major power loss - PeachParts Mercedes-Benz Forum

brownrice78 · #1 02-10-2016, 02:43 PM

Hey guys

Looking for your help on an issue I can't figure out. I have a 83 300 turbo and all of a sudden the car doesn't accelerate. Very noticeable at highway speeds. It idles ok, starts OK and moving around at 20-30 mph you don't notice it much. It really feels like the car is not receiving the enough fuel when the turbo. The car literally slows down going up hills.

I have already tried switching the fuel lines, cleaning out the alda lines, tested that the turbo has boost, car is shifting correctly. What's next to check??

Thanks.

shertex · #2 02-10-2016, 02:57 PM

Replace the fuel filters.

brownrice78 · #3 02-10-2016, 03:13 PM

I think I ruled that out by switching the fuel lines.

Jarod · #4 02-10-2016, 03:21 PM

Failed ALDA? sometimes the little diaphragm thing can burst and stick in no enrichment

barry12345 · #5 02-10-2016, 03:28 PM

Quote:

Originally Posted by brownrice78

I think I ruled that out by switching the fuel lines.

No I believe switching the lines does not bypass the main fuel filter. Even if you could do it. It should not be done.

On any diesel car the first thing you do with possible fuel supply issues suspect. Is change out the main fuel filter. The small one can obstruct as well of course.

shertex · #6 02-10-2016, 03:52 PM

x2 on changing filters as the first thing...it's so easy and cheap, and has to be done eventually anyway.

After you have done that and the problem persists, you might want to look at the tank strainer (although now that I think of it I guess that was eliminated by switching the lines).

yuke · #7 02-10-2016, 04:10 PM

Where did you check that tne turbo has boost? When I had same symtoms the nipple on the switch over valve was broke the line was off.

Mxfrank · #8 02-10-2016, 04:42 PM

Do this:

https://web.archive.org/web/20150511122612/http://dieselgiant.com/mercedesaldaboostsystemservi.htm

dkr · #9 02-10-2016, 04:51 PM

You should change the fuel filters. It takes 10 minutes and only costs about $15. Diesel purge would also be a good idea first.

Dkr.

Diesel911 · #10 02-10-2016, 05:06 PM

Quote:

Originally Posted by brownrice78

I think I ruled that out by switching the fuel lines.

Switching the Fuel Lines tells you that your Fuel Tank Screen is not plugged up. As the other Member said it does not tell you if your Fuel Filters are plugged or restricted.

How long should your Fuel Filters Last?
You could have just changed the Fuel Filters and drive to a Station and get a contaminated load of Fuel and in a few minutes your Filter can get plugged up. It just means your filters are doing their job.

Look at the Plastic Fuel Filter and if you see any black or grayish black gunk inside you could have an organism growing inside of your Fuel Tank. If that is the case then you will be plugging up a lot of fuel filters fast till you kill it.

brownrice78 · #11 02-10-2016, 05:08 PM

Quote:

Originally Posted by yuke

Where did you check that tne turbo has boost? When I had same symtoms the nipple on the switch over valve was broke the line was off.

I checked it at the rear of the manifold. There a bolt that come out and you can hook a Guage to it

brownrice78 · #12 02-10-2016, 05:09 PM

The plastic filter is only couple months old and doesn't look restricted.

brownrice78 · #13 02-10-2016, 05:15 PM

I took the plastic alda lines out completely and cleaned them. Switchover valve connections look go. Not sure if the Switchover valve works but it's plugged in. Does the alda piece that goes on top of injection pump go bad? If so, any symptoms. Just thinking outside the box

Diesel911 · #14 02-10-2016, 05:48 PM

A clogged Air Filter can also cause the low power symptoms.

In order to check if the ADLA is getting Pressure you need to T into the line between the ADLA and the Switchover Valve and hook on a pressure gauge that has at least 12-15 psi.

When there is no pressure or not sufficient pressure in the ADLA lines the ADLA will not allow more fuel. That means if the metal Diaphragms in the ADLA are cracked the ADLA will not hold the pressure that would allow more fuel.

While it is nice to know that the hose connections on the Switchover Valve are OK that cannot tell you if the Switchover Valve is plugged with gunk.

Disconnect the hose on the ADLA side of the Switchover Valve and connect another hose to it so you can blow through it. If you cannot blow through the Valve it is likely Plugged. or you could bypass the Switch Over Valve just for a test and connect directly to the ADLA.

shertex · #15 02-10-2016, 05:49 PM

Quote:

Originally Posted by brownrice78

The plastic filter is only couple months old and doesn't look restricted.

Then just change the canister filter.