PeachParts Mercedes-Benz Forum - View Single Post

dpetryk · #41 01-09-2007, 07:05 AM

You are making things too complicated or you dont really understand what you are doing. Setting these things is simple. It goes like this - Set your duty cycle at idle or at 2000 rpm. Your choice. Once it is set leave it alone. If the duty cycle varies a great deal between idle and 2000 - 2500 rpm then there is something else wrong. Things like - vacuum leak, fuel distributor, fuel pressure, EHA, airflow sensor pot and on and on. You can adjust the mixture till the cows come home nothing is going to change until you find the root cause of the problem. The ECU (engine control unit) is responsible for enriching the mixture when accelerating. It uses a signal from the air flow sensor pot. Yours is probably shot. Stop fooling with the mixture control and look for the problem in other areas. The mixture control is not the problem and adjusting it will not compensate for other problems.

You need to have a good understanding of the fuel management system for these engines and then armed with that knowledge use your observation and diagnostic skills to determine where the problem is.

To answer some of your more recent questions - yes the plate must not scrape the air horn. Must be centered properly before anything else is done. - The bolt in the center of the plate - loosten it, center the plate, then tighten it. Very simple. The fuel pressure in this system is no more than 100 psi. So your 600 psi guages will work without problems but it would be difficult to accurately read the numbers you are looking for. You need to follow the MB proceedure outlined in the service manuals for checking the pressures.