300D woes... - PeachParts Mercedes-Benz Forum

jfman · #1 05-15-2006, 02:26 PM

Ok I started driving the 300D today (the clean one) It is much much slower than my parts car. Especialy on take off and it hesitates when I take off. They are both identical cars same year everything. I also noticed a knocking noise from it that was not there in my parts car. Now the weird part about that is that it will do it and stop doing it, do it again, etc... it's intermitent. I have never seen a car do that because it's like an ON/OFF switch. it might stop doing it for a couple minutes and then start doing it again. Somtimes it does it at idle, other times it does only when I rev it up and other times it doesnt do it at all. What could it be ?

Also, since I'm mentaly preparing for the worse: do you guyz have a DIY thread on swaping the motor ?

I'm pretty good with a wrench but it's always a good idea to get some tips from people taht have done it before you.

Maroon 300D · #2 05-15-2006, 02:32 PM

I don't know about the knocking, but my car was much faster on take off after I adjusted the rack dampener pin. If your engine has a lot of vibration at idle this could also be a sign that it needs adjusting or is broken.

If you haven't looked at this yet it's very easy to do, especially if you are handy enough to be contemplating a DIY engine swap!

jfman · #3 05-15-2006, 02:37 PM

Well it does shake a little more than my parts car at idle. However if something is seriously wrong with the motor itself, spening time swaping this part would be pointless.

It's not that big of a deal since I have the parts car but I would like to avoid spending another weekend working on it if I can.

The sounds seems to be like a light rod knock or maybe a valve tap... It's hard for me to guess because I am so new to MB's and diesels as well.

Volvo Diesel · #4 05-15-2006, 04:35 PM

Quote:

Originally Posted by jfman

I also noticed a knocking noise from it that was not there in my parts car. Now the weird part about that is that it will do it and stop doing it, do it again, etc... it's intermitent.

Dirty or worn injectors will sometimes cause an intermittent tapping sound...you can do a search on "nailing" and get lots of information about this. Also, take a look at DieselGiant's website for the pictorals on both the diesel purge procedure and the injector nozzle replacement. I'd start by purging the car, or simply switching the injectors over as a set from the 'organ donor' and seeing if the noise persists...dirty/worn injectors could also be contributing to the low power, rough idle, and smoking problems. In my experience, a rod knock isn't intermittent, although these motors make enough noise that sometimes it's hard to tell whether a sound is consistent or not. At any rate, best of luck!

-Chris

jfman · #5 05-15-2006, 05:11 PM

There is a lot of things I will learn working on this car.

You are right about thee knocking. It doesnt make sense that it would stop and come back like that.

Biodiesel300TD · #6 05-15-2006, 05:16 PM

The Knocking-You might also try adjusting the valves. I believe DieselGiant has a DIY on that as well. Engine shaking could be caused by worn out engine mounts and/or engine shocks, or a worn out rack damper pin.
The lack of accerleration-You might also look into adjusting the ALDA for a little more acceleration from the line as well.

winmutt · #7 05-15-2006, 05:19 PM

Quote:

Originally Posted by jfman

There is a lot of things I will learn working on this car.

You are right about thee knocking. It doesnt make sense that it would stop and come back like that.

It could be something as simple as air getting in the lines as well.. Check the prefilter for air coming in as well as the return lines from the injectors.

#8 05-15-2006, 05:26 PM

Quote:

Originally Posted by winmutt

It could be something as simple as air getting in the lines as well.. Check the prefilter for air coming in as well as the return lines from the injectors.

Check the cigar line, that odd shaped line coming from the steel fuel line going into the IP. It gets rotted with age. Remove it and plug one end an blow on the other. Will tell you if it is bad.
Also check the pressure line coming from the very back of the intake manifold and going to the crossoever switch and then on to the top of the IP. That line tends to get gooped up at the manifold end. Needs to be clear to signal the IP to dump more fuel when the turbo spools up.

RAYMOND485 · #9 05-15-2006, 05:46 PM

1984 300d Turbo 138k
Order 5 Bosio Nozzles For Fuel Injectors 30 X 5 =150 From Diesel Giant.com Improve Power And They Have The 5 Heat Washer Also $2.00ea =10.00 2hrs Diy Done Torque 50 Pds And New Fuel Return
Lines Also Add A Water Fuel Filter **************.com $110.00 Diy 1 Hr They Have Other Kits

jfman · #10 05-15-2006, 05:55 PM

Another thing I should add is that the car has been sitting for at least 5-6 months now. It's still the old fuel in there.

jfman · #11 05-15-2006, 06:16 PM

Ok.. This cant be good

There is a filter left of the brake booster but it's not pluged to anything. Maybe it goes to this thing that is bolted onto the firewal ? what is it for ?

I also removed the banjo bolt line. It's pretty oily on the intake side but not clogged at all.

85chedeng300D · #12 05-15-2006, 09:48 PM

that line with a clear in-line filter is an ATM vent that should be left unplugged and goes through the firewall to the inside cabin. about the open nipple on tthe switchover valve, there should be another one line from the main vacuum hose nipple of the vacuum pump hose. if i'm not wrong it should be a black with a green stripe hose.

85chedeng300D · #13 05-15-2006, 09:52 PM

Quote:

Originally Posted by 85chedeng300D

that line with a clear in-line filter is an ATM vent that should be left unplugged and goes through the firewall to the inside cabin. about the open nipple on tthe switchover valve, there should be another one line from the main vacuum hose nipple of the vacuum pump hose. if i'm not wrong it should be a black with a green stripe hose.

oops! sorry! my bad! I just checked back on the attached photo, and realized that on the switchover valve nipple, it should have a clear line that goes to of from either the banjo bolt of the intake manifold or the ALDA in top of the Injection Pump

Maroon 300D · #14 05-16-2006, 12:28 AM

jfman - I see you've got an '85. Do you know if it's a CA car or not? I believe some of the vacuum connections are different. The vacuum diagrams phantoms posted on this site might help you out.

And by the way, what's an ATM vent? I'm not familiar with that so if someone could explain, that would be great!

Samuel M. Ross · #15 05-16-2006, 01:34 AM

if you don't already have one, go to:
http://www.peterschmid.com/
and see if you can find the engine vacuum diagram for your cars...
look at "Vacuum Schematics" link in the left sidebar, then your model
year and engine. You will also need to know if it was originally
purchased in California.
The fuel filters on vacuum lines is most likely an old mechanic's trick to
keep debris out of the vacuum system or acts as a "tell-tale" to let
you know when the engine shut-down vacuum switch has vailed and contaminating the vacuum system with oil from the IP.
I hope this helps.
Sam // Novato, CA