map sensor faulty reading??
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Cheese
Joined: May 2001
Posts: 452
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From: Australia
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?
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?
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Joined: Dec 2001
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From: San Lorenzo, California
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.
Wankel Shmankel
Joined: Mar 2005
Posts: 627
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From: Oahu (Hawaii)
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.
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.
Last edited by POS7; Jun 8, 2005 at 05:35 PM.
Lives on the Forum
Joined: Dec 2001
Posts: 14,716
Likes: 10
From: San Lorenzo, California
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.
Wankel Shmankel
Joined: Mar 2005
Posts: 627
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From: Oahu (Hawaii)
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.
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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