603 Glow Plug Light only on for 2 seconds - PeachParts Mercedes-Benz Forum

redassag00 · #1 08-23-2006, 04:50 PM

Hey Guys,
I noticed the glow plug light on the new car only stays on for 1 or 2 seconds, cold or hot, but I still wait about 5-10 before starting. The PO said he had 6 new GPs put in.

Is this normal for a 603?

Hit Man X · #2 08-23-2006, 05:26 PM

Nope, mine stays lit for a while...

Grab an ohm meter and see what the story is... also the 603s have a temp sensor on the head, it could be funky.

85chedeng300D · #3 08-23-2006, 05:55 PM

mine is a 617 out of an '85 300D.

glow plug light stays on for a while when doing a cold start up or when it is cold especially on the winter time, but not long enough, just like yours, 1-2 secs. if it is warm outside, if the water temp is reading above 60 deg.C, after it has been driven.

so, to make the long story short, my car's glow plug light varies with the temperature of the engine. longer if it cold and shorter if its warm.

what's important is the starter turn and the engine starts right up on a single turm of the key without hesitation.

redassag00 · #4 08-23-2006, 05:58 PM

My 83 300D Turbo glows and starts just fine with no problems.

markg612 · #5 08-23-2006, 06:15 PM

Ok, now that the irrelevant flatulence has cleared, let's solve your problem. The controller has a temperature reliant time curve that increases as detected temperature decreases. Glow time can vary from 1 to 15 seconds. There is a split in the 603 production and installation that added an afterglow feature to the glow controller. So there are some with and without afterglow. The ten cent check is remove the dust cover on the glow controller and check and see how many pins the control plug has. If I remember right 4 or 5 is the older no afterglow style, the 6 wires plug has afterglow. WHY IS THIS IMPORTANT? without afterglow the temp sensor is with in the glow controller housing on the circuit board, with afterglow, a coolant sensor supplies temp info to vary the glow time. The split came mid year of production like 8/86??? Check the 602/603 manual as it stipulates trouble shooting for both styles with prints. Also, there is a self check circuit that test the glow plugs, if the resistance isn't correct, i.e., a glow plug out OR a working but high resistance plug, this will effect operation time. The intelligence in the box is more extensive than one would think. No glow light means a dead plug, among other things. You can check all six from the heavier 6 pin connection on top of the glow controller. I can send you the pdf of the 602/603 manual, but i can't get to it until after labor day OR I know there is a link that someone here has that takes you to the manuals online.

Curious, who did the work (i.e., Benz shop or meat heads are us) and how long was it between failures?

PanzerSD · #6 08-23-2006, 07:27 PM

Quote:

Originally Posted by 85chedeng300D

so, to make the long story short, my car's glow plug light varies with the temperature of the engine. longer if it cold and shorter if its warm.

My light in my 80 SD (617) stays on for 10 seconds regardless of engine temp
and it starts fine...could my temp sensor be funky on the cold side?

would a 1980 SD have this afterglow feature?

rdanz · #7 08-23-2006, 07:58 PM

In real warm weather thats normal a second or two.

CSchmidt · #8 08-23-2006, 08:59 PM

The 603 timers seem to be optimistic. Does it seem to start ok? I think even if the light goes out it keeps glowing for about 30+ seconds or until you start. So if you turn to glow postion, wait the usual time even if the light is out, does it start fine?

You might also check the relay fuse, the flat 80amp one in the relay box. It may have a crack and separate as it heats up during a glow cycle. I had one that showed continuity cold, but then would separate during a glow cycle.

Chuck

85chedeng300D · #9 08-23-2006, 09:56 PM

Quote:

Originally Posted by Got_The_Benz

My light in my 80 SD (617) stays on for 10 seconds regardless of engine temp
and it starts fine...could my temp sensor be funky on the cold side?

would a 1980 SD have this afterglow feature?

according to your description, probably not!? mine is an '85 and yours is an '80's. as i've said, mine varies with the water temp. my car does have another coolant temp sensor that sends signal to the glow plug relay whether to extend or shorten the period of time to energize the glow plug. more time if cold and short time if warm or hot.

redassag00 · #10 08-23-2006, 11:42 PM

Quote:

Originally Posted by markg612

Ok, now that the irrelevant flatulence has cleared, let's solve your problem. The controller has a temperature reliant time curve that increases as detected temperature decreases. Glow time can vary from 1 to 15 seconds. There is a split in the 603 production and installation that added an afterglow feature to the glow controller. So there are some with and without afterglow. The ten cent check is remove the dust cover on the glow controller and check and see how many pins the control plug has. If I remember right 4 or 5 is the older no afterglow style, the 6 wires plug has afterglow. WHY IS THIS IMPORTANT? without afterglow the temp sensor is with in the glow controller housing on the circuit board, with afterglow, a coolant sensor supplies temp info to vary the glow time. The split came mid year of production like 8/86??? Check the 602/603 manual as it stipulates trouble shooting for both styles with prints. Also, there is a self check circuit that test the glow plugs, if the resistance isn't correct, i.e., a glow plug out OR a working but high resistance plug, this will effect operation time. The intelligence in the box is more extensive than one would think. No glow light means a dead plug, among other things. You can check all six from the heavier 6 pin connection on top of the glow controller. I can send you the pdf of the 602/603 manual, but i can't get to it until after labor day OR I know there is a link that someone here has that takes you to the manuals online.

Curious, who did the work (i.e., Benz shop or meat heads are us) and how long was it between failures?

\\Very good info. I'll be looking tomorrow. THe plugs were replaced in Feb of this year by Ed Hicks Imports (a Mercedes Dealer).

I may also add that right now, its 100+ every day here, so it may not need to glow that long.

redassag00 · #11 08-24-2006, 09:20 AM

Update, I just checked, my car has a production date of 04/87!

#12 08-24-2006, 09:25 AM

I had a GP relay problem. Bought a used one, and this used one only glows the light 1-2 seconds irrespective of temperature. I checked the current, and the relay glows the actual plugs well longer than that, fading out after 10 seconds or so (you can actually hear the clunk of the relay switching). So I use the light as reference for my plugs (all newish), and the klunk for references in the winter. Otherwise, I just wait a few seconds in the summer. Starts up fine. You're smarter than the smartest little light. That's what I keep telling myself.

markg612 · #13 08-24-2006, 01:10 PM

Most likely at 4/87, you have afterglow. (my 190D is a 3/87 with afterglow) That being the case, there would be a temp sensor, and as I mentioned, when I get home, I'll look on the prints and or send the PDF to you. There are 3 or 4 sensors, one dual one that the aux fans uses one side of that trips at 105°C, the 40°C for the climate control, the temp gauge sender and, one or two more if i remember, but without the prints, I don't want to guess.

Hey Chuck--the no afterglow 603 GC opens when you crank whether it was done glowing or not, the afterglow GC continues as you mentioned. I don't think the 617 GC, but don't quote me, ever had the afterglow feature as I was told by MB that it was developed late in 86 for the 4 and 5 cylinder 60x engines due to poor cold start qualities brought on by the "revolutionary" aluminum head and pre-chamger design that resulted in greater heat dissipation. While the glow plugs were plenty hot to start, the head wouldn't heat up fast enough to continue combustion and the engine would subsequently stall without additional glowing from restart or a quick wrist to double glow after start. The 603 was less susceptible due to more cylinders, more mass, more momentum. The 602/601s really struggle in sub 0°C start and warmup without afterglow. The 601 was only in the US from 84-85 201s replaced by the 602 in the 86-87 201s and 90-93 124s, but continued in production in Europe until replacement by the 604/5/6 DOHC evolution in 94. Same family, just a new DOHC head.

Interesting failure of the strap fuse!

a2t · #14 08-24-2006, 01:12 PM

87 300D turbo.

Whats it mean when I get no glow plug light at all? I pulled the cluster and the bulb is OK but no light. It used to light for a couple seconds, but that stopped.

About half of the interior lights do this, too. But they did this before the glow plug light quit working. The bulb is fine but no light (1 that comes to mind is the gear selector illuminator). Much of center console lights are same way. Tach bulb is fine but not coming on either.

Anyways, if I dont wait 5 sec or so, it cranks real long. But if I wait then it fires right up.

Think its 1 or more bad glow plugs?

markg612 · #15 08-24-2006, 01:21 PM

AT2--sounds like a power/ground issue with the instrument lights, most likely a bad plug regarding the glow light, BUT, could be a common ground shared by the other instrument lights. You could use some prints!