At my wit's end ( 300D suddenly doesn't want to start ) - PeachParts Mercedes-Benz Forum

skalie · #1 04-05-2013, 12:00 PM

This would be a OM617.

She 's been regular as clockwork all winter, had replaced the fuel lines, filters and glow plugs, starting up in all temperatures no problem.

Then the other morning, I almost flattened a battery trying to get her to go, nothing.

Checked full, injectors out of the block, but still connected to the injection pump, squirt x 5.

Glow plugs, could see their glow reflected in the tappet cover when I had the injectors out.

Tappets, just did them, one exhaust was all the way down, 0.25, and they were all way too tight, but still.

Why no start, all of a sudden.

Contamination of the fuel is the only thing I haven't ruled out yet, as far as air/fuel/glow is concerned. Maybe someone spiked her with something ( no locking fuel cap ).

Injection pump lost it's timing somehow ?

Compression suddenly isn't enough, highly unlikely, but will check the compression next week anyway.

Tow start on the horizon, but what could have possible gone wrong ?

mach4 · #2 04-05-2013, 12:11 PM

Quote:

Originally Posted by skalie

Contamination of the fuel is the only thing I haven't ruled out yet, as far as air/fuel/glow is concerned. Maybe someone spiked her with something ( no locking fuel cap ).

Probably a low probability, but easy to check. Get some fresh diesel and set up like you were going to do a diesel purge however do not allow the return fuel to go back into the container. Catch it in another container. Go ahead and try to start. After a few minutes, you can put the return line into the container and continue to try to start. You'll want enough to flush the secondary fuel filter (or replace that if not done recently)

This procedure will not only test for contamination, but also tank strainer clogging, primary fuel filter clogging etc.

Zacharias · #3 04-05-2013, 12:12 PM

Thoughts:

1. If I understand correctly, you mean that you JUST did the valves before this problem started? Are you sure you didn't mix up exhaust vs. intake when adjusting the clearances? Lots of people have done that.

2. Check for blockage in the air intake.

3. Seeing a reflected glow doesn't tell you that the glowplugs are glowing hot enough. How old are they?

skalie · #4 04-05-2013, 12:23 PM

Quote:

Originally Posted by Zacharias

Thoughts:

1. If I understand correctly, you mean that you JUST did the valves before this problem started? Are you sure you didn't mix up exhaust vs. intake when adjusting the clearances? Lots of people have done that.

...no, I whipped the tappet cover off while troubleshooting, and thought I may as well do the valves while I was there.

Quote:

Originally Posted by Zacharias

Thoughts:
2. Check for blockage in the air intake.

Check, disconnected it.

Quote:

Originally Posted by Zacharias

Thoughts:

3. Seeing a reflected glow doesn't tell you that the glowplugs are glowing hot enough. How old are they?

New, had recently upgraded to "pencil" types, checked three out of the engine, and looked into the holes to see them stoking away.

... and, yep, mach4, that was my plan of action regarding checking for contaminated fuel.

Stretch · #5 04-05-2013, 01:29 PM

Did you fill up at a different place from normal recently? (If so fuel seems more and more likely)

skalie · #6 04-05-2013, 02:37 PM

Quote:

Originally Posted by Stretch

Did you fill up at a different place from normal recently? (If so fuel seems more and more likely)

... as it goes, the last time I tanked was at "card only" place in Hilversum. Never tanked there before, just happened to be a cheap place there just before I got on the highway.

Hmmmmmmmmmmmmmmmmmm.

Yep, I'll be eliminating the fuel possibility as soon as possible.

kerry · #7 04-05-2013, 03:15 PM

Check the fuse on the glowplugs and check for voltage at the plugs. 99% of no-start conditions are glowplug related.

vstech · #8 04-05-2013, 05:58 PM

Quote:

Originally Posted by kerry

Check the fuse on the glowplugs and check for voltage at the plugs. 99% of no-start conditions are glowplug related.

... well... 60% at least... Fuel filter is very often the case...

skalie · #9 04-06-2013, 09:10 AM

Quote:

Originally Posted by kerry

Check the fuse on the glowplugs and check for voltage at the plugs. 99% of no-start conditions are glowplug related.

Going to have to assume that you didn't read any of this thread before replying.

.... just ran down two more batteries trying to start the thing off a siphon feed with clean diesel.

Compression test is the next step, I guess ( yes, I have already been pricing secondhand engines ) and a tow start.

Although why the compression would suddenly disappear on a perfectly * functioning engine is beyond me.

* Ok, black smoke, burning oil, but no starting problems whatsoever.

Mölyapina · #10 04-06-2013, 10:54 AM

Quote:

Originally Posted by skalie

Going to have to assume that you didn't read any of this thread before replying.

.... just ran down two more batteries trying to start the thing off a siphon feed with clean diesel.

Compression test is the next step, I guess ( yes, I have already been pricing secondhand engines ) and a tow start.

Although why the compression would suddenly disappear on a perfectly * functioning engine is beyond me.

* Ok, black smoke, burning oil, but no starting problems whatsoever.

If it was burning lots of oil, the rings may be worn out.

Zacharias · #11 04-06-2013, 11:16 AM

I know you said you checked for fuel at the injectors previously... but are you seeing/smelling unburned fuel coming out the exhaust now?

With cranking it for that long, I would expect to see clouds of it out the back end....

Have you tried having someone work the primer pump as you crank?

Did you by any chance add anything to the fuel at the last fillup, fuel system cleaner, etc.?

skalie · #12 04-06-2013, 11:48 AM

Quote:

Originally Posted by Zacharias

I know you said you checked for fuel at the injectors previously... but are you seeing/smelling unburned fuel coming out the exhaust now?

No discernible smoke at all.

Quote:

Originally Posted by Zacharias

Have you tried having someone work the primer pump as you crank?

Good tip, thanks.

Quote:

Originally Posted by Zacharias

Did you by any chance add anything to the fuel at the last fillup, fuel system cleaner, etc.?

Only after the problem occurred, "Wynn Diesel +Plus+ treatment".

skalie · #13 04-06-2013, 11:49 AM

Quote:

Originally Posted by Jooseppi Luna

If it was burning lots of oil, the rings may be worn out.

... hopefully the tow start will get me going and I'll have smoke colour to help my prognosis of what the heck is going on here.

Stretch · #14 04-06-2013, 12:01 PM

Generally speaking engines don't suddenly die like this unless there's something obvious like drastic oil loss / vacuum pump exploding its bits into the timing chain etc etc etc

Have you checked daft things like

1) the accelerator linkage?
2) fast idle knob / stop lever stuck / messing you about?
3) tried starting the car with the vacuum shutdown pipe disconnected? (Don't forget to put it back after starting!)

skalie · #15 04-06-2013, 12:23 PM

Quote:

Originally Posted by Stretch

Generally speaking engines don't suddenly die like this unless there's something obvious like drastic oil loss / vacuum pump exploding its bits into the timing chain etc etc etc

Have you checked daft things like

1) the accelerator linkage?
2) fast idle knob / stop lever stuck / messing you about?
3) tried starting the car with the vacuum shutdown pipe disconnected? (Don't forget to put it back after starting!)

Yes, yes and yes.

Was really hoping that it would have been something simple like that, but the injectors sprayed on to the motor when I had them externally connected, which sort of rules out those factors.

The troubleshooting on this one has been a succession of "damn, that's working", "damn, that's working as well".