Okay, heres the deal. My 1987 190e 2.3-16V sputters(engine wants to die) when I am driving in any gear at almost any constant speed. Accelerating only sputters for about 1 second then accelerates fine, but then when i hit the speed I want, it starts to sputter again. It has been doing this for a while now and I am stumped. Could it be a faulty o2 sensor doing that? Only reason is because the sensor light comes on, then turns off after a while. Any help would be appreciated. Thanks!

Your symptoms are pretty vague-you might start out with a systematic check of the fuel injection and ignition systems. Steve Brotherton (stevbfl) has written many posts about troubleshooting the injection system, do a search and read his article in the diy section. You might have more luck with more specific information that would result from some time with a duty cycle meter/multimeter.

cheers,
dan r

Is this the car that's getting less than 230 miles a tank? Sound like you have some injection/mixture issues.

As Dan stated, if you have a volt meter, you could check the X11 pin and see if any fault codes are present and that might point you in a direction. Do a search on duty cycle or X11.

Tinker

yes this is the car that is getting about 230miles to a tank of fuel. The sputtering only seems to happen when it is pretty cold. I have used water remover thinking it is that but it isnt. I will check that pin on friday when i get a chance. It was above zero today and it wasnt sputtering at all. Very odd. I still havent changed the o2 sensor yet as it has been monstrously cold here lately. Friday is going to be a warm day so the I will change it and hope for the best. Thanks for the help.

Check mixture. Check O2 using a VOM put the red lead on the connected single lead of the O2 with engine running and black to ground. Should read above .5V and fluctuate while idling. Range is somwhere under 1 V but of course above 0V. Most run around .7V. Also clean your AFM and Idle Control Valve with some nice Carb Cleaner and a rag. Run some fuel injector cleaner. Also check all Vacuum connections and the Rubber Boot between the AFM and the Throttle Body. When cold if that boot is just starting to crack it will suck extra air in and of course then lean the mixture due to the extra air.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Check the electrical contacts at your fuel pump relay. My car was doing just this and getting attrocious fuel mileage. I pulled the relay, cleaned all of the contacts on the relay and in the plug for the relay. Now I have reliable, consistent power, much improved economy and easier starts. For the record, my O2 light would flash when the car was acting up, despite a new O2 sensor. Since doing this, no more O2 light.

Also do the same for the OVP relay.

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Regards,

Mathieu J. Cama
Old World Automotive
Lawrenceville, GA
service@oldworldauto.com

Specializing in high caliber repair and mechanical restoration of vintage Mecedes-Benz.

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