1985 MB 300DT problems over problems - PeachParts Mercedes-Benz Forum

siral3x · #1 02-08-2008, 09:48 PM

I put over 12k miles now on the car since I bought it and it's due again for a valve adj. I just replaced some crappy Autolite glow plugs with NEW BOSCH and WOW ...what an improvement!
Now my main problem is this: I let the car glow for 20 sec and it fires right up with no issues at 20-35F weather. It runs nice and smooth for about 5 more sec after I start it and then it starts too MISS, shake, and idle loops erratically, eventualy stalls. It seems like the engine is not receiving enough fuel OR maibe to much??? I glow again, car starts fine..KEEP my FOOT on the throttle and keep it at around 1k rpm for 30-40 sec and then NO more shaking, looping, stalling! During the start up proces I can see on the white snow black ash like deposits comming out of my exhaust, BUT no smoke really..maybe a little bit.
1. How do I adjust my idle speed to 750rpm-800rpm??
2. I want to change my inj nozzles, what is the correct part number for my injectors and WHAT type and model the 85 DT is equipped with??
3. I have a set x5 (060) KCA30S35/4 241 135bar injectors that I want to rebuilt but I don't know if they came out of a TURBO OM617 or if they would work on my 1985 model OM617Turbo. Any imput??
4.What else should I check or test before I start doing spring maintainance, and fix my problem?
Thx in advance

siral3x · #2 02-08-2008, 10:26 PM

I remember 2 weeks ago we had 9F + my car doesn't have a block heather. I had to glow 3 times till it finally started! Is that unusual?? I mean it was dead cold BUT it would cranck and no start. I was worried that the starter will burn bc I had to crank it 20+ sec at a time. Any easier way to start a diesel in low temps like that??
Overall I'm satisfied with the car since it pulls strong and it doesn't have any other issues really. I love it, and I decided to keep it till the rust takes it away. I'm just worried abt the issue described above..

kerry · #3 02-08-2008, 10:28 PM

Add a lower radiator hose heater. Cheap, quick and effective in improving cold weather starts. 1 1/2" Zerostart on Ebay will run around $15 and it should take half an hour to install.

nate300d · #4 02-08-2008, 10:52 PM

I have a door for you in northwest Ohio.

siral3x · #5 02-08-2008, 11:02 PM

Quote:

Originally Posted by siral3x

I put over 12k miles now on the car since I bought it and it's due again for a valve adj. I just replaced some crappy Autolite glow plugs with NEW BOSCH and WOW ...what an improvement!
Now my main problem is this: I let the car glow for 20 sec and it fires right up with no issues at 20-35F weather. It runs nice and smooth for about 5 more sec after I start it and then it starts too MISS, shake, and idle loops erratically, eventualy stalls. It seems like the engine is not receiving enough fuel OR maibe to much??? I glow again, car starts fine..KEEP my FOOT on the throttle and keep it at around 1k rpm for 30-40 sec and then NO more shaking, looping, stalling! During the start up proces I can see on the white snow black ash like deposits comming out of my exhaust, BUT no smoke really..maybe a little bit.
1. How do I adjust my idle speed to 750rpm-800rpm??
2. I want to change my inj nozzles, what is the correct part number for my injectors and WHAT type and model the 85 DT is equipped with??
3. I have a set x5 (060) KCA30S35/4 241 135bar injectors that I want to rebuilt but I don't know if they came out of a TURBO OM617 or if they would work on my 1985 model OM617Turbo. Any imput??
4.What else should I check or test before I start doing spring maintainance, and fix my problem?
Thx in advance

ANYBODY???

Diesel911 · #6 02-09-2008, 01:16 AM

I will try to answer #2 and #3. Rebuilt injector part numbers for 85 300DT from Boach are(old number NAX-31) new number NAX-34.
The KCA30S35/4 is not the part number it is a code representing the parts that make up the injector except the spray nozzle. 135bar is the opening pressure of the injector and turbocharged 300D engines use them. What spray nozzles is in them now? The only way to check is to take them apart and look. The spray nozzle should be stamped D NO SD 240 and some will have a extra /with a 1 digit number. The Bosch part number for this nozzle is 0 434 250 110; the Mercedes part number is 001 017 29 12.
If your extra set test OK and has the correct spray nozzles in it they should work in any 82-85 300D turbocharged engine.
If the spray nozzles are no good you can use the rest of the injector and install and test with new spray nozzles. C Sean Watts is selling Monark Spray Nozzles that match your application (this is a biosed opinion as I just recieved my set of 5 spray nozzles today).

Diesel911 · #7 02-09-2008, 01:18 AM

For setting your idle speed try this site: http://www.pauldrayton.com/uploadfiles/merc/Service/W123/Main.html

toomany MBZ · #8 02-09-2008, 05:25 AM

The pic shows the idle adjustment screw, there is a lock nut on the bottom, I used a deep socket of the proper size, and a flat screw driver on the screw itself.
You may be getting an air leak in the fuel system somehow.
Good luck.

tobybul · #9 02-09-2008, 07:28 AM

If you suspect dirty nozzles, try diesel purge first. If that does not work, unless you want to do the work yourself, why not bring the nozzles to a diesel service shop.

siral3x · #10 02-09-2008, 09:06 AM

Quote:

Originally Posted by toomany MBZ

The pic shows the idle adjustment screw, there is a lock nut on the bottom, I used a deep socket of the proper size, and a flat screw driver on the screw itself.
You may be getting an air leak in the fuel system somehow.
Good luck.

If it was a air leak then it would do that all the time. It only does it on a cold start. I'm sure the compression is not perfect but still I'm worried.
btw thx for the pic!

siral3x · #11 02-09-2008, 09:12 AM

Quote:

Originally Posted by Diesel911

I will try to answer #2 and #3. Rebuilt injector part numbers for 85 300DT from Boach are(old number NAX-31) new number NAX-34.
The KCA30S35/4 is not the part number it is a code representing the parts that make up the injector except the spray nozzle. 135bar is the opening pressure of the injector and turbocharged 300D engines use them. What spray nozzles is in them now? The only way to check is to take them apart and look. The spray nozzle should be stamped D NO SD 240 and some will have a extra /with a 1 digit number. The Bosch part number for this nozzle is 0 434 250 110; the Mercedes part number is 001 017 29 12.
If your extra set test OK and has the correct spray nozzles in it they should work in any 82-85 300D turbocharged engine.
If the spray nozzles are no good you can use the rest of the injector and install and test with new spray nozzles. C Sean Watts is selling Monark Spray Nozzles that match your application (this is a biosed opinion as I just recieved my set of 5 spray nozzles today).

I'm going to visit my parents back in Europe in April ,so I'm gonna grab 2 sets of the Bosch nozzles. I like to stick with OEM, plus they only cost me 10-15euro a piece.

siral3x · #12 02-09-2008, 09:20 AM

Quote:

Originally Posted by tobybul

If you suspect dirty nozzles, try diesel purge first. If that does not work, unless you want to do the work yourself, why not bring the nozzles to a diesel service shop.

I have tried diesel purge and it did improve somewhat my idle, but it did not fix it. Yep, I'm having the injectors rebuilt back in Europe since I'm visiting soon. I'm willing to call a diesel service shop here too...any recomendation?? I drive from Ludington to Holland MI, every weekend, any shops around??

Diesel911 · #13 02-09-2008, 10:53 AM

Quote:

Originally Posted by siral3x

I'm going to visit my parents back in Europe in April ,so I'm gonna grab 2 sets of the Bosch nozzles. I like to stick with OEM, plus they only cost me 10-15euro a piece.

Hopefully the Bosch nozzles you get in Europe will be made in Europ!
Find out how much you can import back without customs duty to the US and also buy some Bosio spray nozzles for 300D turbo diesels if the price is good (they were around $37 each here in the US); as they would be an easy sale for you when you get back.
By the way several member have reported good results with the Monark (also Made in Germany) spray nozzles.

When I worked security at the Carnival Cruise line terminal here in Long Beach US citizens were allowed to bring in $500 worth of goods from Mexico duty free (not alcohol though). But you will need to check this. If you have family there you might be able to start a small import business!

blackestate · #14 02-09-2008, 12:57 PM

I would still guess an air leak, as the fuel is cold it is harder to pump, so I would look before the IP, maybe the lift pump, or hand pump?

Another thing I learned here is that unlike a lot of cars, on my 85 300sd the glow goes for 30 seconds or until the key is turned to start. Even if the light gose off. On really cold mornings I count a 15-20 slow count and it fires a lot easier, usually on the 1st try.

zeke · #15 02-09-2008, 01:12 PM

Quote:

Originally Posted by blackestate

I would still guess an air leak, as the fuel is cold it is harder to pump, so I would look before the IP, maybe the lift pump, or hand pump?

Another thing I learned here is that unlike a lot of cars, on my 85 300sd the glow goes for 30 seconds or until the key is turned to start. Even if the light gose off. On really cold mornings I count a 15-20 slow count and it fires a lot easier, usually on the 1st try.

x2 - I had rough and inconsistent idle on my 240D and on my 300TD, and in both cases, air in the system was at least partly to blame. I changed the fuel lines and tinkered until I stopped seeing air bubbling into the primary filter and until I was sure that there was no air in the secondary filter, and it made a world of difference in both cars!

I thought I needed new motor mount (still do), but getting the air out of the system and getting the idle right smoothed it out enough for me to justify putting off the motor mount for a few more months!