I know there is a blue wire in the distributor which sends out a tach signal but does anyone know which pin on the ECU will this wire end up in? I guess my question is does the blue tach wire from the distributor into any pins on the ECU? I am talking about a 97-98 ITR hence OBD2a...prior to the crank fluctuation sensor days. If the blue wire does not wire up to the ECU directly, how does the ECU/tach register the engine speed?

Thanks.

 

not to be a jerk or anything but why do you need that info? Yes there is a wire that you can wire up a tach at the ecu pinouts. just can't remember which one. I have my tach wired directly at the ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdm wannabe &raquo;</TD></TR><TR><TD CLASS="quote">

all usdm hondas from 96+ have the crank fluctuation sensor
Blue wire sends signal from ignitor to tach
ecu sends signal to distributor through the yellow/green wire</TD></TR></TABLE>

So is this the order of things:

ECU (yellow/green wire, pin A20) --&gt; distributor (blue wire) --&gt; tach

Reason i am asking is because i am getting no signal from the ACC, pin A17, wire from the ECU to trigger my AC compressor. Read somewhere that if the ECU doesn't know that your engine is running (through rpm), it will not turn the AC compressor on hence i want to know how does the ECU determine the engine speed.

 

If I remember correctly the '00 integra Supplement show signal being split right after the ECU harness and it goes to the tach and the ICM(in the distributor), there are a few more places it goes too...but I'd need to go grab the manual and trace the schematic.

Austin

 

The ECU get it's tach signal from the CKP sensor (blue shielded wire) in the distributor. The ECU sends out ignition signals to the ICM (yel/grn), and from the ICM there is a wire going to the tach (blue wire).