Have you looked into the glow contacts in the gorilla knob as mentioned in the thread I linked?

__________________
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

I purchased a '74 240D with non functioning gorilla knob system. (The PO had taken a hammer to the dash in anger when the steering lock locked while driving- I know - it did not fix the problem. But it allowed me to get a car with excellent tires, a great motor and manual trans for $200.)

The car was trailered home. In an effort to see if the motor even ran, I used one large battery and 3 jumpers. I disconnected the gorilla knob feed to the glow plugs, grounded the battery to the car, then jumped 12v to the high side of the glow plugs. I counted to 10, disconnected the feed to the glow plugs, then jumped 12v to the starter. With a spark and a click, it was running perfectly. The dash salt shaker glow plug is in series, I think, with the motor's 4, so don't connect for long, or perhaps one of the engine plugs will melt.

If your car starts easily with this, I suggest you check the dash salt shaker. You can get to it easily by pulling out the instruments. Make sure it get's 12v on the high side, that it is not open, and that you have 12v at the gorilla knob switch (high side). One of those parts is probably bad, the dash glow plug or the switch. I'd buy used for replacement, those parts are usually reliable.

'Hope this helps, Ron

__________________
1971 220D, daily driver, new paint, 142K
1973 220D, low compression
1975 300D, back on the road! 166K
1971 220D, salvage, rear hit, engine excellent
1972 250, bad cam, but runs!
1971 230, engine stuck
1971 220D, low compression, rusty
1976 240D, salvage, engine excellent
1966 230SL, water in oil after rebuild

Be extreeeemely careful about using 12-v on the loop plugs. They are designed to only take a fraction of that. In normal series operation, each plug including the one in the "shaker" window shares a part of the voltage drop as well as do the squiggly metal jumpers. So actual drop across one should be no more than 1.8 to 2 volts!!!!

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

Happy glow plug difficulty season everyone!

Party on!

__________________
1979 240D, 4spd manual, Power Sunroof, manual windows, 147k miles, Pastel gray/Black MB Tex.
1991 300D 2.5 - Smokes like it's on Crack!

According to my service CD, the glow indicator in the dash is taken out of the circuit when you pull the starter knob to the "start" position, to reduce the voltage drop...but the plugs still have power during cranking. So, if there is a problem with the switch contacts or an broken glow indicator, the engine will still start after a few seconds of cranking as the glow plugs come up to temperature (as it would if you forgot to wait).

While I've never checked this myself, I would imagine you could use an ohmmeter and check resistance on each terminal of the dash indicator, and also between each glow plug - i.e. one lead on the bus bar on each side of each individual plug, starting with the one closest to the firewall (with power off, of course). I would think that if one was burned out, you could tell by the resistance indicated (or lack thereof).

I made a wire jumper to bypass a bad glow plug in case of an emergency on the road...of course, not intended to use long-term as it would allow more current to the remaining 3 plugs.

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1976 240D "Katja"

Which now explains to me why the motor starts so easily, even with the glow plugs not functioning when pulling on the glow plug switch.

I didn't realize the gorilla switch would also engage the glow plugs. This is not outlined in the Chilton schematic. I never should have banked entirely on one of those manuals to be completely correct. Never have been in the past, why should now be any different.

Tomorrow I will pull the instrument cluster and check it out at the salt shaker and at the gorilla switch. I will also be checking at the #4 glow plug while some tries starting the motor to see if there is voltage then.

To me there is no sense in checking out any of the glow plugs until I get and or confirm any power out to #4 first. Which has yet to occur.

Thank you Katja for your additional insight!

I believe one of my next steps will be to get an OE cd for this vehicle so I can stop wasting time with nonsense.

Any recommendations? I have briefly looked at the mercedes web site to find that there are several choices ranging from about $20.00 to about $60.

Kerry,

No, I have not had the time yet. The skeeters are winning around here at the moment. I tried to get into it last night, but had troubles staying on the ground. One would think I was in Wisconsin again. As I recall that is the state bird there.

I will have some time tomorrow to look deeper into it. Instrument cluster will be coming out and I will be replacing bulbs there, checking the dimmer rheostat, the shaker & the gorilla switch all at once.

Thanks to all of you for your assistance and insight. I am sure I will get the answers that I need tomorrow with all the information you folks have armed me with.

I will keep you posted.

Thanks again,
Rick

Thanks Ron,

Such great information from an awesome group of people!

I have a feeling this problem will be solved in no time.

Thanks again,
Rick

OK, here's the latest. The glow plugs are working. The gorilla switch is working. Yay. I am a bit confused though. I have been told by the dealer that the switch on the console is for the glow plugs, too. It does not light them up. No problem. I will just fire up off of the gorilla switch for now until I get the MB CD service repair manual to further study.

Thanks for all of your help!

Rick

Really?! My 240D is as loud as a Mack truck

The dash indicator is the first thing in the glow plug series, if its got a bad connection, that'll stop the flow of current. Try checking for 12v on the leads of the indicator. You can unscrew the salt shaker cap and then use a small screw driver to loosen the collars for the two legs of the indicator, then the indicator pulls straight out. I'll post the wiring schematic from the CD.

The $20 cd shop manual is great. PM me your email address and I'll send you the part pertaining to the glow plugs to give you a taste of the manual.

Also, am I understanding you correctly that there are TWO knobs involved with starting your car? Mine has the one gorilla knob on the dash to the left of the steering wheel. Did you say you have another on the center console? The manual only mentions the one on the dash, even for 615 engines.

Well, good luck, and if you want that section of the manual, send me your email.

Attached Thumbnails

 

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

PM sent. My cd is on it's way, but it will be nice to take a look at a good schematic in the mean time. Thank you pizzachef. The diagram in your post is pretty much the same as the Chilton one, but much more legible and detailed.

The knob on the center console is a push / pull with a light in the middle. Oh crap, it just dawned on me that it is probably the rear window defogger / defroster. It just won't stay on. Duh. To much schematic reading too many days in a row. What a brain fart!

Oh well, just another day in paradise.

Thanks everyone for all of your help and patience with a MB Diesel Noob! Hopefully, my mistakes will one day help someone else out on this message board.

Have an awesome night!

Rick

What happened to cause the glowplugs to start working?

__________________
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

Well Kerry,

I am almost embarrassed to say that they worked all along and I didn't realize it. I was mis-informed and was attempting to use the wrong switch to light off the glow plugs. I had a feeling that this diesel was starting up way too easily for 50 degree temperatures. The glow plugs were working, just not getting enough warm up time. If you look at my previous post in this thread, you will see the aha moment when I finally figure out what that other switch is actually for. Duh! I did not know that the glow plug portion was actually built into the gorilla switch even after spending days looking at the wiring diagrams. Well, yes I did, but it hadn't sunk all the way into this thick skull yet.

It was due to the information from all of you folks here and looking at a few youtube videos on cold starts along with a good nights sleep that got me the answers that my tired out brain needed.

My brain seems to keep working on things while I sleep and the answers come to me in the next day or so, normally. It was just too overloaded to get the answers the first day or two. Seventy to eighty hour work weeks for this old fart are getting to be too much these days.

I had my son operate the gorilla switch slowly tonight while I had a voltmeter on #4 glow plug. I think my face lit up brighter than the meter and the salt shaker did when it kicked on.

The only thing I can say is I'm glad I didn't get frustrated enough to take a hammer to it like a previous post mentioned. These MB parts are way too expensive for me to be doing things like that!

I don't understand what you were doing wrong. So you turned the glowplugs on and didn't know it?

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

I was using the gorilla switch to start, which actually defaults glow plugs on while starting. I just wasn't allowing any warm up time. Hence, the motor starts easier with some glow, even if minor.

I was pulling on other switch for glow, which didn't do anything other than lighting the bulb in the knob. I really feel dumb in retrospect / hindsight.