Hey guys,
My 1984 300d lately has been maxing out at about 60 mph. It feels fine around town (except on steep inclines), and will shift through all 4 gears. On the freeway, though, I can barely keep up with traffic. The turbo is working ( I can hear the blowoff valve, at least) and it seems like again all 4 gears are working (though honestly its a bit harder to tell on the freeway with traffic and hills, damn SoCal!). It kinda feels like the engine is starving - o2 sensor? Clogged fuel filter ?

Also the transmission fluid level is fine.

Thoughts ?



Thanks !!!

there is no O2 sensor,
the fuel filter will do that to a car. "spin on" filter behind the power steering pump should do it.
also inspect the clear prefilter, see if black flakes are in there... you could have an infestation in your fuel tank.
also, the alda line could be plugged, resulting in the turbo boost pressure not making it to the ALDA enrichment device on your IP.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

additionally, the accelerator linkage could be out of adjustment.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

If I were going to place a bet on it, I'd say fuel filters.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Air or fuel filter.

What, exactly, does a "blowoff" valve sound like?

There is a banjo bolt on the back side of the intake manifold, it has a clear hose attached to it, remove the banjo bolt and clean it out carbon build up often blocks the hose, resulting in no turbo.

__________________
82 500 SEL EURO - 88k - PARTING
84 500 SEC EURO - 200K
84 300 TD - 125K -Parted
85 300 SD- 178K
85 300 SD - 297K - Sold
88 190 E - 200K - Sold
89 560 SEC - 204K
90 350 SDL - 123K -Sold
91 300 SE - 94K- Sold
92 400E - 123K - Sold
93 300 TE - 200K - Sold
94 E420 - 78K - Sold
99 E320 Wagon - 160K

As everyone has already mentioned; it's always good to start with the basics like fuel and air filters, perhaps a Diesel Purge, and the banjo bolt and adjoining line. A valve adjustment may be in good order as well, but it sounds as if this power loss was somewhat abrupt, still, properly adjusted valves are always a good and important part of a 617's maintenance regime. I have run into the clogged banjo bolt problem on my, as well as my friend's, 617 turbo rigs, and every time I have had a tangible gain in performance and efficiency simply by cleaning the bolt and line...just be careful not to crack the old, and likely birttle, line that runs from the bolt.

These things may not solve the problem, but it's a good, and cheap, place to start.

So, explain this blow off valve. what, where is it.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

X2

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

... maybe he has a bad muffler, and he's hearing the wastegate opening?

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Well the pop-off valves that I am familiar with, on the street racer ricer turbos, make a loud, harsh, popping or death-rattle sound. There is no way any Mercedes diesel should be producing that sound from under the hood.

Three thoughts:

1. Check the U-shaped hose that runs from the air cleaner into the turbo inlet. If it has come really loose at the turbo it can make a sound SORT OF like a pop-off (my w116 SD did this once in a while, the turbo had shaft play and the sound I believe was the impeller blades lightly contacting the housing... with the hose properly placed you didn't really hear it, but when the hose came off it was clearly audible).

2. More likely he has a late '84 with the '85 EGR setup and is talking about the venting noise (the howl or sigh, I call it) that produces when you go on and off the pedal. (Well mine does, anyway.) Very similar to the sound made by some large diesel rigs in upshifts.

3. Serious leak in wastegate hose?

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I agree with vstech on the linkage ,the one easy way to check this is to see if the rod has play in it ,look at the linkage from the rod that assemblys from the main linkage to the firewall ,here youll find a hardened rubber pivot behind a plate that makes connection from their to the excellorator pedal,it rotts out over time giving the feeling of slow or low excelloration.I bought a car once with this issue and the people were explaining the same symptoms as yours except 35 mph.The bonjo bolt is another easy fix if thats not it ,it easy to get to ,located at the top left rear of the motor and connects at the rear of the intake ,youll need an open 13mm wrench and then clean the inner pieces of the bolt then replace ,the piece has a hose to the trannie,it always gets carboned up every 30k or less.A MB 617 COMMON upkeep and service advized listed item.

My '85 300D had a similar problem when I bought her three months ago. Like others have said, I would check:

1. Both fuel filters,
2. The fuel lines leading to the filters to make sure they are not twisted or kinked,
3. Both banjo bolts (at ALDA and behind the intake manifold).

On my car, there was a kink in the line leading to the pre-filter, and my banjo bolts were completely blocked. All the above are easy and cheap fixes, and very effective in improving power and performance. I can now reach 60 MPH with no problem, and there's plenty of power to accelerate further. A diesel purge will make a huge difference too.

Did the 84 cars get that ARV that the 85's have? I had problems with mine, it was making a squealing noise, so I just plugged with a BB.