1997 E300D advise on acceleration from a stop - PeachParts Mercedes-Benz Forum

Pabster · #1 05-03-2012, 10:52 PM

I am a lucky guy who picked up a 1997 E300D at 190K miles in decent condition and I want to get it running great again. I think the other owner just didn't want to get dirty and he had two other MB's to worry about.

I want to trouble shoot the acceleration mystery and here are the clues:

A) Engine revs nicely in Neutral and Park and it appears very responsive when the pedal is pushed. Push the pedal a little and it revs.

B) When the car is in drive and at a stop, it doesn't respond quickly with the pedal when its time to go. Thus the immediate acceleration is dog slow, pokey or doesn't want to go. Once you get some momentum from the start and press the accelerator deeper, it gets going and drives well.

C) Once it get going, it drives fine and it drive fine at highway speeds. Again, when you slow to a stop in Drive, its B all over again. Some stops and go are a little better than others, but all in the category of under performing and a potential traffic hazard.

After much reading on PeachParts.com I thought these clues would give the pro's some hints to point me in the right direction to toubleshoot this issue.

Thanks,

Pabster

biopete · #2 05-03-2012, 11:52 PM

Does it help if you downshift it , start off in second and then shift at 2500 or 3000 rpms? It could be it is shifting too early. I have one doing that. Not sure why its doing it though. Its like the bowden cable does nothing at all.

Jeremy5848 · #3 05-04-2012, 12:09 AM

I suppose it all depends on an individual's previous experience and definition of "dog slow." I have found with both of my OM606NA machines that they are very slow off of the line (a) in general, being normally aspirated engines and (b) if you give only a small amount of throttle.

As an experiment, try flooring the accelerator from a standing start and see if the response isn't better.

As a second test, drive the car for a few days with a heavy foot, allowing the engine to rev above 4000 RPM before shifting to the next gear. That may clean it out a little (this is sometimes called an "Italian tune-up"). Mercedes owners are sometimes little old ladies who drive around slowly, allowing carbon to build up in the engine. The OM606 has a 5400 RPM limit and, with its double-overhead cams, likes and needs to rev if you want to get any power out of it.

Finally, have you disabled the EGR valve and cleaned out the intakes? At 190000 miles they will be filthy.

Jeremy

Pabster · #4 05-04-2012, 01:32 AM

I will try the Italian "tune up" after I change the engine mounts, filters, and fluids this week-end. The previous owner had new glow plugs put in in less than 5K miles ago. Then I will disable the ERG and check out the manifold inlet and clean it very carefully. Next will be the tank fuel filter and all the vacuum components, VCV, Vacuum sensor line.

Then its off to fix the A/C, with the likely suspect being the compressor or clutch plate, sensors...etc.

Hopefully, I will get this baby purring soon and then I can move on to the WVO/biodiesel project.

Staying busy and thank you for the hints and suggestions. Please keep them coming!

Pabster

spark3542 · #5 05-04-2012, 08:24 AM

97 has a flapper on the crossover pipe and a flapper on the manifold. The vacuum lines to these flapper actuators crack, and the wiring to the position sensors at the flapper also corrode. Usually either of those situations will trigger an engine code, but they will most definitely trigger reduced power.

Delete the EGR, there are threads here on how to do it without angering the computer. Small air filter and a minor amount of backyard "fabricating" needed.

Clean air filter and italian tune up. There, you've maximized the lung capacity.

buckstersdad · #6 05-04-2012, 09:59 AM

If it were mine I would probably be scratching my head and then realizing I had the transmission selector switch in the "W" position and always starting off in 2nd.

Hope its something simple like that.

Pabster · #7 05-07-2012, 10:02 PM

Well, it took a little time to get to know the car. What is happening is that after the engine warms up and I come to a stop, the car seems to stay in 4th gear on the start and sort of putters until I press the accelerator deeply and the transmission shifts to 1st gear immediately and gets going. This doesn't happen all the time, just some of the time.

I think after my big tune up and by passing the ERG, this may clear things up.

New question for the pro's. I changed the engine mounts and that helped dampen the effect of the engine. But the car still shakes a little to the thumping of the engine at a stop when the transmission is in Drive or Neutral. I know the mounts were put on right, so I am guessing the idle is too low and needs to be bumped up to a rev amount that provides better harmonics for the engine.

I will address this during the week-end and see if it helps. Ultimately, its in the big tune up picture to replace the fuel lines, tank screen, and clean the tank. I am sure that one will be fun!

Pabster

Aquaticedge · #8 05-07-2012, 10:11 PM

did you replace the trans mount too?

Pabster · #9 05-08-2012, 06:23 PM

No, but I suspect I didn't do the engine mounts correctly. At idle, the engine thumps back and forth and I can see it go back and forth as if the mounts are not doing their job. This weekend, I will have a spotter to help me this time and I suspect they just need to be readjusted, tightened, or repositioned.

I will replace the transmission mount as well.

Thanks,

Pabster

Pabster · #10 05-10-2012, 09:29 PM

Readjusted the driver side engine mount to fit properly. The mount fitting was not in the grove, but next to it. After fixing, the car didn't shake as much, but there are still more check points to work. Thanks to my spotter, little Ms. 13 year old

I was able to get this done quickly and with confidence.

For the 1997 E300D, its good to get a top side spotter when its time to put the driver side engine mount on.

Pabster

Jeremy5848 · #11 05-10-2012, 11:14 PM

I forgot to put the drip shield on the driver's side mount (thought it was shipping material) and had to take it apart again. Don't recall having problems getting the mount in the right place but I did need an extremely long set of 3/8" extensions to reach down through the intake manifold and tighten the upper bolt.

Jeremy

Pabster · #12 05-12-2012, 11:10 AM

For my car, I used a 17MM box wrench for the top bolts to do the initial loosening and final tightening of bolts on both engine mounts. This was a handy tool that slipped under the heat shield on the passenger side and was easy to use on the driver side. I didn't have to remove any other parts to work on the mounts.

I tightned the engine mounts from the bottom of the car and use a 3/8 socket wrench to do easy busy work of screwing in the top bolt while my other hand held the driver's side mount in place.

When starting up the car, its fairly smooth with a little to minor vibration. After the car warms up and I see the oil at 80 degrees, the car does vibrate/shake a little with the thumping of the engine. The suspects are the injectors needing some servicing/replacing. Does this sound familiar to anyone?

Everything is getting reviewed and serviced one by one.

Pabster

Pabster · #13 06-11-2012, 10:01 PM

I did some work to chase down the air vacuum in the engine which got the engine thumping and shaking the car.

a) replaced all fuel lines in engine area.
b) replaced pre fuel filter and fuel filter.
c) fabricated fulltime EGR blocking plate.
d) cleaned out crossover pipe, intake manifold, replaced oil breather pipes.
e) serviced the delivery valves (replaced washer and o ring) follow instruction to the T on this one. I didn't tighten the nipples enough and fuel was spitting out of it on my test drive.

After a little panic, I got back into it and tightend them up. After tightening them up, the car drove as smooth and responsive as could be and there was no fuel leaking anywhere. Additionally, the engine doesn't shake. It drove like a Mercedes should drive and what a difference! The car was so responsive from the stop and shifted so much smoother.

After doing all this work the first time, I did have to start the car about 12 times to get the fuel pressure back up and the engine running. I guess if I tightened the nipples properly, perhaps it would have taken a few less starts. I only cranked the engine for 8-10 seconds a pop and rested the car after each start.

If the guy who sold me this knew how well it drove after this DIY service fix, he would be begging for it back and paying me a big premium. However, this one is a keeper and a promising 400K+ miler in my hands.

I will just keep taking good care of it. Thanks Phil and Roy for all your assistance. Peachparts is the best!

Pabster