Picked up a 300,000+ mile '93 300D, have some questions.

[atikovi]

The paint, body and interior are in quite decent condition, as nice as most with half these miles. Found some mechanical issues. It has a bit of a rough idle but smooths out when you step on the accelerator. On a short drive around the block I noticed it's quite slow to accelerate, no turbo kicking in and no turbo wooosh. Under the hood at idle I hear a kind of compressed air leak. Its like a puff puff sound 2 or 3 times per second. The transmission upshifts harshly, kinda snaps your head back when it shifts. And the tach is inoperative. Any first thoughts?

[muleears]

Here's my $.02. The slow speed acceleration possibly could be enhanced by an adjustment to the ALDA, made quite a difference on my 87. Harsh shifts are probably vacuum problems. Vacuum could also be the culprit with the lack of boost. I think the wastegate is vac. operated on this car. If its stuck open... no boost. Did you get to drive it enough to see if the turbo worked at all? I only rarely can hear my turbo anyway.

[TMAllison]

Puff/puff could = blow by.

[atikovi]

I only drove it down the street a half mile. At 20mph when I floor it nothing much happens. And that underhood noise sounds like a gas engine with a loose spark plug. Anyway I parked and won't get to it for a while anyway.

[compu_85]

The EDS system is probably pissed off. Probably rotten vacuum lines, same thing causing the trans to shift hard.

If the injectors are original they are probably shot, which would cause the poor idle along with even lower power.

-Jason

[jltcasper3]

The compressed air leak sound could possibly be a compression leak past the prechamber, i have had to different 2.5 turbos have a prchamber leak. Look around the injectors for the leak and if the plastic dirt protectors are still there they will start to melt a litte on the leaking ones, you might see a wet area around the injector, if it's realy bad u can feel it with your hand.

As for being slow, i bet your turbo is not producing boost, do a search on here for GXSR's pressure operated wastegate conversion, it's worth doing, i did it!! These cars are plaged with leaking vacume systems and the turbo wastegate works off of vacume. If u do this i would also delete the egr.

Also with 300000 miles, i would def check the timeing chain to see if it's streched (if it's really streched this throws off the timeing and can affect how it runs). Also have the injectors checked out.

Hope this helps

[jltcasper3]

After rereading ur post of this:
Its like a puff puff sound 2 or 3 times per second.

I am pretty sure it is a leaking prechamber. Check this out foresure.

[atikovi]

A short update. I went to where the car is parked to get it ready to drive the 30 miles home tomorrow and just to check under the hood again. I put in a freshly charged battery. The glow plug light doesn't seem to work so I just counted to five before cranking her up. Surprise surprise she started right up, just as if she was running yesterday! And the tach started to work again. Thats the good news.

The bad news is the engine is putting out quite a bit of smoke even after letting it warm up for 10 minutes. I didn't notice that when I bought the car. I hope I don't get pulled over by the police. Hopefully it will go away once it's fully warmed up. I looked closer for the puff puff sound and can see and feel with my hand, puffs of air coming from somewhere around the 3rd injector. Fuel is also leaking out around there as well. I'm not familiar with the anatomy of this engine but what do you make of this?

[wanative]

The Blue smoke may be your head gasket. I had to replace mine, with similiar indications. your oil usage will be real high. Blown at the front of the number 1 cylinder.

[Ian White]

The whoosh whoosh could also be an exhaust leak through a rotten piece of exhaust tubing.

[engatwork]

May be time to go through the engine.

[jltcasper3]

Originally Posted by atikovi

A short update. I went to where the car is parked to get it ready to drive the 30 miles home tomorrow and just to check under the hood again. I put in a freshly charged battery. The glow plug light doesn't seem to work so I just counted to five before cranking her up. Surprise surprise she started right up, just as if she was running yesterday! And the tach started to work again. Thats the good news.

The bad news is the engine is putting out quite a bit of smoke even after letting it warm up for 10 minutes. I didn't notice that when I bought the car. I hope I don't get pulled over by the police. Hopefully it will go away once it's fully warmed up. I looked closer for the puff puff sound and can see and feel with my hand, puffs of air coming from somewhere around the 3rd injector. Fuel is also leaking out around there as well. I'm not familiar with the anatomy of this engine but what do you make of this?

If u feel air around one of the injectors, i is most likley a precombustion chamber leak, yes u may get black fuely mixture blowing from it. To repair this u have to pull intake and then the glow glug and injector, then there are special tools to remove the locking ring and then to pull it out also. If the seats arn't damaged u can clean it and reinstall it and everything and it might be ok (my car is still running that way). If it's damaged, there is a cutting tool to repair the seats and then a shim to put the prechamber at the same hight in the cylinder.

Other things that cause a fuel leak around the injectors are the fuel leak off hoses between all the injectors. Just replace them with some new viton (biodiesel safe) hose.

For 300,000 miles, since u will most likley have the intake off for precahmber repair, i would replace all the glow plugs. Then u will want to fix the glow plug light problem, who knows what that might be. Also check timeing chain strech, if it's too far out, replace it. Have injectors pop tested and spray pattern checked, if bad replace the nozzels and have properly calibrated. Replace fuel filters if u havn't done that yet.

[i-osprey]

The lack of boost and hard shifting are a sign of a vacuum leak, probably in the infamous "rat's nest" near the air filter box.

[atikovi]

I drove it home today and what a white knuckle ride that was. It steers and brakes great but it has no power going up hills. On I95 I could barely keep 45mph on the slightest incline. It smoked a little but not as much as I expected seeing how much it did when cold. One thing I noticed is if you let off on the accelerator for a few seconds, when you get back on you have more power, as if it was bogging down before. Heck, I'm just glad I didn't need to get a tow to get it home. Actually I parked it at a shopping center down the road because I don't want to annoy the neighbors with the smoke screen it puts out when start it tomorrow. I might begin with a compression test to see if anything internal is broke. I'm thinking it could also be stale fuel. From the paperwork I see it hasen't been driven for the last 3 months. I see in the clear fuel filter that the diesel looks dark blue.

[Brandon_SLC]

Have you checked your oil level lately? If it is burning oil from a bad head gasket it can go through oil very quickly. I'd check it before starting the engine tomorrow, just in case.