I just bought a 86 350sdl, the problem is it takes for ever to get up to speed and if I reve it up to 3000rpm when it comes down it all most dies. Any thoughts would be great

There's no such car. If it's an 86, it would have to be a 300SDL. If it's a 350SDL, then it has to be a 1990 or 1991.

Replace both fuel filters as your very first step, even if they look perfectly clean. That procedure has been documented hundreds of times on the forum, but it amounts to replacing the clear plastic in-line filter in the obvious way (unscrew clamps, replace, clamp lines back on), removing the bolt from the top of the canister fuel filter near the power steering reservoir, discarding that filter, fill the replacement with clean fuel (not the used fuel from your old filter; it may have contaminants in it) before re-bolting, and then restart the engine. It will be hard to start because of air in the lines. The best strategy on your engine is to floor the accelerator during the entire process, and crank for 15-30 seconds at a time until the engine runs smoothly. Shouldn't take more than 4 tries, usually less.

Report back after the filters are changed if it has any effect... and let us know what the car actually is.

__________________


~Michael S.~
Past cars:

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


Current:

1987 300SDL

sure about that year?

Or that engine?

__________________
----Adam

1985 300SD 322,000

Well it is an 86 the trunk says 350sdl, but it might have come from another car

Is there an egr I need to disconect?

engine pics?
egr is pretty obvious the saucer connected to the flexpipe from the exhaust manifold connected to the intake manifold/crossover tube.
right above the tutbo I think.
pull the two 6mm bolts, build or buy a block off plate, and reassemble.

__________________
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!

Mulchman,

Let's not get ahead of ourselves. As Sherlock Holmes might say "eliminate the obvious."

1) Fuel filters - replace main/primary and pre-filter with quality OE units

2) Check the fuel filter screen at the bottom of the fuel tank, they can clog. You'll need a special socket (45 mm if I recall) to remove it after removing the fuel line fitting that is screwed into it

3) Check the clear polymide hoses to the ALDA at the top of the Injection Pump that leads to the overboost protection solenoid on the firewall - I'm betting oil and soot will fill this line when you check

4) Clean out the tube from the intake manifold that leads to the overboost protection solenoid. Drive the car and test

5) If you aren't seeing any change, you could have leaking hoses or leaky rubber connectors -bypass the overboost protection solenoid by pulling the line from the intake manifold and directly connecting to the ALDA at the top of the Injection Pump - Assuming the wastegate is moving and the turbo is spooling up and generating boost, the bypass of the line will allow the boost to be sensed at the ALDA and full fuel enrichment provided, which you are likely deficient in currently. Drive the car and determine if there has been improvement.

6) Check the vacuum hoses leading to the EGR and the wastegate actuator which is below the EGR. There are a number of connectors and the vacuum hose which leads to a tapping on the vacuum pump at the front of the crankcase (two lines, one thick line heading to brake booster, one thin line which is divided up for smaller vacuum consumers, one connector leads off to the wastegate on the turbo). Chances are these connectors near the turbo will be baked, the polymide brittle and likely leaking, or the actuator itself may be the fault, eliminate the tubes and connectors first. Drive the car and test.

7) Block the connectors on the top of the first vacuum transducer where the vacuum feed from the vacuum pump terminates (under the airbox). Run the vacuum tube directly to the wastegate actuator where it branches off from the vacuum pump. Drive the car and test.

Factory spec for an '86 300SDL is 0-60 in about 13 seconds. If you start getting into the 15-17 second range, you are in the ballpark, chalk the loss in acceleration to a drift in pump timing, injection pump delivery calibration, condition of chassis, wheel/tyre selection, etc. etc. If you are still in the 20-25 second range (or greater), then more diagnosis is called for.

Good luck and report back.

-bh

Fuel filter, classic symptom.

__________________

Gone to the dark side

- Jeff

Ok so I changed both fuel filters and oil also tried all the tests you guys told me but it is still slow. One thing I found is that the big hose for the air filter to the turbo was loose but still didn't fix it. Also my oil psi is at 1 1/2 bars when at idle, is that normal?

1.5 bars can be normal. Does it bounce around or stay steady?

Also does it peg at 3 bars when on the throttle?

It almost sounds like a defective ALDA, except for the fact that it almost dies when the revs come back down.

Has the ALDA's cap been removed by a PO?


edit: Not sure if you can see the top of the alda on a 603.

__________________
----Adam

1985 300SD 322,000

Sounds like an air intake problem (check for animals and nests), a fuel problem (filters, in-tank strainer, vent), or exhaust (no cat on the '91 but could still have a pinched pipe or something).

__________________

Gone to the dark side

- Jeff

It stays at 1 1/2 bar, and when driving it stays at 3. A I think it's my turbo it's not boosting up.

That is within spec.

__________________
----Adam

1985 300SD 322,000

I looked at the exhaust and I think I might have a cat it's right before the rear end, does this sound right?

Mulchman,

You have the correct replacement exhaust that was either replaced by the MBZ campaign free of charge, or via aftermarket purchase and installation. While an older unit might be clogged which will bog down the motor, exactly what did you check in terms of vacuum tubing so far? The lines between the air intake manifold and the ALDA, the lines to the turbo in particular. Also, did you get the socket to yank the fuel filter outlet screen? The goal is to isolate if you have typical fuel or air issues before moving to the less common causes.

-bh