Also note that the hand priming pump only moves fuel into the injection
pump, NOT out the injection lines to the injectors.  You operate the
priming pump about 50 to 70 times to prime the injection pump; you will
know that it is primed when the noise changes and the pump action firms
up.

How does the car run once you get it started?  Can you reach top speed
or does it lose power at highway speeds?  Watch the clear in-line filter
- is there a stream of bubbles entering?

-Max 

-----Original Message-----
From: mercedes-boun...@okiebenz.com
[mailto:mercedes-boun...@okiebenz.com] On Behalf Of Dieselhead
Sent: Friday, June 11, 2010 12:58 PM
To: Mercedes Discussion List
Subject: Re: [MBZ] Hard start problem returns

Try bleeding the fuel system at the filter (Top bolt, or line out) while
you pump the primer.  It sounds like air is getting into the fuel system
somewhere.  A leak at the filter can cause a leak.  Bad copper seals in
the delivery valves can cause problems.

If you get air out at the filter, you have a leak.  95% of the time, I
find leaks in the hoses or clamps.  Someone on the list reported air
leak at the filter.  I have had 2 cases of rusty cars having steel lines
rust through.


Fuel should leak out of the injector lines when you crack them.  They
should not be empty when you crack them.  Cracking the lines could
reduce backpressure somewhat to prime the plungers, but if you have a
good airtight fuel supply, cracking the lines has little or no
difference with a Bosch inline pump, after the injector lines have been
opened.  Newer cars have no provision for priming.  You just crank the
engine until it starts after replacing a IP or injectors, 
or replacing Injector lines.   Your 84 OM617 in not much different, 
except that it has a priming pump, which is a great aid for
troubleshooting the fuel lines.

>Thanks for the input.  No leaks at the pump and it is a newer style 
>pump.  Appears to to be pumping correctly however after manually 
>pumping 30 times or more the vehicle will not start.  After loosening 
>the injector lines at the injectors I pumped manually about 20 times 
>with no results after which I cranked with the starter and fuel began 
>flowing from the lines within 5 seconds.
>Tightened the lines back up and it started right away.
>It sounds like I have a pinhole leak somewhere that I am going to have 
>to track down, what a pain.
>
>Thanks again,
>Mike
>On Jun 11, 2010, at 9:52 AM, Dieselhead wrote:
>
>>Air leak in fuel lines.  He said it is not delivering fuel to the 
>>nozzles when the condition exists.  As an aside, Michael, you don't 
>>need to crack the injection lines.  Just prime it with the hand pump, 
>>then crank it.
>>
>>>I had a similar problem with an S10 pickup, it was something in the 
>>>ignition system but since your car is a diesel I guess it would not 
>>>be a hot ignition module...
>>>
>>>You sure it is fuel related?  Is the glow system working OK?  Glow 
>>>plug fuse?  Relay?  I replaced the relay on the 84 300SD with 
>>>whatever that new thing is Rusty sells, a fast glow relay or 
>>>something?  Or maybe it is just a new version of the same old.
>>>Whatever, the car starts much better now. (Hey, maybe that is like 
>>>the hot ignition module?)
>>>
>>>--R
>>>
>>>On 6/11/2010 9:24 AM, Mike Esh wrote:
>>>>1984 300D 290,000 miles and running strong.
>>>>Car starts very hard, sometimes not at all when I try to restart 
>>>>after driving long enough to get to full operating temperature.
>>>>If I restart within a few minutes it starts right up.  If I wait for

>>>>2 to hours it starts right up.  If I try to start up within an hour 
>>>>or two it will not start.  To get it to start I have to loosen 
>>>>injector lines and crank or manual pump until I get fuel to the 
>>>>injectors.  During the winter here in Michigan I had no problem 
>>>>whatsoever.  As soon as we hit 70 degrees plus it started acting up 
>>>>again.  Is this a problem with the injector pump or do I have holey 
>>>>hose somewhere in the system?
>>>>Thanks,
>>>>Mike
>>>>
>>>>_______________________________________
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>>>>
>>>
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>>>
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>>
>>
>>_______________________________________
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>>
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>
>
>_______________________________________
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>http://www.okiebenz.com/archive/
>
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