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#1
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190E 2.3 mixture adjustment
Hello.
I have just bought a 190E 2.3 8valve (1992). The previous owner had the fuel system readjusted as the idle was low and sometimes it stalled. Then the idle went up to 1000rpm and the car run much better. However, it didn't pass the emissions check and had to lower it again, so now it stalls sometime and doesn't run as it should. I want to increase it a bit. He told me about a kind of adjustment with several positions, although the fuel distributor hex. screw sound more likely to me. Can I do it myself (I have an oscilloscope and can check the duty cycle signal or whatever in the diagnosis conector if you explain me how to do it). Is there any other adjustment in this car? Best regards. |
#2
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Print out the following web pages for your reference, and let us know if you have any questions or problems. Also search for discussions on mixture adjustment. There was one within the last couple of days.
www.landiss.com/mixture.htm Duke |
#3
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Thanks, I had that sheet already.
Then I should measure that waveform and then adjust the mixture with the screw so I get a 50% duty cycle at idle and at, say, 2500 rpm, is that correct? If I manage to do so, can I be sure that it will pass the COx emission test? (it does now)? Should that improve throotle response? A lot of thanks. That forum seems very useful. Sergio |
#4
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Look at the following thread:
http://www.peachparts.com/shopforum/showthread.php?threadid=90225&perpage=15&pagenumber=2 second page, my last response, which is the third from last post. It should start well and pass emissions. As far as "throttle response" is concerned, there will likely be no change. There's nothing wrong with the throttle response of these engines - it is essentially instantaneous, but the relatively soggy low end torque and lazy automatic transmission response can sometimes be misconstrued as "poor throttle response". Duke Last edited by Duke2.6; 03-30-2004 at 01:21 AM. |
#5
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Does the 190 come with a cat. converter?
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... Kerry 126 tailed by a 203, 129 leading the pack. |
#6
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Thanks for the info.
Now I have found some threads in this forum (very active and helpful, by the way). My 190e 2.3 8 valve (1992) does come with catalytic converter. That's what I will do. Please correct me if something is wront or bad interpreted: - Leave the car warm up to, say, 90 deg or so. - Check the pin-3 signal of the diagnostic connector with an oscilloscope for duty-cycle. - If it is not around 50%, I will touch the 3mm hex screw until it is: now a doubt: should I do this with or without the lambda probe connected (02 sensor)? - The idle should stabilize. Should it change the number of rpms? What is the good number? Now it is about 700, but I think that's a bit low, what about 850-900? Any help will be very appreciated. Best regards, Sergio |
#7
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One more doubt about the procedure you have pointed to:
"3) Detach the purge line at the electric switchover valve and seal. On my car, this valve is mounted on the inner wall of the left fender, adjacent to the ABS controller. The subject line is black tubing with white stripes." What is that? Is it related to automatic transmission? If so, do I have to remove something if I have manual transmission? Best regards and sorry for so many questions. |
#8
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I really like the EHA current for this mixture correction. The reason is that whatever happens, happens at the EHA.
I am pretty certain your above steps are about to screw with you. I'm a little fuzzy here but certain cars and I think yours might be one of them require the pin#3 diagnostic to be turned on from the other diagnostic connection by the battery. If you have one of those models you will get a zero reading I think till its turned on. The EHA is still working during these situations so it is always useable.
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
#9
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A lot of thanks.
How can I activate that duty-cycle reading? Best regards, Sergio |
#10
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Ooops. Another question. I have read somewhere that the idle speed is adjusted in some CIS systems with a 7mm separate screw. Is this correct or touching the 3mm hex will affect my idle rpms?
Thanks |
#11
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Only the first 190s had adjustable idle speed. The amount of air entering the engine is what controls engine speed. The allen adjustment at the fuel distributor does mixture.
To start the diagnostic at the passenger side connector use the code retrieval initiation of a two second grounding impulse to hole number 3. Go to the DIY article about evaluating engine controls for more precise discussion of the diagnostic trigger.
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
#12
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Mmmmm.
Thanks. Sorry for asking too much. You mean that I can't adjust the idle to be faster? Or that adjusting the mixture will affect it? Besides, where exactly is located the "passenger side connector"? Is it inside the cabin? Sorry, I would be very happy if I could have a Service CD, I wouldn't bother you so much ;-) Best regards |
#13
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The other connector is in front of the battery on the back side of the engine bulkhead.
The idle is automatically controlled. If it is wrong it is broke. Mixture doesn't change rpm untill it is so bad the engine runs poorly and thus slower.
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
#14
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Question for the knowlegables out there
OK, so I have a European version of the 190e, first one to come out or something like that and it never had an O2 sensor. This should explain why pin number 3 on the X11 connector is missing (hole there but no metal connector).
So I brought it over here and they (US garage) "converted it" to US specs. They drilled a hole in my exhaust pipe and welded an O2 sensor in there (perminantly - try to replace that one easily) and connected it somewhere, not sure. I can follow the wire to see where it goes if that will help... Is it really working for me or was it some sort of a kludge job since the car probably doesn't have all the systems necessary for everything to work right? Also, maybe this O2 sensor is bad. Can I tell and God forbid it is I can't just unscrew it out, does it hurt anything if I just ignore it? BUT, if I have no pin 3 in X11 then I have no Lambda on/off ration that you guys are talking about. I also have no "cigarette" box on the battery side with the OVRelay in there, mine I found on the left side of the fender with only 1 fuse on top. WELL, that aside, HOW do I adjust my mixture on my car besides running it at idle, turning the adjustment until it runs rough, then turning it until it runs smooth and fast, and then picking somewhere in between? The has to be a better way... Stevebfl, can you please comment and help! Detail would be most appreciated as sometimes its like a puzzle trying to understand what people are talking about on this board and having to search and read other posts for more details on individual terms. Thanks!!! -=>Raja.
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1983 MB 190E, bought from Germany and shipped to the US in 1986. |
#15
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I would suggest following the wire from the sensor and see where it goes. There were a multitude of ways people created lambda control. Before you try and understand lambda control you might as well figure out if and how they do it.
One way that was done was to take the coolant temp sensor and cut the wire. They would feed both ends into a new box that would read the O2 sensor and change the effective resistance of the temp sensor to alter mixture. It was a terrible method and never stayed in adjustment for any length of time. Some cars would actually just need to have the O2 sensor hooked to the original computer and some people changed the controllers and added the O2 sensor. You should determine what you have and go from there.
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
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