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 10-19-2004, 04:26 PM
*
 
Join Date: Nov 2003
Location: Tiki Island Texas
Posts: 1,049
How does the older GP relay work

Switched to the fast GP’s last Saturday. Much better starts, but I also put in new (rebuilt injectors) so that may be some of it. I didn’t install the new relay that came with the kit after reading all the posts here, and not really having a clue about how to wire it in. The price of the kit was less than a relay so I can’t think it’s very good anyway. I didn’t throw any old parts away. So how does the old original relay work? Does it sense the temp of the plugs, or is it a timer? Plugs now glow quicker but it’s still about 15 seconds, and I wait until the lights off to start the car. Must be a temp sensor as they’ve always glowed for just a spilt second after the cars run.
By not putting in the new relay, am I throwing a strain on the electrics in any way?

__________________
89 300E
79 240D
72 Westy
63 Bug sunroof
85 Jeep CJ7
86 Chevy 6.2l diesel PU

"The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane."
Marcus Aurelius
Reply With Quote
  #2  
Old 10-19-2004, 04:51 PM
Registered User
 
Join Date: Jan 2003
Location: Reno/Sparks, NV
Posts: 3,063
I recommend that you install the new relay, otherwise you're just wasting your money on the kit. The relay in this kit is the same as the one you can buy by itself and the main feature of it is the afterglow (glow plugs keep glowing briefly after starting the engine). There is a temperature sensor that's bolted into the engine, but regardless of the sensor the relay will cut out after a brief time (about 30 seconds). You can hear this as a click.
__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL
Reply With Quote
  #3  
Old 10-19-2004, 05:40 PM
Waitn For The Bus All Day
 
Join Date: Jul 2004
Location: south east pa.
Posts: 1,786
Every diesel I've had before I got my benz, the GP would "cycle" on/off a couple times when engine first started. My benz GP light comes on when the key is first turned, I wait for light to go out then immediately start. After it starts, the glow plugs don't cycle at all .


Is this normal?

Cheers,

Bill
Reply With Quote
  #4  
Old 10-19-2004, 05:53 PM
Registered User
 
Join Date: Jan 2003
Location: Reno/Sparks, NV
Posts: 3,063
Yes that's normal. But the plugs don't stop glowing as soon as the light goes out, though they do stop if you start the engine unless you have one of these new relays. The light just indicates the recommended wait time before starting. With older relays, this recommended time is often too short so just let it glow longer before starting the engine.
__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Last edited by DieselAddict; 10-19-2004 at 05:59 PM.
Reply With Quote
  #5  
Old 10-19-2004, 06:40 PM
jbaj007's Avatar
Registered User
 
Join Date: Jun 2001
Location: Santa Monica, CA
Posts: 2,053
crash9,

I'm surprised you even need glowplugs where you live!
__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)
Reply With Quote
  #6  
Old 10-20-2004, 10:11 AM
Waitn For The Bus All Day
 
Join Date: Jul 2004
Location: south east pa.
Posts: 1,786
Quote:
Originally Posted by DieselAddict
Yes that's normal. But the plugs don't stop glowing as soon as the light goes out, though they do stop if you start the engine unless you have one of these new relays. The light just indicates the recommended wait time before starting. With older relays, this recommended time is often too short so just let it glow longer before starting the engine.
I thought my GP's needed replacing because I have to start twice at times. Before i replace them I will surely try letting them glow longer.

Once again, THANKS!!

Cheers,

Bill
Reply With Quote
  #7  
Old 10-20-2004, 12:17 PM
*
 
Join Date: Nov 2003
Location: Tiki Island Texas
Posts: 1,049
Quote:
Originally Posted by jbaj007
crash9,

I'm surprised you even need glowplugs where you live!
I’m up higher at about 5,000’ – 95 deg summers and snow and mid teens in the winter, but yeh. I should try with the new injectors just to see, but the cars at around 390lbs. comp., and they put the plugs in for good reason.
Now I’m getting confused about the relay. The glow light does not stay on as long as it did with the old GP’s, so I’m assuming it is not a timer, but a heat sensor. Then again maybe I’m imagining things. I understand the afterglow thing, but also have read mixed ideas about whether that’s such a good thing.
My concern is removing the ground strap on the new plugs – were the resistors on the old plugs insulated from the block? I’ve been around to many English cars to want to mess with the electrics too much. I guess the fuse strip would have blown if this weren’t proper – I’m also just a little paranoid by nature. I drive in the middle of no place most of the time.
__________________
89 300E
79 240D
72 Westy
63 Bug sunroof
85 Jeep CJ7
86 Chevy 6.2l diesel PU

"The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane."
Marcus Aurelius
Reply With Quote
  #8  
Old 10-20-2004, 03:15 PM
Waitn For The Bus All Day
 
Join Date: Jul 2004
Location: south east pa.
Posts: 1,786
Quote:
Originally Posted by crash9
I I’ve been around to many English cars to want to mess with the electrics too much. I guess the fuse strip would have blown if this weren’t proper – I’m also just a little paranoid by nature. I drive in the middle of no place most of the time.
So you know the saying about MG's--don't go out after dark

Never understood how positive can be ground....

Cheers,

Bill
Reply With Quote
  #9  
Old 10-20-2004, 03:17 PM
boneheaddoctor's Avatar
Senior Benz fanatic
 
Join Date: May 2004
Location: Hells half acre (Great Falls, Virginia)
Posts: 16,007
Quote:
Originally Posted by bill murrow
So you know the saying about MG's--don't go out after dark

Never understood how positive can be ground....

Cheers,

Bill

They don't call Lucas "The Prince of Darkness" for no reason at all...................

Ever hear the comment about British electrical systems being inferior to and at best equal to an elaborate system of Tallow candles?
__________________
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

Last edited by boneheaddoctor; 10-20-2004 at 03:29 PM.
Reply With Quote
  #10  
Old 10-20-2004, 03:24 PM
Waitn For The Bus All Day
 
Join Date: Jul 2004
Location: south east pa.
Posts: 1,786
Quote:
Originally Posted by boneheaddoctor
They don't call Lucas "The Prince of Darkness" for no reason at all...................
I've had several Triumph/BSA motorcycles converted to "normal" wiring just so I would have lights to see the deer in the road. Flashlights don't work well, even in a pinch

Not much wiring on a bike compared to cars so I guess bikes are fairly easy to convert because my buddys friend didn't charge much to do the conversion


Cheers,

Bill

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 01:18 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page