I am preparing to install a head-up display, and I need to find signals for vehicle speed and engine RPM. I don't have the Serice Manual, only the Electrical Troubleshooting book, which turned out less informative than I hoped for. I think I found the speed output on wire A11 from the ECM, but I have problems with tach signal. It should come from a sensor, named Camshaft Position, or Crankshaft Position or something similar, but I don't see anything like that on the schematics. I did find few sensors, where I can't identify purpose, and I suspect that one of them is what I need. All I know that they are located on the engine and connect to the ECM. They are called CMP Sensor and CKP Sensor. Anyone with a Service Manual, please look up what those sensors do. Thanks a lot!

 

CMP is the camshaft position sensor, and CKP is the crankshaft position sensor.

Since the TL already has a tachometer, can you get the signal from the existing tach? I don't know how to do this, just an idea for you.

The tach is connected to the Power supply circuit/controller area network controller, in case that is in your electrical manual. I couldn't find too much more about this in the service manual.

 

Ron, thanks! Probably any of the sensors will work for a tach signal. Unfortunately it looks like I will not be able to use any of them. I took the car apart already, and I can't even see the ECM, it is located very deep behind HVAC ducts. The speed sensor wire is connected to the naviunit and is relatively easy to access.
Tach signal is not present at the instrument cluster. It is transmitted in an encoded form over the network bus and decoding it is next to impossible.
I am also installing Comptech Short Shifter, so I had to take apart a lot. Ugly and bloody work

 

I dont have the fsm either, but when i saw his post, that's exactly what i thought...

CaMshaft Position
CranKshaft Position

 

Turned out that access to the ECU was easy- once I figured that it has to be done from the right side, not center. Actually, it doesn't require any disassembly- only removal of a retainer and puling the carpet do the trick. Speed sensor connection worked immediately, but tach is still a problem. None of the sensors provide a signal, which can be read by the HUD device. CMP seems to output a right frequency, but display readings are unreliable, which tells me that amplitude or shape of the signal is wrong. CKP sensor pulses to frequently, the tach reads 4 times of what it should.
First impressions from the HUD are very positive. Seeing your speed on the windshield beats looking down at the dashboard cluster. I will post pictures when I permanently attach the display- I am still searching the optimal location.

 

dumb question, but is honda still using a blue wire for the tach signal?

 

There is no wire for a tach signal, so I am trying to find an alternate hook up location

 

let me know if this helps you

or if you need more info

 

GT1, Are you taking pics as you go for the HUD install? Maybe you could do a quick write-up after it's done and share some pics of the install/final product.

 

rbf351,
Thanks, this is matches the digram I have in the manual. I tried all 3 sensor outputs, all of them don't work, but in a different way I am going to check the signals with an oscilloscope to better understand my options. Do you have an access to troubleshooting procedures for the sensors? They might have information on voltage and shape of signals they output.
Scribesoft,
I took few pictures, but I realized that they will not do much good to someone who is installing only HUD. I started with installation of a Short Throw Shifter, which required much more disassembly. If I was installing HUD alone, I would probably find different points to hook up power wires.

 

bump - any progress - thinking about doing this too!

 

Well, I have the head up display for more than a year now, and I am very pleased with it. Speedo is working flawlessly, but I couldn't get the tach to work. I went as far as hooking up an oscilloscope to the car. Looks like that the tach sensor outputs a series of pulses for each turn. I tried signal shaper and frequency divider, but had no luck. I decided to stop at that point because I didn't want my car to idle for hours at various engine speeds while I am doing my research and troubleshooting. Having a working tach display would be great, but I love my HUD even the way it is.

 

Which wire did you tap the SPEEDO into and have a pic of the HUD and where you mounted it?

 

I just moved and my home internet is till down. I will get the info in few days.

 

Speed sensor output is on a blue wire going to ECU connector D, pin 14. ECU is fairly easy to access from a passenger side foot well.

 

more info on this please, post some more pictures too.
thank.

 

Sorry, made a mistake. Speed signal on ECU connector A pin 11. This is a blue/ white wire.
THTL, please ask specific questions- I have no idea waht exactly you need to know.

 

i gotta bump this thread up. you have a picture of where i can find the ECU ..

 

it sounds like you might need a tach driver from msd. it basically taps into the signal from the ckp and creates a proper tach signal for atermarket products like tachometers and engine managment sytems.