weird starting problems glowplugs/injector 1983 300sd - PeachParts Mercedes-Benz Forum

1977busman · #1 10-01-2010, 03:40 PM

So recently it has been getting much cooler here at night. And if it id below 55 my car does not like to start very easily. It will fire up just like always then shutter back down to a halt. If I tap the accelerator while its just fireing, it stays and eventually evens out.
Background info:

bought car in august and never had any problems
Car now has 212,500 miles on it
my number 5 injector is "damp" but not dripping or anything
Car will start fine once initially started for the day.
I can start in with or without the glow plugs, it just turns over a few more times without
I know I am getting at least a few glow plugs working, because it starts noticeably different with or without them.
If I plug the car in it does start a little better, but still shutters a little.

I did attempt to test glow plugs, and here is what I did:

got into the relay and tested ohms on each hole on the connectors going to glow plugs-I got .9 ohms for each one.
Then I checked the strip fuse and it was fine.
Tested battery and im getting 12.98v when NOT running.
Then tested each glow plug, and this is where I think I messed up. I held the negative to the nut of the plug, and the positive to the end, and got .9ohms on each one. Was I supposed to remove the wire to the glow plug? and was I supposed to remove the whole glow plug itself?

So should I be looking for glow plug problems, or fuel problems? and Please tell me if my procedure was correct with the testing.

Oh and ill be back later with transmission problems...

barry123400 · #2 10-01-2010, 05:22 PM

Well I would get someone to monitor the dash light while reading the voltage present at the glow plugs. This is with a cold engine.

There should be twelve volts on those plugs for awhile. Actually an alternative quick check does the interior light dim during the glow plug cycle? For how long with the engine cold?

You are right in that the glow plug circuit being in good health is the first item.

1977busman · #3 10-01-2010, 05:48 PM

i will check in the morning when shes good and cold, as ive been driving it all evening and will continue to be driving.

cirrusman · #4 10-01-2010, 06:08 PM

Here's how you can check the plugs: http://dieselgiant.com/glowplugrepair.htm
Also, in the owners manual they do warn you that the car will get a bit harder to start in cold weather and here's the procedure from that manual:
"Depress accelerator to the floor. Turn key in steering lock counterclockwise to the stop. Release key only when the engine is firing regularly and back off accelerator slowly. Do not interrupt the starting process. If the engine is very cold it is possible that it will fail to start on subsequent attempts. In ambient temperatures of less than -18°C / 0°F, depress accelerator three times prior to starting."

whunter · #5 10-02-2010, 11:51 AM

Quote:

Originally Posted by 1977busman

So recently it has been getting much cooler here at night. And if it id below 55 my car does not like to start very easily. It will fire up just like always then shutter back down to a halt. If I tap the accelerator while its just fireing, it stays and eventually evens out.
Background info:

bought car in august and never had any problems
Car now has 212,500 miles on it
my number 5 injector is "damp" but not dripping or anything
Car will start fine once initially started for the day.
I can start in with or without the glow plugs, it just turns over a few more times without
I know I am getting at least a few glow plugs working, because it starts noticeably different with or without them.
If I plug the car in it does start a little better, but still shutters a little.

I did attempt to test glow plugs, and here is what I did:

got into the relay and tested ohms on each hole on the connectors going to glow plugs-I got .9 ohms for each one.
Then I checked the strip fuse and it was fine.
Tested battery and im getting 12.98v when NOT running.
Then tested each glow plug, and this is where I think I messed up. I held the negative to the nut of the plug, and the positive to the end, and got .9ohms on each one. Was I supposed to remove the wire to the glow plug? and was I supposed to remove the whole glow plug itself?

So should I be looking for glow plug problems, or fuel problems? and Please tell me if my procedure was correct with the testing.

Oh and ill be back later with transmission problems...

* Replace the leaking injector return hose.
* Glow plugs link thread All diesel models
http://www.peachparts.com/shopforum/showthread.php?p=1019018

.

mach0415 · #6 10-03-2010, 05:51 AM

Quote:

Originally Posted by cirrusman

Here's how you can check the plugs: http://dieselgiant.com/glowplugrepair.htm
Also, in the owners manual they do warn you that the car will get a bit harder to start in cold weather and here's the procedure from that manual:
"Depress accelerator to the floor. Turn key in steering lock counterclockwise to the stop. Release key only when the engine is firing regularly and back off accelerator slowly. Do not interrupt the starting process. If the engine is very cold it is possible that it will fail to start on subsequent attempts. In ambient temperatures of less than -18°C / 0°F, depress accelerator three times prior to starting."

This sounds like an old carb-type gasser.

tangofox007 · #7 10-03-2010, 09:58 AM

Quote:

Originally Posted by 1977busman

So should I be looking for glow plug problems, or fuel problems?

Sounds like a fuel problem to me.

Quote:

Originally Posted by 1977busman

It will fire up just like always then shutter back down to a halt. If I tap the accelerator while its just fireing, it stays and eventually evens out.

You might need to adjust your accelerator linkages. Could be too much tension on the shut-down lever at the IP.

1977busman · #8 10-03-2010, 10:19 AM

well I didnt get a chance to use the multimeter to test the voltage at the glowplugs, but the interior lights definetely dim down. As far as needing to press the accelerator because it is getting colder, I do not think that is the solution. Its only been 45-50degrees, its not like im trying to start in teen or anything. My return line hose is comming today or tommorow for the 1992, so ill just get some extra. Thanks for all of the responses.