[cbatters]

Originally Posted by rdmelton

Ok, this is right out of the manual, correct? (pg 13A-135 and 13A-136)
That means that EGRT Ground is called pin #1; EGRT signal is called pin #2

I know this will sound dumb, but do I connect the EGRT ground to the MAP sensor ground, and the EGRT signal to the MAP sensor signal? The ground to ground sounds right, but it sounds odd that you would send a signal from the MAP sensor to something that already has a voltage output (i.e. pin #2 which is already reading ~4.5V). It seems like that wouldn't work. If I hook it up the other way, then the EGRT signal goes to ground on the MAP sensor, and the MAP sensor signal gets sent to ground, or is that the place where the ECU is looking for the modified EGRT signal?

No such thing as a dumb question when it comes to hooking up wiring correctly. (And thanks again for the heads up on my wiring color error.)

EGRT input has 10K ohm resistor to +4.5V to provide excitation for the EGRT sensor. This is why the logger will show the count at ~229 counts or 90% of full scale before you conect anything to it. (If your connect the EGRT signal to EGRT ground it will go to zero.)

The MAP sensor has sufficiently low output impedance (referred to as sink current) that the 10K pullup on the EGRT input introduces less than 1/4 LSB (near zero) error. (If you were a zealot you could open up the ECU and attempt to find the pullup resistor but it would be a waste of time and you would never see the difference on the logger - and you might screw up your ECU!)

I'll add this info to the FAQ.

Make sure to post when you "Got Boost!" (Boost logging is pretty slick - even better after I added Peak/Hold to MMCd.)


Clint