[W126 Coupe] rough idle

[Tim Graney]

No I did not mic out the timing. I set the timing using the marks on the
cam. The passenger side cam was set with the mark just behind the cam
mark. Compression was fine both hot and cold...I forget what the numbers
were but they were even

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Jonathan
Sent: Thursday, August 09, 2007 3:16 PM
To: Mercedes Coupes Mailing Lists
Subject: Re: [W126 Coupe] rough idle


How did you set your timing?  If you just went off the timing marks on
the cams chances are it's not quite Spot on..  You need to mic it out w/
a mechanical lifter to Really know when things are dead on.

How are your compression numbers cold vs. warm.

Jonathan

Tim Graney wrote: 

Thanks...I replaced the chain and the tensioner and all the guide rails.
I do have some of the offset keys. I will give that some thought

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of __
Sent: Thursday, August 09, 2007 1:37 PM
To: 'Mercedes Coupes Mailing Lists'
Subject: Re: [W126 Coupe] rough idle



Howdy Tim, I once corrected a cold-rough idle problem by using an offset
Woodruff key on the right side camshaft.  It compensated for a bit of
chain stretch.

 

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Tim Graney
Sent: Thursday, August 09, 2007 11:53 AM
To: 'mbcoupes'
Subject: [W126 Coupe] rough idle

 

Here is a question for all you guru's out there. I have a 1985 500SEC
Euro AMG which I have pretty much replaced every top part on the engine
and it still idles rough when it is cold . I replace all the elements
that control the idle. The box, the valve, the fuel controller, warm up
regulator. It starts right up and idles to around 850 RPM nice and
smooth then starts to stumble a little bit like it is running fat. It
runs fine once you take off but stumbles a bit unitl it reaches
operating temp. As soon as it reaches 80C it smooths out and runs and
idles perfectly at 500RPM. I replaced all the sensors on the motor. The
only two I have not replaced are the two thermo time switches. I also
did the heads and replaced all the hydraulic compensators and lash caps
along with all new valves and springs. I just cleaned the the surface of
the heads about .002 to give a nice mating surface. All the wires have
been replaced. New Cap, New Rotor. I have adjusted the fuel mixture ad
nauseum. I use a vacuum gauge and a exhaust gas analyzer and like I said
it run tits when warm but crap when cold. Any Ideas?



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1996 S600 Euro "Scharnhorst"

1991 560 SEC Full Euro ECE (for sale)

1991 560 SEC 226Hp/271ft/lbs (TT conversion IP)

1988 300 TE

1989 560 SEC AMG (Mech.lifter/radical cam conv.)

1986 560 SEL 6.0L 32V AMG

1980 280 SE Euro

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