Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-17-2012, 12:44 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
Troubleshooting a startup issue OM617 1984 300TD

I'm having a difficult time getting the car to start. Here is what it is doing.
  • After 2-3 long GP glows I attempt a crank.
  • The engine does not fire for a long time. It just has a galloping cadence that gets quicker and quicker.
  • After about 3 20-30second cranks it fires up and belts out smoke(slightly dark at first but mostly white)
  • Once it warms up it drives fine and cranks easier if it's still warm.

I do not think it's the glow plugs. They test OK out with resistance and I'm getting voltage to the relay. The relay lasts for 30 seconds or so when I engage the pre-glow. Also, one is new from last week and another was tested recently.

After reading the forum a bit I'm leaning toward a valve adjustment. The odd thing is that it was turning over much better before I had some air in the lines on a cold day. Since the air in the lines, I've had this issue on starting. Is it normal for valves to go out of spec all of a sudden or could it be another issue? I adjusted the valves in the spring of 2011 and it was the first time I have ever done it. I'm not confident I did it perfectly then so that's why I lean toward the valves.

__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
  #2  
Old 01-17-2012, 12:49 PM
Registered User
 
Join Date: Jan 2002
Posts: 18,355
Those symptoms are identical to the ones that occur when the glow plugs are not working. I'd still suspect the glow plugs. Have you confirmed voltage to the plugs with the key in the glow position?
__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
Reply With Quote
  #3  
Old 01-17-2012, 01:06 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
I will check it again. I was getting it last week by putting one probe on the threaded tip and the other on the negative battery terminal.
__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
  #4  
Old 01-17-2012, 01:15 PM
Biodiesel300TD's Avatar
|3iodiesel300T|)
 
Join Date: Dec 2004
Location: Albany, OR
Posts: 4,845
No valves don't go out of adjustment all of a sudden. Sudden hard start issues are usually glow plugs. A valve adjustment certainly won't hurt. The valve clearances get tight over time which leads to the valves not closing all the way which causes reduced compression. Air in the lines is also compounding the issue. If you have out of adjustment valves, air in the lines and a bad glow plug or two it's going to make is hard very hard to start. Are you running any biodiesel. If you have much biodiesel and it's cold this is also going to compound the issue.

A sudden change points to GP. I always pull the GPs to test them. I've never had luck testing the resistance. I pull them and give them 12v. I can see for sure if they are actually working. They should glow BRIGHT orange to almost white if they are brand new. If they aren't at least getting bright orange I'd replace them. Careful they get up to around 1600*F.
__________________
Andrew
'04 Jetta TDI Wagon
'82 300TD ~ Winnie ~ Sold
'77 300D ~ Sold
Reply With Quote
  #5  
Old 01-17-2012, 01:24 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
I do run a SVO system(two tank). I always purge and start/stop on diesel though.

How quickly should the plugs heat up on the bench?
__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
  #6  
Old 01-18-2012, 01:22 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
I checked the voltage in the relay and it checks ok. I also checked the first two plugs again and they are getting voltage until the relay clicks off after about 30sec.

Is it possible I have an air leak? Otherwise I guess I will pull the other glow plugs and test/put new ones in.
__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
  #7  
Old 01-18-2012, 01:32 PM
Registered User
 
Join Date: Jan 2002
Posts: 18,355
The diagnosis just got more complicated because one symptom of a dying IP as a result of running SVO is hard starts. I would remove the plugs and bench test them with 12 volts. I'd also do a compression test when they are out.
__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
Reply With Quote
  #8  
Old 01-18-2012, 03:23 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
I have never checked the injectors and I've had the car for almost 2 years. It has 312k on it by the way. vstech also thinks it's not the original engine.
__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
  #9  
Old 01-18-2012, 03:25 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 33,493
In about 1-2 seconds good Glow Plug should be getting really hot at the tip of the Glow Plug first.
If the Plugs are getting hottest at the center of the Glow plug the plug is no good.
A few Members have said after they reamed the Carbon out of the Glow Plug Holes their cold starting was easier. There is DIYs on alternative methods to clean out the holes.

Besides the Air in your Fuel System when was the last time the Injectors were checked?
__________________
84 300D, 82 Volvo 244Gl Diesel
Reply With Quote
  #10  
Old 01-23-2012, 01:55 PM
Registered User
 
Join Date: Feb 2010
Location: Tega Cay, SC
Posts: 292
I found the problem. Despite testing OK, the #2 glow plug was bad. Replaced it and it fired up fairly well. I am still planning on checking #3 and #4 just in case. It idles really rough once I get it cranked until it warms up. I think I definitely need a valve adjustment.

__________________

"Gerwalt" 1984 - 300TD
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 01:31 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page