1. Autos

Your suggestion is on its way!

An email with a link to:


was emailed to:

Thanks for sharing About.com with others!

Questions and Answers

Mercedes Benz 190E Lost It's Power

Q. Dear Sir, I recently purchased a 1989 Mercedes Benz 190E 2.6 liter with high mileage, drove it back home which was about 250 miles. All was going fine, then I started repairs or more correctly performing preventive maintenance. I bought a K&N air filter, installed it and soon there after started having problems with the car not wanting to accelerate.

Mercedes Benz 190E Lost It's Power

It's as though it is running on one or two cylinders, can let up on gas pedal and eventually get the auto up to speed. As long as I am driving at highway speeds all seems to be okay, just some hesitation while on cruise control. As I get into city driving, the problem will reappear, a couple of times I have had to pull over and let the car sort of clear itself.

I suspect the injectors are partially the problem, just not sure how to test or where to get equipment to test injectors. I have installed K&N air filters on most every engine I have owned, their claim to fame is the ability to deliver greater quantities of air. If this is the case, could my air/fuel mixture now be so far off I will need to go back to a paper filter until I can have the air/fuel mixture adjusted?

Unfortunately, I discarded the old filter but would consider purchasing a new paper filter to confirm my theory or perhaps I can choke off the intake. I believe the car is well worth any repairs at this point in time as it drives as well as a new vehicle, quite remarkable considering the car's odometer reads 201,000 and it is no longer working.

Thanks for your assistance and I do enjoy reading the articles on your web site.



If this problem started when you replaced the air filter with the K&N air filter, then it is quite possible dirt or some other foreign matter got into the Air Flow Meter (AFM). The AFM is part of the fuel distributor.
Mercedes Benz 190E Lost It's Power

The fuel distributor meters the basic injection quantity to the individual engine cylinders. The fuel distributor uses the position of the air flow sensor plate as a measure of the amount of air drawn in by the engine. The position of the plate is transmitted to the control plunger by a lever.

Even with the increased air flow, the AFM will see it and adjust the mixture accordingly. But I guess it is possible that it can't compensate enough. Installing the correct air filter will determine this.

It's also possible that if something got stuck between the sensor plate and AFM body, that would cause the engine to run rich, which is what yours sounds like it is.

Checking the idle air/fuel mixture adjustment will require the use of the on/off ratio tester, Bosch KDJE-P 600.

Mercedes Benz 190E Lost It's Power

As an aside, Mercedes Benz does not recommend using the K&N air filter.

Additional Information provided courtesy of AllDATA

Back to Index
© 2003-2004 Vincent T. Ciulla

©2015 About.com. All rights reserved.