'90 Taurus problems
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Senior User
Joined: Aug 2003
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From: Rocky Mountains
'90 Taurus problems
I gave my old '90 Taurus to my grand daughter. It has a 3 liter, auto tranny, and suddenly it quit running. They live in the mountains at about the 6000 ft. level. When I was visiting I read the codes and found it has a bad ignition control module on the distributor. We replaced that unit with a new one and it starts and runs as long as you give it gas, but it will not idle. I had to return home but a friend of theirs had the same problem with his Taurus and traced it to his MAP (Manifold Absolute Pressure) sensor. They disconnected the vacuum line going to MAP sensor on their Taurus and it idles properly. Now I'm really confused. I would have thought disconnecting the vacuum line would have stalled the engine. They are now trying to get the MAP sensor tested, but why does the engine idle properly with the vacuum line disconnected? Everything seems backwards here. Any ideas will be appreciated. I understand one of the functions of the MAP sensor is to compensate the engine for altitude adjustment. Do you suppose there's a connection with them being at the 6000 ft. level?
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Senior User
Joined: Aug 2003
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From: Rocky Mountains
I was told by an auto parts store that when you disable certain sensors the computer sometimes goes into a fail safe mode and will enable the engine to run on some preset settings. This sometimes allows you to get the vehicle back home or to a garage so you can repair the problem. Has anyone else heard that explanation?
Tuned
Joined: May 2004
Posts: 334
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I believe the MAP sensor sends a signal depending on load which would be low vacuum, and then the computer adjusts fuel and timing accordingly. With the vacuum line off, the MAP is sensing no or low vacuum so computer sends more fuel. This will make up for you not having to give it gas and still run. Maybe it is the TPS, or Throttle Air Bypass Valve ( I think Ford uses this instead of Idle Air Control Valve. I don't remember if you said there were codes or not. You might see if there are any codes set. Cheers
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