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-   -   81' 300SD starts and then dies after a few seconds (https://mercedesforum.com/forum/diesel-discussions-33/81-300sd-starts-then-dies-after-few-seconds-35923/)

xkeithx 04-07-2009 11:01 AM

81' 300SD starts and then dies after a few seconds
 
ive been running it on veggie oil for a little while with absolutely no problems. however yesterday i noticed some smoke from the exhaust while on wvo and its never had smoke before. anyways i got home, purged the lines as usual and accidentally ran out of fuel so i did get some air in the lines.

currently my diesel tank is out of the car and im just using a half gallon container as my diesel tank to warm up the engine, then switch to the veg tank in the trunk. and i have clear fuel lines so i can see whats going on and where the air is.

i pumped the priming pump to remove all the air from the lines, and could see that diesel was coming from the tank, to the ip, and was being returned back to the tank.

cranked it over and it started just fine, it will idle for maybe 2 or 3 seconds and then it just shuts down. i can also rev the engine up but even with the gas pedal to the floor the rpms start dropping and the engine stalls after about 5 seconds.

i checked all vacuum lines and everything's connected like it should be. its very odd that it would just all of a sudden not start on me like this. any suggestions?

cycleboy 04-07-2009 03:37 PM

Fuel filters.

xkeithx 04-07-2009 06:37 PM

just put new ones in today. its still having the same problem. heres a couple videos i shot of the problem in action

http://www.youtube.com/watch?v=8jE78xkQJAA
http://www.youtube.com/watch?v=d_NSfATGWMM

jimishadow 04-08-2009 04:13 PM

chec screen in fuel tank

cycleboy 04-09-2009 05:57 PM

It's not getting fuel. Pull the injectors and check them individually.

vlado 04-09-2009 11:57 PM

try disconecting your vacuum line for shutoff switch on pump and try.maybe your ignition switch went bad that lets vacuum pass thru and shut off your engine. good luck

xkeithx 04-11-2009 01:06 AM

got it started, i took off the oil cap and it held an idle. i was able to drive the car home with the cap on loose but naturally there was a ton of oil all over the engine by the time i made it home. i took off the cap once i parked with the engine still running and there was a ton of blowby. also if i pulled on the throttle linkage a big white cloud came from the exhaust. with the engine warmed up i replaced the oil cap and the engine continued to run.

still not sure of the original cause of this problem, however. i plan on driving the car a little bit tomorrow to see if i can replicate the problem and try to narrow it down. ive replaced the breather hose from the air intake to the valve cover, my old one was cracked and taped back together but i dont believe it was the cause of the issue i was having.

cycleboy 04-11-2009 09:03 AM

Have you checked the oil level? Is it over-filled?

Although it really sounds like when you pumped the lines you perhaps still didn't have them completely full of diesel and now it's just run through and you're getting fuel.

wrecker 04-11-2009 01:55 PM

hello
i would suspect that you are either having a worn fuel pump due to using old wegy oil or slight crack on the pump that draws air inside system....

xkeithx 04-12-2009 10:38 AM

the oil level is right in the middle of the two notches. i got all the fuel out, im just concerned that i will get stranded somewhere if this issue comes back. yesterday i drove about 40 miles to the boneyard and back to pick up some parts, and had no issues. no smoke and it seems to be running great now! its just very strange that i couldnt get it started due to too much pressure in the engine, and had to drive home with the oil cap cracked to relieve the pressure.


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