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 03-06-2004, 10:39 PM
Zeitgeist's Avatar
Banned
 
Join Date: Aug 2003
Location: Cascadia
Posts: 2,304
Afterglow and the Violet Wire

I posted this on the mbz.org diesel list earlier today:

As many of you are probably aware, if you snip the violet wire at the GP relay, you can get your GP's to glow for an extended period after the engine is running. This should theoretically reduce smoke, emissions, and coking issues. The problem is that snipping the wire also forces the GP's to run 'afterglow' even when the engine is warm, which will diminish the life expectancy of the plugs. Many folks have wired in a manual switch to turn off this feature, but I wanted a more 'hands-free' operation.

I installed a thermally switched relay into the GP relay's violet wire circuit. I used an NC (normally closed) relay from a Volvo 700 series fusebox. These are a 5 terminal relay, similar in look to the familiar 4 terminal NO (normally open) versions used in Euro headlite conversions and countless other little projects. These NC relays have an additional 87a terminal to which one side of the violet wire is connected, opposite the 30 common for the other side. http://www.the12volt.com/relays/relays.asp Be careful of other similar 5 terminal relays with an 87b terminal--these are just NO relays with two bridged terminals--these won't work.

I piggy-backed onto the 50 C thermal switch above the thermostat housing on my '87 300 td OM 603, which is apparently designated to assist and smooth cold shifting in the transmission.

When the relay is energized, the violet wire is snipped--afterglow enabled. In this phase, the 50 C thermo-switch has continuity with ground.

When the relay is not energized, the violet wire is bridged--afterglow is disabled. In this phase the thermo-switch has no continuity with ground.

I'll let you know how well this works in real world situations.

Reply With Quote
  #2  
Old 03-07-2004, 12:24 AM
190D22's Avatar
Driver's Side lights
 
Join Date: Apr 2002
Location: Columbus, Ohio
Posts: 876
That's ingenious! I will investigate this further and will wire up a switch to mine. That is if my relay HAS a purple wire.
__________________
1984 190D 2.2 Auto 220k
2001 Jeep Cherokee Sport 70K
2004 Lexus RX-330 ??K
2005 Chrylser Crossfire LTD 6K

Play guitar? Go to www.cyberfret.com for free online lessons!
Reply With Quote
  #3  
Old 03-07-2004, 12:33 AM
Zeitgeist's Avatar
Banned
 
Join Date: Aug 2003
Location: Cascadia
Posts: 2,304
I believe all MB GP relays for the OM 616/617 and OM 601/602/603 series engines have a purple wire. All of the later OM 606 engines, and possibly some '90's era OM 603's had an afterglow relay installed at the factory. Try the switch first, then if you like the results, go for the relay option.

Good luck.
Reply With Quote
  #4  
Old 03-07-2004, 01:09 AM
190D22's Avatar
Driver's Side lights
 
Join Date: Apr 2002
Location: Columbus, Ohio
Posts: 876
I'll just stick with the switch. That way I can keep her glowin when I want. I have no problem with a switch.
__________________
1984 190D 2.2 Auto 220k
2001 Jeep Cherokee Sport 70K
2004 Lexus RX-330 ??K
2005 Chrylser Crossfire LTD 6K

Play guitar? Go to www.cyberfret.com for free online lessons!
Reply With Quote
  #5  
Old 06-17-2004, 12:07 PM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,033
This is a great way to add "afterglow" cheaply, although plug life will be less than normal (duh). At next plug replacement time you could get the special afterglow-rated plugs which would help. A full factory conversion (for the 603) is expensive- you need the late relay, plugs, temp switch for the cylinder head, and some custom wiring... $200+ last time I checked. The relay+50C switch trick costs about ten bucks, tops, for a new relay. I've been meaning to do this on my car and haven't gotten around to it yet. Hmmm... maybe this weekend....

__________________
Dave M.
Boise, ID

1997 E420 - 155kmi (Bugeyes)
1994 E420 - 145kmi (Blondie)
1993 500E - 193kmi (Lollipop)
1992 400E - 189kmi (Stinky Dirty)
Check out my website photos, documents, and movies!
Reply With Quote
  #6  
Old 11-08-2004, 09:21 PM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,033
Bump! I finally did the install last month, after discovering two dead plugs (only 20kmi old - don't buy Monark brand, stick with Bosch or Beru.) Anyway the mod works GREAT. It's 100x better than simply yanking the purple wire, as it only afterglows when cold. Wish I had done this a long time ago...

Reply With Quote
  #7  
Old 11-08-2004, 09:44 PM
boneheaddoctor's Avatar
Senior Benz fanatic
 
Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Cool, need to look at my car and see about it. Would help cold weather starts a lot.
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
Reply With Quote
  #8  
Old 11-09-2004, 02:59 AM
Zeitgeist's Avatar
Banned
 
Join Date: Aug 2003
Location: Cascadia
Posts: 2,304
I suggest more folks give this mod a try, as it really does smooth out those cool early morning startups.
Reply With Quote
  #9  
Old 11-09-2004, 09:20 AM
Registered Diesel Burner
 
Join Date: Aug 2001
Location: Northern Virginia
Posts: 2,911
Thanks - my 603 engine is particularly cold natured. Starts up instantly and runs smoothly, then within about three seconds when the glow plugs cool down it smokes and rough idles. Less of an effect when I am patient enough to run an extended glow cycle. But what it really needs is the afterglow system that MB went with in the 1990s.

I want more direct control so I'll probably go with a toggle switch and indicator light. This is a low current-carrying wire, right?

Ken300D
__________________
--------------------------
1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles
Reply With Quote
  #10  
Old 11-09-2004, 10:28 AM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,033
Quote:
Originally Posted by Ken300D
I want more direct control so I'll probably go with a toggle switch and indicator light. This is a low current-carrying wire, right?
Correct. You can make it look factory by using a rocker switch in the center console or above the ACC unit, if you can give up one of the stock switches... the fader is often bypassed when installing aftermarket stereos, that's the first candidate, second would probably be the antenna level switch (can be hardwired for 'full up' whenever the radio is on). Or you can get new (or used) wood with extra holes, but that's pricey (and hard to find used). If you add an aftermarket switch setup, try mounting them next to the headlight switch - they'll blend in pretty well over there.

Reply With Quote
  #11  
Old 11-09-2004, 10:53 AM
Registered User
 
Join Date: Dec 2002
Location: RI shore
Posts: 2,937
Nice idea. Bosch has incorporated this feature in the new glow plug relays. I think this is the kit that Phil is selling this month for 10% off. About $100 with 4 or 5 new glowplugs.
__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.
Reply With Quote
  #12  
Old 11-09-2004, 10:54 AM
boneheaddoctor's Avatar
Senior Benz fanatic
 
Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Quote:
Originally Posted by Pete Burton
Nice idea. Bosch has incorporated this feature in the new glow plug relays. I think this is the kit that Phil is selling this month for 10% off. About $100 with 4 or 5 new glowplugs.
Yes, but if you have a 116 you are out of luck........the relay is different on those........
__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche
Reply With Quote
  #13  
Old 11-09-2004, 11:09 AM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,033
Quote:
Originally Posted by Pete Burton
Nice idea. Bosch has incorporated this feature in the new glow plug relays. I think this is the kit that Phil is selling this month for 10% off. About $100 with 4 or 5 new glowplugs.
That's for the OM617 engines only. There is no retrofit kit for any OM603's. You have to either do this mod, or build your own kit using factory afterglow parts from 1990-95 model OM603's. That's the preferable method but the cost is ~$250 for the relay, coolant temp sensor, and six afterglow-rated plugs. The 'poor mans' 603 mod with the 50C switch and relay gives almost the same effect for under ten bucks. Hard to beat that...!

Reply With Quote
  #14  
Old 11-09-2004, 11:46 AM
Zeitgeist's Avatar
Banned
 
Join Date: Aug 2003
Location: Cascadia
Posts: 2,304
Potomac had a bunch of used OM603.97 GP relays on ebay last week. Was tempted to go for it as they were going cheap...
Reply With Quote
  #15  
Old 11-09-2004, 01:56 PM
michael cole's Avatar
Registered User
 
Join Date: Apr 2002
Location: waterloo ontario
Posts: 730
Wink

another variation of this idea.using a 555 timer ic and solid state relay to give you a fixed duration after glow.this could be packaged in a 35mm film canister.advantage here would be longer life on your glow plugs.details to be worked out

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 10:04 PM.


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