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86 560 sl running very rich

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I replaced my fuel distributer with a used one, the 2 cylinders that were not working before are now working. I did not know how to adjust the EHA valve (black box on side), just used the one that came with fuel distributor. However, My car is running very rich, can you adjust the EHA, how do you do it, where do I start to diganose, I disconnected the cold start injector it made no difference. If i pull off one of the vacumn hoses it runs faster but not as rich, with the extra air. Can you identify the usual list of suspects to investigate. It starts right up, idles nicely (800rpm) has plenty of power, just running VERY RICH, with clouds of black exhaust.

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2005 E55 AMG Wagon
1996 S600
1992 500E
1991 560SEC
1987 300TDT
1986 560SEL
Re: 86 560 sl running very rich

Yes, you can. Remove the EHA, on the back is a brass flat head screw. Remove said screw and you'll find a 2.5mm hex. Make adjustments in SMALL INCREMENTS to the Left for Lean, Right for Rich..just like CO.

You should Really have a duty cycle meter hooked up while doing this..ideally an a/f ratio meter..

Keep track of how far you adjust the hex.. If you can't get it to run right you should check milivolts @ the EHA..and differential pressure b/w your upper and lower chambers in the fuel distro..

Jonathan

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Now playing: The Beatles - Revolution
via FoxyTunes

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Jonathan Hodgman Blue Ridge MB
http://www.blueridgemb.com
Offering Enthusiast Service, Restoration and Tuning.
(404)805-1357
2005 E55 Estate 2003 CL500, 93 500E Euro, 93 500E Brumos, 91 560SEC ECE, 91 500SL Euro,  87 AMG Hammer Wagon & Sedan 86 560SEL AMG 6.0L 32V,

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Re: 86 560 sl running very rich

Thankyou for the info, prior to your posting I was considering the mixture control adjustment, but did not think that the mixture adj would provide that much adjustment to overcome the rich mixture I have...stay tuned. thanks!

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Re: 86 560 sl running very rich

What exactly doe the EHA valve do?

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romank's picture
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1978 450SLC
Re: 86 560 sl running very rich

Check out this site and look at the FAQ and Blog especially the information about the lower chamber. This should give you a good understanding.

http://www.cisflowtech.com/

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1996 S600
1992 500E
1991 560SEC
1987 300TDT
1986 560SEL
Re: 86 560 sl running very rich

You can Readily get the mixture so far out of whack that the car won't start...never mind run! It's easy to do...pita to fix..

Jonathan

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Jonathan Hodgman Blue Ridge MB
http://www.blueridgemb.com
Offering Enthusiast Service, Restoration and Tuning.
(404)805-1357
2005 E55 Estate 2003 CL500, 93 500E Euro, 93 500E Brumos, 91 560SEC ECE, 91 500SL Euro,  87 AMG Hammer Wagon & Sedan 86 560SEL AMG 6.0L 32V,

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1982 380SL
1978 450SLC
Re: 86 560 sl running very rich

The best way out of that jam is to jumper the fuel pump relay and then adjust the AF mixture screw rich until you hear the injectors sing, then back off about a 1/4 turn. Replace the relay and it will start and run and then you can get it to rough tune by working the AF mixture rich until it starts to stumble, then go lean until it stumbles and find the mid point. From there it will run ok but will need the fine tuning to get the mixture dialed in.

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Re: 86 560 sl running very rich

Well after replacing my fuel distributer, and it running rich, I thought I might replace the EHA valve with the orig one from my bad fuel distributer, it started and ran, same sysmtoms, but when I went out to start it again a hour later, it would not start....no bother I put on the old EHA....same problem...ugh...any ideas out there?

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Lilburn, GA
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2005 E55 AMG Wagon
1996 S600
1992 500E
1991 560SEC
1987 300TDT
1986 560SEL
Re: 86 560 sl running very rich

You need to check your duty cycle/lambda, see if you can get that closer and then fiddle w/ your EHA.

I'm wagering the CO was fiddled w/ quite a bit before you replaced the FD..

Jonathan
]

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Now playing: Squirrel Nut Zippers - Anything But Love
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__________________

Jonathan Hodgman Blue Ridge MB
http://www.blueridgemb.com
Offering Enthusiast Service, Restoration and Tuning.
(404)805-1357
2005 E55 Estate 2003 CL500, 93 500E Euro, 93 500E Brumos, 91 560SEC ECE, 91 500SL Euro,  87 AMG Hammer Wagon & Sedan 86 560SEL AMG 6.0L 32V,

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