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  #1  
Old 10-14-2001, 02:14 PM
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Join Date: Nov 2000
Location: Los Angeles, CA/ Hilo, HI
Posts: 92
Mixture adjustment on LH injection system-Is it possible?

My '92 400E is running a bit on the rich side, smells like rotten eggs at times, but not all the times and I was wondering if it is possible to manually adjust the mixture as its possible on the KE/CIS injection system (with a 3mm T-wrench). I replaced the oxygen sensor recently and am now looking at other possible problems with the injection system. I need to get the car up to CA emmissions specs. Any suggestions?
Thanks in advance,
F.J.
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F.J.
81 300 SD grey/palomino 168K miles
84 190E 2.3 black/grey 64K miles (wrecked)
85 190E 2.3 maroon/palomino 92K miles
88 300E desert red/palomino 204k miles
(made to look like a '94-95)
92 400E desert taupe/creme beige 120K miles
(converted to 94-95 E420 looks)
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  #2  
Old 10-14-2001, 07:03 PM
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Join Date: Mar 2000
Location: Gainesville FL
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Mixture hasn't been adjustable on a warm motor since the onset of closed loop lambda control in 1980. The only thing that was adjustable on the K or KE cars was the base mixture setting. Once set the idea was to have equal ability to correct electronically both lean and rich. If you adjusted that correct base mixture richer the cars system will correct back to lambda (the theoretically exactly proportional mixture of 14.7 to 1 air fuel ratio that equals the equation HC + O2 = CO2 + H2O with nothing left. If you continually correct richer you will eventually go beyond the cars ability to correct.

Any car running rich is NO LONGER functioning. All controls have been over-ridden. Well, as it happens, many people do that and the manufacturers were forced to build systems that automatically correct base positions. All of the LH, HFM and ME systems built since 1992 have been totally self-correcting to a point. That point causes many problems on the early cars as the factor of correction was about 15% both sides of the original fuel calculation. Later cars are allowed with software to correct as much as 32% each way.

If you are really running systematically rich then something has overpowered the system. With a scanner this correction factor can be read and reset, but the amount of correction isn't adjustable. It is also possible that the correction factor could be within limits and single cylinders are the problem. The correction factor gives the guidance here.
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Steve Brotherton
Continental Imports
Gainesville FL
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  #3  
Old 10-14-2001, 09:26 PM
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Join Date: Nov 2000
Location: Los Angeles, CA/ Hilo, HI
Posts: 92
Thanks for the highly educational reply.
I assume there is nothing I can do myself, but have a MB tech check it out, correct?!
Thanks a lot again,
F.J.
__________________
F.J.
81 300 SD grey/palomino 168K miles
84 190E 2.3 black/grey 64K miles (wrecked)
85 190E 2.3 maroon/palomino 92K miles
88 300E desert red/palomino 204k miles
(made to look like a '94-95)
92 400E desert taupe/creme beige 120K miles
(converted to 94-95 E420 looks)
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