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-   -   map sensor faulty reading?? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/map-sensor-faulty-reading-432108/)

ORX705 06-08-05 04:38 PM

map sensor faulty reading??
 
I just installed a power fc and noticed the factory boost sensor reading is not the same as the AVCR boost controller reading or the other boost gauge. The AVCR and PFC map sensors both run off the same vacuum line. I suspected it may have been a blocked inline filter so it was turfed and now they both run off the AVCR filter. No kinks, no cracks in the vacuum lines.

At idle the factory map sensor will read an extra 80mmHg or so of vacuum. But after recalling the peak values after WOT I got 0.44kg/cm^2 on the PFC and 0.58kg/m^2 on the AVCR. Meaning the PFC is underestimating boost and therefore possibly running lean.

Any ideas or should I just replace the expensive factory map sensor?

rynberg 06-08-05 04:47 PM

It's been known for years that the Commander displays boost readings too low, due to an internal error. The PFC still uses the correct boost for use with the fuel and timing maps, it's just a display error.

ORX705 06-08-05 05:19 PM

thanks rynberg
i can live with that

POS7 06-08-05 05:32 PM


Originally Posted by rynberg
It's been known for years that the Commander displays boost readings too low, due to an internal error. The PFC still uses the correct boost for use with the fuel and timing maps, it's just a display error.

I've heard about this, but I wasn't too sure if it was true or not. My commander seems to be functioning fine. I was using the PFC when my car was fully stock and it was reading the .69-.55-.55 pattern, therefore I think its accurate.

Now, I get a .69-.55-.69 pattern normally, but if I downshift and punch it, I get a .8-.7-.8 pattern as read on the commander. I'm guessing that if I want a more consistent .8-.7-.8 pattern, I'll need to increase the max duty cycle for the injectors.

My only power mods are gutted stock intake and downpipe.

I'm wondering if there are different software/hardware editions and if that makes a difference. I have my commander/pfc box and will try to post my version.

ORX705 06-08-05 05:43 PM

in that case i have

PFC - 5.08
and commader 3 - 5.01A

rynberg 06-08-05 06:24 PM

The error gets worse as you go higher in boost. It may be pretty close at 7-8 psi but gets fairly off at 14+ psi. It will also depend on where your boost gauge is getting a reading from, I suppose. My boost gauge is T-ed off of the MAP sensor feed, not the UIM nipple.

POS7 06-08-05 09:35 PM

As promised

PFC 5.08
Com 5.00A

I guess it doesn't really matter on the version.

Its pretty strange that mine shows a 10-8-10 pattern, while yours is showing 6 psi on the pfc and 8.5 psi on the avcr (difference of 2.5 psi).

Perhaps I should tee in a boost guage and test mine as well.


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