[CinciBlueBimmer]

I'm installing a data logger and need to access the tachometer signal. Does anyone know which wire is the tach signal? Under the dash is the best access point for me.

Thanks!

[///Matt]

There is no "tachometer" signal. It's all bussed information on a single signal wire. You're not able to access the tach info!

[tintivilus]

Originally Posted by ///Matt

You're not able to access the tach info!

That sounds like a challenge

Isn't it just on a CANbus? I'm sure someone sufficiently motivated could figure it out.

[Placey]

If you could decipher the bussing signal off the PT-CAN going to the DME, and have something convert that to a signal that can be read to go into the Data logger, then maybe it'll work.

but odds are, you're probably out of luck.....

[shyestsparks]

Originally Posted by Placey

If you could decipher the bussing signal off the PT-CAN going to the DME, and have something convert that to a signal that can be read to go into the Data logger, then maybe it'll work.

but odds are, you're probably out of luck.....

Or you could just use the crank angle and cam angle signals just like how the 350Z guys do it (VQ35 has a CAN system also).

[Placey]

I dont think its a hall-effect signal coming off the crank (on-off). therefore i dont know if anything aftermarket would be able to read the signal.
Matt, can you back me up on this, or did they put a standard crank sensor in the E90?

[Chesmu]

You could take the half-crank cam signal off the DME BUS signal and tap that into the dual-damper tacho-signal. Then just cross-wire the cam signal with the hall-effect crank (on-off).

Pretty straight forward.

BTW: The e90 doesn't have a crank, much less a crank sensor....DUH!

[///Matt]

Chesmu, your post makes my eyes hurt. WTF are you talking about?



Placey, I'm pretty sure the crank sensor on the E90 is just your standard hall, with the 60-2 crank teeth... I'd have to check. My E90 book is at work, and I won't be into work all week, though I am in Ontario all week for St-055.

Matt

[Chesmu]

Originally Posted by ///Matt

WTF are you talking about?

Exactly my point.

[CinciBlueBimmer]

Thanks guys... I think...

A couple of thoughts:

1. Is there a tach signal coming into (or out of) the DME? Seems like one of those pins would be RPM

2. Could I get an inductive signal - or even a direct tap - off of a fuel injector power line?

Somewhere... somewhere there must be a "real" tach signal that goes into the computer to be CAN-bus-ized. I just have no clue where to find it.

Thanks!

[CinciBlueBimmer]

I decided to scope my OBD-II connector with the hope that I'd stumble onto the RPM output, and sure enough, I hit a square wave on Pin #10!

I ran it to my data logger and bingo, a perfect readout.

Here's a picture of the pin location, FYI:

[FrankoQ]

Originally Posted by Cinci330i

I decided to scope my OBD-II connector with the hope that I'd stumble onto the RPM output, and sure enough, I hit a square wave on Pin #10!

I ran it to my data logger and bingo, a perfect readout.

Here's a picture of the pin location, FYI:

Mmmm
More pics and more details please.

[CinciBlueBimmer]

I'm going on vacation for the next week but when I get back I'll do the install of my G2Extreme data logger and post pix.