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justingsmith, UK Car Answer Team
Category: UK Car
Satisfied Customers: 18
Experience:  UK Car Expert
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MAP sensor..disconnected..the engine chokes, runs rough and rich

Resolved Question:

When I connect the MAP sensor vacuum line to the inlet manifold the engine wont start. When disconnected it will start and run but not that well. When reconnected whilst running the engine chokes, runs rough and rich. Whats the next step to sort this problem out?
Submitted: 9 years ago.
Category: UK Car
Expert:  justingsmith replied 9 years ago.
I had this happen some time ago, the engine would not start with the map connected?Very strange, but it did happen. Most people would think the crank angle sensor first but this was not the case.The MAP is a master in fuel delivery, if it is off, the entire fuel system is out of wack. most people are just not aware of how important the thing is. If the car runs better with it disconnected the ecm is dumping fuel. and nothing has more impact on fuel dilevery than the MAP in this stage( some meats might say the 02 sensor, or coolant sensor but not on old school fords)and defiantly not on start up! I would just replace the MAP, but there are simple tests you can do. First is make shure the old MAP holds vacuum. Hit me back if you need a full test.
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