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?

 

what are the 3 things.

I would wire the pcm to its own, but gauges and such, you may be able to piggyback.

Ryan

 

PCM, Wideband, and boost controller.

 

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.

 

Thanks a ton for that information. I'll get on the horn today and find out.

 

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).