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Old 08-07-2003, 10:33 AM
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Mike Murrell Mike Murrell is offline
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Join Date: Feb 2000
Posts: 2,359

If your car has a 1989 M103 engine, a good independent should be able to resolve the problem without OBD equipment. This comment is not intended as a slur against MB dealers.

I may stand corrected, but I do not believe OBD was around in 1989, at least not on the '89 M103.

An ignition scope could be used to check ignition.

Steve Brotherton's article on engine mgt. is also quite useful.
One needs TWO multimeters. One to test EHA current and one for the X11 diagnostic port. You'll want to use a multimeter with duty cycle capabilities for the X11 port. The EHA current test may be done with a std. no-frills multimeter; however, it must be able to read milliamp.

By the way, the EHA test harness that was $20 a few months ago is now close to $40.
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC

Last edited by Mike Murrell; 08-07-2003 at 11:21 AM.
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