Vesuvius is Sick! It just doesn't have any power... - PeachParts Mercedes-Benz Forum

mowoc · #1 05-04-2009, 08:38 PM

Well Vesuvius seems to be pretty sick. Here are the symptoms:

1. Very little power. The max Speed for the SDL is like 75 mph. If I am going up a hill it loses even that (it can slip down to 68 MPH on a steep hill).
2. It seems like it is starved for fuel when I reall push it. The car seems to "miss" like a car with bad spark plugs.
3. The car will only down shift when I hit the pedal to the floor - and then look out for the smoke!
4. I swear I smell diesel real strong when running on the interstate with the windows/sun roof open.

Here is what I have done -

1. I replaced the in line fuel filter.
2. I a have a brand new primary filter to put in. (Just where the heck is it on the car?).

A couple that ran through my mind:

1. Something in the tank?
2. Bad turbo?
3. I am being punished for something I did previously?

I would have no idea what else it could be. Any ideas would be appreciated.

tangofox007 · #2 05-04-2009, 10:09 PM

Quote:

Originally Posted by mowoc

1. I replaced the in line fuel filter.
2. I a have a brand new primary filter to put in. (Just where the heck is it on the car?).

The in-line filter is the primary filter.

Did you assume otherwise?

nickofoxford · #3 05-04-2009, 10:59 PM

How does the air filter look? How long did the power loss take to develop?

ah-kay · #4 05-04-2009, 11:05 PM

The only simple things I can think of are

1) Replace in line filter ( primary filter )
2) Replace spin on filter ( secondary filter )
3) Check for air leak on fuel line
4) Check for clog air filter and replace or run without it for a while to see whether it is the culprit.
5) Push compress air into the tank from the inline filter end to unclog the tank fuel filter. Replace if necessary.

If it still does not resolve it then it may be other issues.

Good luck.

nickofoxford · #5 05-04-2009, 11:07 PM

Quote:

Originally Posted by ah-kay

The only simple things I can think of are

1) Replace in line filter ( primary filter )
2) Replace spin on filter ( secondary filter )
3) Check for air leak on fuel line
4) Check for clog air filter and replace or run without it for a while to see whether it is the culprit.
5) Push compress air into the tank from the inline filter end to unclog the tank fuel filter. Replace if necessary.

If it still does not resolve it then it may be other issues.

Good luck.

ahh i knew the tank strainer was going to pop up eventually! simple job, just be ready to get soaked in fuel.

mowoc · #6 05-04-2009, 11:16 PM

Quote:

Originally Posted by tangofox007

The in-line filter is the primary filter.

Did you assume otherwise?

I afraid I did. When I went to NAPA to see if that had the spin on filter they called it the primary.

Where is this filter mounted on the car? I don't see it right off, but I am not sure where to look (I suppose I could follow the fuel line).

The power loss seemed to happen while I was down in Georgia. I am not sure how long it took, but I noticed it a few weeks ago. I will check the air filter tonight/tomorrow morning and see whats up.

I was fearful of the tank filter as I thought about that too. The idea of blowing compressed air into the line is intriguing though. Would I just undo the feeder end of the inline and blow a small amount of compressed air back into the line? If so, how much and for how long?

EDIT: I just pulled the air filter - it looks a bit dirty (lots of little stuff in it). I don't know if it is dirty enough to cause the issue, but I will get a new one tomorrow just to be safe.

ah-kay · #7 05-05-2009, 01:24 AM

The spin on filter is right behind the top radiator hose. If you replace it, make sure you fill the new filter with diesel first. Otherwise you need to crank the motor for a long long time to start as there is no manual priming pump on the SDL.

I really doubt it is the tank filter ( strainer ) but it is worth a try with compress air. Open the filler cap and put compressor air in for, say 2 minutes. It really does not matter how long as nothing will be damaged.

You don't happen to be running biodiesel or WVO, do you? Biodiesel or WVO tends to etch up all the crap from inside the tank after a while and clog the primary and 2nd filters.

Good luck.

Abadjay · #8 05-05-2009, 01:50 AM

I experienced these symptoms as well...and it turned out that an vacuum line was disconnected from the intake to the ALDA. BIG DIFFERENCE once I got it connected again. In fact I've only taped it back up...no serious adhesive....maybe I have a pic of that somewhere...

colincoon · #9 05-05-2009, 09:45 AM

Replace the primer pump, I had the exact same thing happen to me. You probably smell diesel because the primer pump is most likely leaking it everywhere. Check the motor mount below it and see if it's wet (or if anything is wet for that matter).

This is assuming you have the old style primer pump of course.

LUVMBDiesels · #10 05-05-2009, 10:52 AM

Remember there is no primer pump on the OM603 engine.

1) Check the rubber fuel lines. The ones that run from the plastic inline filter could be breaking down and letting air into the fuel.

2) Remove the boost signal lines (clear tubes) from the ALDA (Square box on top of the Injection Pump or IP - the thing the metal tubes run out of) and make sure that they are clean. Spray some carb cleaner into the lines and into the black box mounted on the fender that the lines connect to (overboost switchover valve) Also poke a pipe cleaner through the nipple where the boost tube connects to the intake manifold.

3) Try running a piece of the clean plastic tubing directly from the intake manifold to the ALDA to see if that helps the power.

4) Check out the black rubber 'Y's that connect the vaccum signal to the boost signal heading to the ALDA. they could break down and cause the boost pressure to leak. I jut plugged the vacuum line with a golf tee and connected the boost line to the ALDA

Good luck!

mowoc · #11 05-05-2009, 11:01 AM

Thanks for all the replies!

I did not convert the car to WVO, I am running straight diesel.

I will mess with all of this and report back later today.

mowoc · #12 05-05-2009, 11:42 AM

OK, i just went over the ALDA stuff and the fuel lines.

The fuel lines look reasonable new. I will replace the primary filter one more time to be safe, but I don't think it is them. I do have some 3/8 inch line here if you think I should replace it just to be on the safe side.

The ALDA lines are old, but I cannot see any leaks. That being said, it might be worth while changing out the lines to see what happens. Where do I find the vacuum line parts?

One other thought, could it be the overboost switch over valve? I think I found it, it is the box on the driver's side with the vacuum lines and electrical lines coming out of it, right?

I am off to NAPA to get the air filter and primary filter.

EDIT: How the heck do you get the secondary fuel filter off? I can't see how you would get a wrench on that filter.....

ah-kay · #13 05-05-2009, 12:02 PM

Quote:

Originally Posted by mowoc

EDIT: How the heck do you get the secondary fuel filter off? I can't see how you would get a wrench on that filter.....

You undo the banjo nut on top. You need a 17 or 19 mm spanner. I cannot remember exactly.

LUVMBDiesels · #14 05-05-2009, 12:13 PM

Quote:

Originally Posted by mowoc

OK, i just went over the ALDA stuff and the fuel lines.

The fuel lines look reasonable new. I will replace the primary filter one more time to be safe, but I don't think it is them. I do have some 3/8 inch line here if you think I should replace it just to be on the safe side.

The ALDA lines are old, but I cannot see any leaks. That being said, it might be worth while changing out the lines to see what happens. Where do I find the vacuum line parts?

One other thought, could it be the overboost switch over valve? I think I found it, it is the box on the driver's side with the vacuum lines and electrical lines coming out of it, right?

I am off to NAPA to get the air filter and primary filter.

EDIT: How the heck do you get the secondary fuel filter off? I can't see how you would get a wrench on that filter.....

The box you mentioned is the over boost switchover valve. the lines coming out of it are boost signal lines not vacuum. Since the car has separate boost and vacuum systems you really need to distinguish between them.
Try bypassing the over boost switch by running a tube directly from the ALDA to the intake. If the power comes back then the switch is blocked and can be cleaned by spraying carb cleaner into the boost line ports.

The black rubber 'Y' connectors are what go bad and start leaking so if you are heading to NAPA, get replacements for those before you replace the plastic tubing.

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