[W126 Coupe] rough idle

[Jonathan]

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
2006 Z4 3.0Si M-Spec

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