HELP: Need Tach Signal!!
 

Does anyone know where I can get a tach signal inside the car? I would rather not grab a signal off the engine. There has to be a signal at the Body ECU, but my o-scope is broke so I can't find it.

Any help is appreciated!!

There isn't one.

Sorry.

Jeff

I don't believe that. There has to be a tach signal for the OEM tachometer in the gauge cluster. Unless it's in a data stream from the engine bay...

Here you go: http://www.ft86club.com/forums/showthread.php?t=10292


Should be able to follow that to its termination, however it very well may terminate in the engine bay into a control module, and not go all the way to the ECU in the cabin.

Hmm. Thanks, but still not helping. I'm hoping someone knows what pin on the Body ECU under the dash is the tach signal. I hate splicing into wires in the engine bay.

The tach signal is communicated between the Engine ECU and Gauge Cluster, etc. on the CAN BUS. There is no single wire for tach, it is a data stream.

I didn't just guess before I posted, I looked it up first.

Jeff

:cry:

Ok, thanks. I guess I'll do some solder/heat shrink under the hood...

Why do you not want to grab the tach signal in the engine bay? With a little spray silicone you should be able to run the wire through an existing hole in a grommet.

I actually already have wires run into the engine bay for the tach wire as well as for my amp. I just dislike tapping into a wire under the hood with the Michigan/Ohio winters. But since that's the only source, then I'll have to run with it.

The schematic I'm using shows 4 tach signals on the passenger side large connector. So I'm going to try those.

If theres a red/black at the obd 2 connector you can get tach there.

Oh yeah, I forgot winter even existed. :lol: We have a few months out of the year that require a hoody and jeans but that's it.

Looking into it further, it looks like the ECU has a dedicated "TACH" output signal, pin A35-15 on the ECU. This is the 35-pin connector.

It probably heads over to the DLC2 connector or something, because it isn't heading to any other systems in any of the wiring diagrams which is where I initially checked. Every other ECU, etc. uses the CAN-BUS to get the tach signal, but as I said there is an output dedicated to it on the ECU. It's not shown in any wiring diagrams, but it is mentioned in the RM.

Nice of them to do that.

Jeff

subscribed.

subd as well... if jeff lange is on top of this research it will be no time at all till a definitive answer. Guy knows his shit.