MAP sensor issues.
Posted: Sat Mar 03, 2012 11:05 pm
First off, I'm new to this and am getting very overwhelmed.
I bought a ms2357-c assembled ms-II V3.57 WITH Ford TFI mod and a 12' harness we made ourselves. If I turn on the ignition and check the map pressure it shows 94.2( I'm at 2k foot elevation) if I hook up a vacuum pump/gauge to it it reads correctly and seems fairly accurate. However once u turn on the motor the pressure drops to 42kpa and doesn't move, no matter if u give it gas, disconnect the hose, try putting the vacuum pump back on. Nothing changes map reading other then stalling the motor. If the motor drops below 500rpms it will read the map for a second then freeze up and stop moving again until it drops below 500rpm or the key is turned off then back on.
At first we thought it was just a sticky map sensor but To complicate things. I also have a msII that is a plug and play style with the small adaptor harness to go to the stock mustang wiring. If I put the new computer into the old truck it works fine. No MAP issues. if I put the old plug and play computer in this new truck the map sensor reads correctly BUT it won't advance the timing. (not even trigger offset) so it seems either computer can run my plug and play wiring harness but neither work on the new truck but they don't work in different ways. How is this possible ?
I bought a ms2357-c assembled ms-II V3.57 WITH Ford TFI mod and a 12' harness we made ourselves. If I turn on the ignition and check the map pressure it shows 94.2( I'm at 2k foot elevation) if I hook up a vacuum pump/gauge to it it reads correctly and seems fairly accurate. However once u turn on the motor the pressure drops to 42kpa and doesn't move, no matter if u give it gas, disconnect the hose, try putting the vacuum pump back on. Nothing changes map reading other then stalling the motor. If the motor drops below 500rpms it will read the map for a second then freeze up and stop moving again until it drops below 500rpm or the key is turned off then back on.
At first we thought it was just a sticky map sensor but To complicate things. I also have a msII that is a plug and play style with the small adaptor harness to go to the stock mustang wiring. If I put the new computer into the old truck it works fine. No MAP issues. if I put the old plug and play computer in this new truck the map sensor reads correctly BUT it won't advance the timing. (not even trigger offset) so it seems either computer can run my plug and play wiring harness but neither work on the new truck but they don't work in different ways. How is this possible ?