel system. I'd rig up a can of diesel and secure it in the engine bay and drive it around and see if you have more power. The old fuel is likely to circulate through the fuel system before the new fuel. The newer fuel will sit at the top of the tank and old stuff will circulate through the pump and injectors first.

It may also be wise to run a diesel purge as well. Diesel does good bad with age, just like gas.