[SloGN]

where are you getting the power for the MAP sensor? if you are using the factory map sensor location/wiring for your power and ground there is the problem.


The 5 volts and ground are tied into the tach and boost gauge. the tach and boost gauge has thee own 5 volt power supply that is not tied in with the other 5 volt power sources for the engine sensors.

what you need to do is pull a ground and a 5 volt wire from the tps. since those are coming from the fast ecu and those are a rugulated power source so they stay a constant 5 volts



i had about the same problem except my car when you would turn the headlights the car would go rich. What was happening was the headlights/dashlights would change the incoming voltage to the map sensor and that inturn would change the output voltage as well. the fast system seen that as a vac/kpa change int he engine and strt adding fuel accordingly.

so i got the checking it with a volt meter and sure enuff the voltage would change no matter what you turned on in the car the voltage would change at the map sensor. the lights affected it the most tho.

So with some more research the 5 volt power supply in the dash for the tach and boost gauge is not regulated. so a change in input voltage it would not correct for so the 5 volt out put would change also.


that would explain why there is so much inconstistansy in the tach/boost readings too i believe.


HTH sorry for the long post.