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Old 06-28-2016, 04:25 PM   #1
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Default Engine MAP does not move

I am trying to help a fellow enthusiast with his 1999 1.6 for which he bought a used MS-Labs Enhanced MS2 V5.5 ecu with 330F firmware. Upon powering the ecu TunerStudio gets a reading of engine MAP input. If I suck on the map hose when turning power on I will get a ~80 kPa reading. Power on while map in free air and 100kPa results. If I remove a jumper inside the ecu to disconnect the MAP sensor, it will read 10kPa which equals 0V in the calibrations. I also measured the MPX4250AP to be putting out correct voltages to the Microsquirt module.
Thus hardware seems to be working at least to some extent.

However, Engine MAP does not move from the initial reading. Attempts at running the engine lead to the fuel load staying constant 100% whatever the conditions. To further complicate the problem, even if the initial Engine MAP is measured to be 80%, fuel load will always stay at 100% (set to speed-density).
I tried reloading the firmware - which did not help. Engine constants are set to speed-density, secondary fuel load disabled, multiply map set on as usual, no barometric correction, MAP sample method is "use average", I have also tried various MAP averaging lag factors.

It almost seems like incorrect firmware or a bug. Maybe even something settings related...
The car was laying in a local tuning shop for 8 months without a solution. I thought I'd give it a try too. However, I am starting to run out of ideas. It is a shame to have such a neat and well featured ecu not working. The owner has invested a lot of work and money gathering/fabricating parts for a supercharger.

I have pm'd Reverant to send me a base map and to comment on whether to update the firmware. I am sure he will do when time permits. I am posting here because this could be something quite general MS settings related someone else has stumbled upon. msq attached if someone cares to take a look.
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File Type: msq MAP-problem.msq (99.7 KB, 26 views)
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Old 06-28-2016, 05:29 PM   #2
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where is the line to the map sensor coming from?
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Old 06-28-2016, 05:36 PM   #3
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MAP lines can get pinched/clogged/broken. You should be able to generate a lot of vacuum with your mouth (this is MIATAturbo.net, after all).

Also, on startup, there is an option to hold MAP constant (regardless of the real reading) for a period of time under the theory that MAP has large swings during the start phase. Might take a look at that and make sure it's not excessive. I have mine set to 2 seconds.

Last edited by hornetball; 06-28-2016 at 07:36 PM.
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Old 06-28-2016, 06:57 PM   #4
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Originally Posted by 18psi View Post
where is the line to the map sensor coming from?
Lol, my thoughts exactly. I've left the map line disconnected before. You sure do feel stupid when you figure out that's why the car is running so terrible. Some vacuum ports on the intake manifold won't give you a good reading either, maybe try a different spot.
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Old 06-28-2016, 09:33 PM   #5
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That '99 1.6 should be a return style fuel system. Therefore the default best place to attach the map line would be to Tee into the line between manifold and FPR.
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