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  #1  
Old 06-23-2007, 03:36 PM
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Whats the difference?

My 77 300d is hard to start and requires a couple pumps of the accelerator in order to start. Would you recommend replacing spark plugs or the pre-glow time relay??

Thanks for anything.

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  #2  
Old 06-23-2007, 03:57 PM
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Check GLOW PLUGS with an ohm meter, should read low. You have the loop style. Check fuse in relay, I think located under dash.
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  #3  
Old 06-23-2007, 04:05 PM
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You could also have air leaking into the fuel system, usually through IP lift pump.
I can guarantee it isn't the spark plugs, though.....
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  #4  
Old 06-23-2007, 05:10 PM
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While you are at it, be sure to replace the rotor and distributor cap.
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  #5  
Old 06-23-2007, 06:21 PM
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he'll need a new coil to to go with the spark plugs. you want lots of juice to run em.
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  #6  
Old 06-23-2007, 07:13 PM
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You evil ones, give the guy a brake...
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  #7  
Old 06-23-2007, 07:27 PM
ForcedInduction
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Quote:
Originally Posted by mouramen View Post
You evil ones, give the guy a brake...
Sorry, the first two responses pretty well covered what's most likely wrong. A bad glowplug and/or air leaking into the fuel lines.
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  #8  
Old 06-24-2007, 02:11 AM
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oops

sorry bout that, glow plugs. i was def. not thinking
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  #9  
Old 06-24-2007, 02:51 AM
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Keep us posted.
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  #10  
Old 06-24-2007, 07:09 AM
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Talking To avoid sarcastic replies.....

Please be aware that pumping the accelerator pedal does absolutely nothing on a Diesel.....

SB
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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
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  #11  
Old 06-24-2007, 11:17 AM
ForcedInduction
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Originally Posted by Shorebilly View Post
Please be aware that pumping the accelerator pedal does absolutely nothing on a Diesel.....
Right, it will only help if you hold it down while you crank the starter.
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  #12  
Old 06-24-2007, 11:36 AM
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Quote:
Originally Posted by Shorebilly View Post
Please be aware that pumping the accelerator pedal does absolutely nothing on a Diesel.....

SB
Correct, that would only flood the carburetor.
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  #13  
Old 06-24-2007, 03:40 PM
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Arrow Yo Forced.....

If all is working as designed....holding the pedal to the metal while starting does not do much for you either.....the governor inside of the FIP will be at "full rack" when the engine is stopped....and only moves off of "full rack" when the engine speed comes up to the speed set by the accelerator pedal....

there is a set of flyweights and a spring that actually control the fuel rack.....thru a system of levers "suitable linkage"

SB
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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
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  #14  
Old 06-24-2007, 03:46 PM
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Quote:
Originally Posted by Shorebilly View Post
If all is working as designed....holding the pedal to the metal while starting does not do much for you either.....the governor inside of the FIP will be at "full rack" when the engine is stopped....and only moves off of "full rack" when the engine speed comes up to the speed set by the accelerator pedal....
Incorrect, I suggest you read the owners manual and the Bosch highlights manual.
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  #15  
Old 06-24-2007, 04:08 PM
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Talking Don't know that book.....

Quote:
Originally Posted by ForcedInduction View Post
Incorrect, I suggest you read the owners manual and the Bosch highlights manual.
Will check the owners manual.....

My manual says: Depress accelerator halfway and turn idle speed adjuster counterclockwise to the stop. Then release accelerator (only on 240D) It has a scenario for Ambient temp exceeding 0*C / +32*F with no mention of the Accelerator....and a scenario for Ambient Temperature below 0*C / 32*F where it tells you to depress the accelerator.......and release accelerator slowly.....

I would think that it is MB's intent to add a little extra fuel for cold starting....because as I said as the engine speed increases the fuel rack closes to it's setpoint....which would be idle with no pressure on pedal....

don't know about a "Bosch Highlights Manual" ...but what I do know is.....after the engine stop device pulls the rack....it is in fact attached to the rack itself....but allows for rack movement....to full stop.....and the engine stops......the fuel rack will return to full fuel for starting.....the accelerator is attached to a lever on the backside of the FIP....that lever is connected inside to a set of "suitable linkage", involving a couple of pivot points and levers.....a yoke sits in a collar that is moved by the the flyweights acting against the speeder spring....this yoke moves a part of the linkage......and will move the fuel rack to Full when the set speed (by accelerator pedal) is greater than engine speed.....at rest the rack should be at Full rack until the engine gets close to the set speed of the pedal...with no movement of the pedal this will be "Idle Speed"......actual difference in speed where the fuel rack begins to close is determined by a fulcrum point and another spring and some lever action.....

Please remember that it has been nearly 10 years since I did this for a living....so I may be off a bit on this description.....but I will stand by "Full Rack at Start regardless of accelerator position.....

SB

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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

Last edited by Shorebilly; 06-24-2007 at 04:25 PM. Reason: additional commentary
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