Maybe it was written by someone who is not very well versed in the engineering of the vehicle?

Maybe, just maybe, we know a bit more about the vehicle than the person who wrote that manual..........

Why does the manual state to wait until the glow plug light goes out and then start the engine? Don't we already know that this statement is false at any temperature less than 32°F.?

While you might be a champion of the written word in the FSM, don't take every last word as gospel.

This is in a post about a 617 engine.. and my manuals stop at 1985 .... 123 models....

are yall talking about the same thing I am ?

That is the Minimum time before starting the engine..( regularly trying to start over the life of the engine before the light went out would place extra strain on the starter.)

Then they put the other information in so you could use it in extreme situations where trying it right after the light goes out does not work.

You watch your RPM and if it drops too much, quit pouring in the water! If you stall the engine, then you may have to remove the glow plugs to pump the water out. If you use a bottle with a restriction at the neck, like a dishwashing detergent bottle, you should be able to control how much water you put in!! NOTE- This was only to find out if stuck rings are the problem! I've come across this more than once! It works on gas engines, yes, but it will work on diesels too providing you have the engine at normal operating temperature before starting this procedure!! Dino Diesel will form carbon in the pre-combustion chamber, AND in the rings! If there is a noticeable improvement in compression, then you found one problem. As he stated, a valve adjustment has been made already. Holding the engine between 2500 and 3500 RPM should suffice to keep it from stalling. Remove the air cleaner, Don't worry about the turbo for now, you will not put enough water into it to do any damage! Start the engine, let it warm up to normal, and take your squirt bottle and feed in the water at the recommended RPM and watch your tailpipe. It will begin to puke out soot and carbon! Leathermang, I've had many diesels apart to inspect for wear and damage while in the development stage, most of which were available for Dodge! Cummins, NV, Detroit, NHC, and International Harvester to name a few. If you follow my instructions, your engine will be fine! This method was used often and with success and would facilitate the dissassembly process and give us a clue as to what was going on inside there. I agree that dissassembly is the best and only way to correct a worn out and mechanically defective engine, but if the compression has ANY significant rise, it is getting clogged with carbon. This could be from a overly rich fuel condition and/or worn parts! It's worth the test to find out. I've done this many times to Freightliners and Peterbilts with high mileage as well as others with no damage. Let us know what happens!

this sounds like a good way to bend a rod.

i wouldn't recommend this at all.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

"I wouldn't suggest doing this to a good engine" These were the first words of my post.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Well I do want to try this, but right now I'm 800 miles from my home in halifax, so I'll wait 'til next week when I'm home to do it.

Oh and I've tested my glow plug relay with a volt meter and it puts out 11.5 volts for 42 seconds then switches off. the glow plug dash light switches off much sooner, after about 10 seconds. This I believe is as it should be, and yes often in freezing temperatures I'll glow them twice back to back before engaging the starter - manuals be damned!

Does the manual state "that is the minimum time before starting the engine"?? I don't believe that it does. We, therefore, have gleaned additional info regarding the start procedure for these engines.......info that is not in the manual.

In similar manner to the 35 second glow timer on the relay........also not mentioned in the manual.........the FSM is simply a very good guide........it's nowhere near perfect.

I don't usually take well to some yahoo who insults both my chosen profession and my main interest in the same comment!!!

First......The following is quoted directly from....

Diesel Engine Reference Book
Edited by LRC Lilly
Published by Butterworths
London, Boston, Durban, Singapore,
Sydney, Toronto, Wellington
in 1984

14.6.5 Special Starting Fuels

The starting aids described so far are all means of increasing the temperature of the air in the cylinder of a diesel engine at the end of the compression stroke, so that it will be satisfactorily above the self-ignition temperature of the diesel fuel employed, at the lowest ambient air temperature at which the engine will be required to operate. The alternative approach is to employ a fuel for cold starting the diesel engine, which has a self-ignition temperature below the temperature of the air in the cylinder at the end of the compression stroke, when starting a completely ‘cold’ engine at the minimum ambient air temperature at which it will be required to start.
The starting fuels employed are usually ether-based but because ether itself produces an undesirably high rate of pressure rise during combustion in the engine cylinder and has virtually no inherent lubricating properties, appropriate additives are included in the formulation of the fuel to protect the engine against the effects of these undesirable characteristics. This form of starting aid is now widely used and in it’s simplest form is an aerosol container marketed under such trade names Aerostart, Gasomatic, and Quickstart. Some fluid from the aerosol is sprayed into the air filter or air intake while the engine is being cranked. This is effective as a means of obtaining a means of a cold start under occasionally extreme conditions but, for general use a more precise control of the process is highly desirable.

.......this section goes on to explain sever automated means of controling the process......I inserted the bold print, not the publisher.....

Besides holding a USCG Chief Engineer Steam Unlimited Horsepower license....where I learned a while bunch about condensing vapors.....and those sprayed in "starting fluid vapors" will condense upon the cold surfaces of the cylinder walls......

I also hold a USCG Chief Engineer Motor Unlimited Horsepower license (please note that this also covers Gas Turbines).....where I learned a whole bunch about the design, operation, maintenance, and repair of all sizes of diesel engines.....I am not a MB Diesel Expert.....but a 50-150 hp high speed MB diesel would be covered.....

I have also been to Antarctica and Greenland aboard a Diesel Ship......so I think I have a bit of experience with cold weather, and diesel engines.....

I was also trained on Diesel Engines by a crew of German Diesel Engineers...and most of my Diesel engine experience is with German built equipment.....

From my personal experience, it is not a good idea to use starting fluids as a general usage starting aid.....excepting in emergencies.....

Aboard ship.....a can of starting fluid was sometimes kept in the Lifeboat Diesel toolbox.....and a can was generally kept in the Emergency Diesel Generator Room.....for use in Emergencies......

In my humble opinion, anyone who relies on Starting Fluids is lazy, and lax in their preventative maintenance program.....

Now sir, please state your credentials, if any!!!

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

My '82SD glowplug relay kicks off after about 30 or so seconds (617/126). I've timed it with a voltmeter attached to the leads. Also, if it's quiet enough around the car, I can hear the loud "thunk" when it shuts off.

Don't know if 123s are different.

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1998 E300 +310,000K
1996 E300 +460,000K

In all actuality, piston rings are pressed against the cylinder wall by the gasses of combustion......the spring in the ring is there to initially hold it against the cylinder wall.....but in piston and ring design....the gasses of the combustion process are directed behind the piston ring and due to minute differences in area.....they exert a force that presses the ring against the cylinder wall.....

I really don't feel like looking this up and typing a whole paragraph on the exact design principles.....but I will if I must...!!!

So, if carbon is allowed to build up in piston ring groves, it inhibits the ability of the piston ring to seal the combustion chamber.......

carbon deposits in ring groves cause several other problems....like stuck rings....but also eventually deform the ring groves, and over time actually change the amount of force available (from the combustion gasses working against the inner side of the piston ring) to press the ring against the cylinder wall......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

another reason the rings fail to maintain contact with the cylinder is the cylinder itself gets worn out of shape, or grooves from carbon deposits get worn into it.
John

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Like most things on these cars there were several ' editions' .
The reason your description has the " or so" in it is because the glow plug light time is supposed to be influenced by the "temperature of the engine and ambient air " through a sensing circuit .

" When the glow system is switched on , each glow plug is subject to a current of approx 20 amps ( peak pluse of approx 40 amps).
Under the influence of increasing heat , the inherent resistance of the glow plug increases and will limit the current to approx 8 amps. "

" After a glow period of approx 20 seconds a heater pencil element temperature of 900 degree C / 1652 degrees F will be attained, after approx. 50 seconds the max temperature will be 1080 degrees C/ 1976 degrees F. "

Safety Shutoff
" If there is no start following indication of ready - to -start condition , the glow current is interrupted by the safety shutoff, after 90+20 seconds for model year 1978/79, after 50+10 seconds for model year 1980. "

Sometime around 1981 they took out the coolant temperature sensing and only have the ambient air sensor.... but in the description of the fault sensing indicator....as when one or more pencil heating elements fail .... it says :

"A fault in the preglow system is indicated by the preglow indicator lamp not lighting up when the key is actuated in position " 2".
In the event of unfavorable tolerances of the pencil element glow plugs or of the Reed relay (d), response of the fault indicator only after two pencil element glow plugs are defective is allowed"

".... If the balance of the magnetic fields is interrupted by the failure of one or several pencil element glow plugs, the Reed contact will close and the electronic unit (b) will be activated.

The preglow indicator lamp will switch off immediately and will therefore not light up when preglowing starts. "

That last sentence indicates that the light and the power to the glow plugs are not tied together. The glow plugs can be heating even though 1. the light ( by being off or flashing) is trying to indicate system maintenance is needed ( more than one glow plug has failed ) ...or the light is burned out.
This also makes sense in terms of default planning by the engineers... would they have a system which could cause the car to not start due to an ' advisory' light system being broken.. or would the logic flowchart give the last word to the vehicle operator and operation of the key ? Notice that when I quoted the time for glow plug continueing to heat up that I was using the lower more conservative time... the 50+10 seconds... when I said " up to a minute" ....

"Lux" has a 1982 model vehicle.

The glow plugs cycle for 35 seconds.

The manual is incorrect.

You are incorrect when you state to leave the plugs on for one single cycle for 1 minute.

Sorry Greg, your reliance on the manual has failed you this time.

Sometimes the experience of others will trump the manual.

No, not easy, a real PITA on diesels and gassers, not to mention time consuming, but better than paying some shop to do the same testing, and better than tearing into the wrong part of the engine.

On diesel I prefer to add oil through the GP hole. Gassers is always the spark plug hole. I also use the GP hole for the compression testing. I use an old metal oil can with the small flexible spout to add oil for compression testing. I only add oil if the initial test results in one or two cylinders with lower reading than the others.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K