Date registered: Jun 2004
Mentioned: 1 Post(s)
Quoted: 5 Post(s)
The best idea is to have a spare MAP sensor( I have a couple ) which you keep aside in a box.I swap them onto cars which are running rough,if it cures bad running , I fit a good second hand one from ANY D Jet equipped merc,they are all the same!.
Generally the MAP sensor is a vacuum reading device with a coil inside which sends a reading to the ECU telling it the difference between the atmosphere(barometric) and the manifold pressure ( or lack of pressure depending on throttle position ) so the main symptom is really rich running.
To test is easy,just test the four teminals to see what sort of resistance you have. The diaphragm is stainless steel not rubber.
the terminals are marked 7 and 15 which should have 90 ohms resistance and terminals 8 and 10 which should be 350 ohms resistance.
The hose connection from the manifold to the MAP sensor must be perfect,fit a new hose if in doubt with hoseclips to ensure there are no leaks.
I note you mention the car had new injectors in the 90's,these injectors are bullet proof and can be cleaned with an ultrasonic cleaner .
They will last 30 plus years in normal use so I doubt if you have an injector fualt.
Has some one altered the idle mixture on the ECU?.Is the exhuast in good conditon.I have seen cars where the rear mufflers have collapsed inside ,not enough to block completely but enough to jam up the exhaust.
Last edited by mercmad6.3; 07-16-2006 at 05:23 AM.