Thread: 280SLeuro
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Old 06-06-2001, 06:25 PM
Posts: n/a
I found the problem with the 280SL, cutting out on accelerartion. You put me on the right track. I checked the MAP sensor and found a cold solder conection inside the unit. The car runs great now, nice and smooth, no misses.
Thanks for your help, M.C.Doc, cth350, Stevebfl. Some day I guess I well have to tell you the story about how I aguired my $2500. 280SL and grasped it out of the distructive hands of fate. Boyd
Originally posted by stevebfl
And the Map sensor is adjustable.

To verify the condition of the Map sensor, take your scope and hook it to the injector. Read the pulse width, while Key-on, Engine Off. To do this move the throttle by hand. You should get 20 injection pulses. Read the pulse width. Now get a hand held vacuum pump and pull 15 inches of vacuum on the Map sensor. You should get a pulse width less than half of the no vacuum test. Normal range of injection pulse width would be from around 3.0ms at idle vacuum to around 10ms at no vacuum.

The Map sensor works off an evacuated bellows that swells and contracts due to different vacuum placed on it. It moves an armature through to coils one an input and the other the output. If the evacuated chamber is corrupt then no motion comes and no enrichment gained.
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