Constant Barometric correction having no effect

[Nigep]

I am running a standard MPX4250AP Map Sensor but wanted to add a second for barometric correction in my Speed Density setup.


Using this circuit


I mounted an identical sensor to the case lid and wired it up. I`ve removed the heatshrink on the wires / components to try and fault find. Obviously I`ll be refitting them once I find why this isn`t working.


Configured to use the secondary sensor. I BURNED and power-cycled the ECU after changing this setting.


RED is +5V, Green is 0V and Yellow is signal.

You can see I`ve connected the Signal wire to JS5 as instructed


I measured with a voltmeter and from 0V to Signal, I get around 1.7V at atmospheric pressure. If I add a tube to the sensor and blow / suck, the voltage reading changes, going down as I suck and up if I blow.

I sucked on the pipe conencted to the MAIN Map sensor, to produce -7.7psi.


Whilst sucking and producing around -5psi, I power cycled the ECU. This reset the Engine VAC/Boost to zero and set the Barometer to 70kps (approx -5psi) The limit I`ve set should limit this to 95kpa, but it doesn`t.



Can someone help please ? The ECU isn`t seeing the second MAP reading and is still taking the barometric reading off the Original MAP Sensor. I`m lost.

[Nigep]

Can I add anymore information that would help someone help me diagnose this please ?

[slow_hemi6]

Would it have something to do with Engine Constants > Barometric correction "Off" ?

[Nigep]

Would it have something to do with Engine Constants > Barometric correction "Off" ?

Possibly.....


I have no idea why that was off, but I turned it back on, power cycled the ECU and the 2nd MAP Sensor worked !!

Sucking / blowing on the 2nd sensor changed the barometric reading, from 95 to 105 (as limited by me in the settings). Increasing that range from 50 to 150 allowed the BARO reading to change from 50 to 150 as I applied pressure / vac.

MANY Thanks to slow_hemi6, I have no idea when that was turned off, but it just shows that adding the MSQ really does help even if you think it doesn`t.

[slow_hemi6]

Sometimes it just needs a fresh set of eyes. Always good when it's an easy fix.