Using one 3bar map for three signals?
07-06-2009, 11:03 AM
#1
FormerVendor
Thread Starter
iTrader: (7)
Join Date: Dec 2004
Posts: 373
Likes: 0
Received 0 Likes
on
0 Posts
Using one 3bar map for three signals? I have three things that need a signal from a 3bar. Please tell me I don't have to run three separate sensors? Can I just power and ground it from one thing and use the signal wire back to all three of them?
07-07-2009, 10:58 AM
#4
LS1TECH Sponsor
iTrader: (6)
Join Date: Jun 2007
Location: Boca Raton, FL
Posts: 174
Likes: 0
Received 0 Likes
on
0 Posts
With any electronic sensor, it depends on what it is that you're hooking it up to. Not by function, but by current draw. If the three items have extremely high impedence (high resistance values), then you should be able to run all three without issue. With mid- or lower impedence levels, all three components tied together may cause a low enough total circuit impedence leading to signal drop and false sensor readings. Before hooking anything up, consult the manufacturers of the WO2 and boost controller to determine if total impedence will be too low (less than 3 MegaOhms total is too low). If you've determined that it should be safe according to specification, double-check by first hooking up the ECM and checking the data reading for manifold pressure. Then hook up the WO2 and boost controller (making sure the O2 is up to temp) and check to see if the manifold pressure value has changed. If it has, buy another MAP. If it's still the same, you're ready to rock.
07-08-2009, 12:54 PM
#5
FormerVendor
Thread Starter
iTrader: (7)
Join Date: Dec 2004
Posts: 373
Likes: 0
Received 0 Likes
on
0 Posts
With any electronic sensor, it depends on what it is that you're hooking it up to. Not by function, but by current draw. If the three items have extremely high impedence (high resistance values), then you should be able to run all three without issue. With mid- or lower impedence levels, all three components tied together may cause a low enough total circuit impedence leading to signal drop and false sensor readings. Before hooking anything up, consult the manufacturers of the WO2 and boost controller to determine if total impedence will be too low (less than 3 MegaOhms total is too low). If you've determined that it should be safe according to specification, double-check by first hooking up the ECM and checking the data reading for manifold pressure. Then hook up the WO2 and boost controller (making sure the O2 is up to temp) and check to see if the manifold pressure value has changed. If it has, buy another MAP. If it's still the same, you're ready to rock.
07-08-2009, 01:20 PM
#6
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
As a "gut check", look at the key on, engine off
MAP sensor voltage through the scan tool with
only the PCM connected, then attach the other
two things. Same reading = OK, degraded output
= not-OK (so maybe add a buffer amplifier, or a
secondary MAP sensor for the add-ons).
MAP sensor voltage through the scan tool with
only the PCM connected, then attach the other
two things. Same reading = OK, degraded output
= not-OK (so maybe add a buffer amplifier, or a
secondary MAP sensor for the add-ons).