Hello Everyone,
I have a 1983 300sd which has had some issues lately but I have done my best to get her ready for school in a few days. The current issue is a rough starting. Right now I am looking at temperatures from low 70s to the mid 80s. In the morning I start the car and it seems to sputter and choke for some reason. Usually reving the engine up to 3000 and letting it idle settles the problem and I am off to work. Or when I am in a hurry, I just put it into reverse or drive and drive on my way. It isnt a big problem right now but lately the car starts pretty rough and I am getting worried. I dont have to crank more than usual and the glow plug light isnt long so I am consulting you folks. I have done some searching but cannot figure or find a similar issue.
What I have done lately:
Turned up the alda
changed the oil (I went to synthetic but the car has done the same thing with and without synthetic)
New glow plugs went in during march

So, what I think I either have is a bad injector but the car runs fine when it is warm, or I have a bad glow plug relay that isnt keeping enough heat in the cylinders to start. Could it also be bad compression? I dont want to start ripping the car apart as I have to leave on tuesday but I would appreciate any help anyone has. Thanks.

Douglas Kabat

__________________
1983 300sd 253,000 + 13,000 (10,000+ on veggie and biodiesel)= 266,000
1983 300sd 390,000 (Leaky windshield seal) Known to me as the shower car. Parts car now!
1 junk 300sd Watch out for the skunk that lives underneith it!

Start with the basics:

Glow Plugs. Check the resistance of each glow plug with a VOM. Pull the plug out of the relay to do the check. Any open readings signify a bad glow plug........doesn't matter if they were changed in March.

Check for voltage at one of the glow plugs when the key is turned to the #2 position. Should have 12V. If not, then the relay is suspect or the fuse under the cover is suspect.

So my first step should be to get a meter and try to see it the charging system is working correctly? I will try to do so tomorrow morning. Thanks.

Douglas Kabat

__________________
1983 300sd 253,000 + 13,000 (10,000+ on veggie and biodiesel)= 266,000
1983 300sd 390,000 (Leaky windshield seal) Known to me as the shower car. Parts car now!
1 junk 300sd Watch out for the skunk that lives underneith it!

Okay,
So here I am:
I tested the glow plugs like mentioned above by brian. I came out with all the glow plugs giving me readings around the .8 to 1.1 which according to diesel giant is okay. I also checked the fuse on the regulator and the power supply on the regulator while I had the cap off and they all checked out fine. So, I think that the charging system is fine. Where should I go from here?

Thanks again for all the help

Douglas Kabat

__________________
1983 300sd 253,000 + 13,000 (10,000+ on veggie and biodiesel)= 266,000
1983 300sd 390,000 (Leaky windshield seal) Known to me as the shower car. Parts car now!
1 junk 300sd Watch out for the skunk that lives underneith it!

Do you have voltage at one of the glow plugs when the key is first put into the #2 position?

I believe that the #2 position is when the glow plug light goes on? I checked the readings and there is 10.6 volts at the glow plugs when the light goes on. By the time the glow plug light goes out, the reading is almost 11 volts. As the light is off, I am getting a little increase in voltage but only up to about 11.2-11.3.

So, I think that the glowplugs are getting electricity fine because I think that the less voltage accounts for the voltage drop in the wires and circuit.

After the engine has started, there isn't any voltage going to the glow plugs. Is there suppose to be heat from the glow plugs after the engine has started?

Thanks

Douglas Kabat

__________________
1983 300sd 253,000 + 13,000 (10,000+ on veggie and biodiesel)= 266,000
1983 300sd 390,000 (Leaky windshield seal) Known to me as the shower car. Parts car now!
1 junk 300sd Watch out for the skunk that lives underneith it!

Do you have any maintenance history on this vehicle?

When was the last time:

1) The valves were adjusted?
2) The IP timing was adjusted?

I just adjusted the valves but have no idea about the injection pump. When I adjusted the valves, only a few were off. None of the valves were off by a lot.

Douglas Kabat

PS: I believe that I had the same issue before I adjusted the valves.

__________________
1983 300sd 253,000 + 13,000 (10,000+ on veggie and biodiesel)= 266,000
1983 300sd 390,000 (Leaky windshield seal) Known to me as the shower car. Parts car now!
1 junk 300sd Watch out for the skunk that lives underneith it!

This only happens when it is cold, right?

Try waiting for 30 seconds after turning the key to #2. The glow light will go off early, but the plugs are still heating up. Give it a bit more time before cranking it and see what happens. If we had voltmeters on these cars we would see a jump when the GP relay shuts off. I can tell by my RADAR detector. It say " Low Voltage" until the relay clicks off.

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad

If you have the interior light on you can see the brightness change when the GPs shut off.

BTW, 11V is just about correct for the GPs.

Smart idea. On the SD the overhead light goes out before the cycle is over, but if you keep the door open ...

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad

Yup, after you do it a couple of times you will have a pretty good idea how long to wait, I think the 240/300D GPs run for about 40 seconds.

I had the same problem with my 83, increased the glow time and she purrs like a kitten.

__________________
Jim Messina

1983 300 SD
2006 Silverado Z71

My glow light doesn't come on half the time which I think is due to a sketchy GP or two, however extra glow time makes up the difference. If you leave your door open you can hear the relay clunk when it turns on or off. It's pretty loud.

__________________
1983 300SD
Rusty, Loud and Proud

How do you increase the glow time?

I have a 82 300SD with a complete service history - the GP relay should be original. From I have read - there is a new updated relay that has a longer 'on time'. I don't want to buy a new relay.

BTW - My starts are rougher lately (new GP, but I will ream next time)

Thanks

Geoff