1980 300d acceleration problem - PeachParts Mercedes-Benz Forum

mikesmitty · #1 02-14-2007, 07:20 PM

I just bought a 1980 300d and after driving it for a couple of days with no problems something happened. I had to slam on the brakes to avoid an accident and ever since then the car does not accelerate as it did before. It would barely make it up the hill to my house. That was yesterday, and this morning it took about ten tries to start. Once I got it started the acceleration problem was still there. Does anyone know what is causing this acceleration problem and how to fix it? Thanks.

Wodnek · #2 02-14-2007, 07:51 PM

See if when you stopped suddenly if something happened to your throttle linkage. On a non turbo, there really isnt much to go wrong.

toomany MBZ · #3 02-14-2007, 08:45 PM

Agree with Wodnek, something came disloged. Inspect under hood.

2.5Turbo · #4 02-14-2007, 08:51 PM

Could it have something to do with a brake dragging? When you're coasting, does it slow down quicker than it used to?

mikesmitty · #5 02-14-2007, 09:40 PM

Thank you for your responses.

Strange day with the car today. The glow plug light no longer comes on and when coldtakes about 10 tries to turnover. During one outing none of the windows or sunroof worked and the battery light remained on. Also the car had a had time shifting gears. After stopping and restarting all these problem were 'majically' fixed except for the lack of acceleration and low gear shift. I'm thinking a new fuel filter, and valve adjustment...........am I on the right track here?. Seperate note, there is a loud winding in the right front tire that sound like a flat. Could this be the bearing?

barry123400 · #6 02-14-2007, 10:00 PM

Sometimes all is not clear. You want to have a friend press the go pedal to the floor. Then see if you can manipulate the linkage at the injection pump further by hand to the stop. If you find you have more advance available adjust or repair the linkage.
I can think of little else you may have disturbed with the sudden stop as well. Most of the other problems you experienced and they self corrected could be an intermittent ground loss perhaps or something in the key switch for example. Observation over the next few days may give a better picture. Or just point you in a direction. You might also check in the archives. Also if you have a warm garage to work in a binge of cleaning ground connections and others might pay dividends.
I also hope someone on site will say it also happened to me and describe what they found. I might tend to wait for any additional clues at this point to occur. This sounds nasty but will probably turn out to be simple once found.

winmutt · #7 02-14-2007, 10:29 PM

Gear shifting is a vacuum problem pointing to the linkage area no doubt. For ****s and giggles jack each tire up and make sure the turn freely, if they dont (and I am betting they wont) pull the caliper off and make sure you can push the piston back in. Old car that has been sitting for a while IS going to have rusted calipers. I have yet to buy one that doesn't. If you have an assistant, have the, press the brake pedal why you are turning to ensure that the brakes are engaging and releasing properly. You may have inadvertantly engaged a caliper that had been frozen and now wont release. Check the hoses and consider just replacing them at the next pad change.

Mustang_man298 · #8 02-14-2007, 10:51 PM

Ok, it started with a hard stop, throttle got off and stayed that way, shortly after you began having a wiring and vacuum issue with the gp's and trans. So, I would check your engine mounts and arms, I have seen the bolt at the tip of the arms strip or rattle loose and fall out, engine looks good until you look for the missing bolt. I would suspect the bolt was probably loose or missing, and the hard stop caused the engine to shift forward, maybe it stayed that way or maybe it fell back into its place after it stressed the linkage and wiring/hoses. Have you noticed any unusual noises or vibrations when driving now? Possibly caused by the flex discs being stressed from a misaligned engine?

mikesmitty · #9 02-15-2007, 01:28 AM

There has been no rattle as far as or engine noise is concerned. I drove the car 75 miles on the freeway doing 70+ mph when first purchased with no problems. The only time I have experienced any lack of excelleration was after a hard brake. Maybe there is a vacuum issue. Any suggestions on where to find guidance for reapiar

kerry · #10 02-15-2007, 09:58 AM

Quote:

Originally Posted by mikesmitty

There has been no rattle as far as or engine noise is concerned. I drove the car 75 miles on the freeway doing 70+ mph when first purchased with no problems. The only time I have experienced any lack of excelleration was after a hard brake. Maybe there is a vacuum issue. Any suggestions on where to find guidance for reapiar

There's been a heck of a lot of guidance on this thread so far. Follow thru by checking out people's hypotheses. Checking whether a brake is dragging is pretty easy. Checking the throttle linkage is even easier. Changing the fuel filters is never a bad idea. Doesn't seem like a valve adjustment is the likely source of the problem. Do those things and then post the results back on this thread.

mikesmitty · #11 02-16-2007, 12:29 PM

I've adjusted the throttle linkage and discovered that the flat fuse was burned in half in the glow plug relay box. I'm looking for the part today and will post the final results.

Thanks again for the guidance

MattBelliveau · #12 02-16-2007, 12:38 PM

Quote:

Originally Posted by mikesmitty

I've adjusted the throttle linkage and discovered that the flat fuse was burned in half in the glow plug relay box. I'm looking for the part today and will post the final results.

Thanks again for the guidance

It seems that you have found the starting issue, however, the low power issue still remains, and I would assume that the two are seperate problems, as GP's only aid in starting. I would start with fresh filters, and a diesel purge. If that doesn't help, look to the tank strainer.

vstech · #13 02-16-2007, 12:49 PM

Do you have a floor jack?
jack up the front of the car, and spin each tire by hand. if they spin fine, (I also bet one won't) jack up the rear and repeat the procedure.
It is POSSIBLE, but unlikely that sudden stop would cause a fuel issue to arise.
John