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-   -   Long cranking (http://www.peachparts.com/shopforum/tech-help/4800-long-cranking.html)

CMuc 07-21-1999 02:26 AM

I have an 87' 300e. When I start it first thing in the morning it takes 2 or 3 seconds to start. If I shut it off for up to 15 minutes it will start right up again. I go through this again at noon when I go for lunch and again when I go home for the day. Also the econ guage reads 1/4 to the right at idle. I put a vacuum guage on it and it only reads 10". is this possibly related? I personally rebuilt the engine two years ago complete (pistons,bearings,valve job) to pass our emission test. I hoped that this would rectify the long crank and low vacuum but I was wrong. Any suggestions? thanks

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Chris Muc
Auto mechanic
'87 300E 325,000 km

MB STARS 07-21-1999 01:27 PM

Check the adjustment,fuel pressure,air flow
sensor unit and cold start system.

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MB STARS Master Guild Technician,12 years MB tech
5 years independent shop owner

mbdoc 07-21-1999 07:40 PM

In most M.B. literaure they state 4sec crank time is normal for CIS-E fuel systems.

Benzmac 07-21-1999 09:05 PM

There is an advanced repair that adjusts the air plate static position. If you go too far, you have to remove the whole thing though. It should be left up to a tech.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM



CMuc 07-23-1999 03:21 AM

O.k. I will check those adjustments. Should the fuel distributor hold pressure? For how long? What about the low vacuum? I have been in other 87' 300Es and they start right up and econ guage "pinned" left. Is this guage in fact a vacuum guage? thanks! P.S. great site!

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Chris Muc
Auto mechanic
'87 300E 325,000 km

Benzmac 07-23-1999 10:14 PM

Yes it is a vacuum gauge. The low vacuum could be a result of a burned intake valve.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM



CMuc 07-23-1999 11:36 PM

The engine was recently rebuilt with a complete valve job etc... however the timing chain was not replaced, could that be a factor?

thanks


[This message has been edited by CMuc (edited 07-24-1999).]

mbdoc 07-24-1999 09:26 AM

Some times the installed valve height is too high after valve jobs, and on start-up the lifters hold the valves open. Could this be the reason that the ecno gauge isn't reacting right? M.B. offers smaller shims for the correct lifter position. I would be happy to send cranking time info (ie:4sec) being normal.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH



Benzmac 07-25-1999 09:45 PM

I have not seen a timing chain wear out on a 103 engine yet. MB DOC is right on the valve too tight theory.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM



CMuc 07-30-1999 01:12 AM

Today I timed the cranking and it was closer to 10s !!! I Thought it was shorter. I tested the fuel pressure to the fuel distributor and it was fine. As soon as I shut the car off it dropped to 0! Is this my problem? Is it a simple fix? As for the held open valves, I will perform a leak down test to verify and get back with the data. Thanks.

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Chris Muc
Auto mechanic
'87 300E 325,000 km


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