Tacho Output Problems

Pin outs, sensor calibrations etc
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Phormula
Posts: 1
Joined: Tue Jun 24, 2008 4:23 pm

Tacho Output Problems

Post by Phormula »

Hi,

I'm having issues with the tacho output from the S8C to my tachometer. The Tachometer used to work directly from a ground on one of the coilpacks. I have since done an engine swap and was hoping to drive it directly from the ECU.

Symptoms: After 4k rpm the needle falls on the gauge back to 0 and then behaves erratically.

Attempted Solutions: I have tried no pullup, 10k and 1k pullups. The 1k pullup improved the output marginally. I have spoken to the gauge manufacturer and they have said that they sometimes require a 1k pullup, but apart from that they do not have problems with their gauges being driven direct from the ECU.

Documentation: http://www.etbinstruments.com/ETB_Gauge ... ometer.pdf

I currently have the pin IO set to an injector output. Should I try an ignition output? Smaller ohm resistor? Unfortunately I can't run from the coilpack as I require 1 pulse per rev.

Any ideas?
Ryan.g
Syvecs Staff - Caretaker
Posts: 498
Joined: Fri May 30, 2008 4:05 pm

Re: Tacho Output Problems

Post by Ryan.g »

Sent you Mail Anthony
pavlo
Zen Performance
Posts: 407
Joined: Mon Aug 04, 2008 10:18 am

Re: Tacho Output Problems

Post by pavlo »

Duty cycle set too high on tacho output.
shmed
Posts: 35
Joined: Fri Jan 10, 2014 11:05 am

Re: Tacho Output Problems

Post by shmed »

On a slight tangent, but I have recently bought a Race Capture Pro to do my data logging, and would like (in the current absence of a CAN module for the RCP) to take (at the very least), a tacho feed from the Syvecs.

I've thought of the following options:

1. Wait for the CAN-bus adapter for the RCP and wire directly into Syvecs
2. Output the CAN info via RS232 from the Syvecs and feed the RS232 input of the RCP
3. Take specific outputs from the Syvecs and send them to the RCP on the input channels

The problem with 1, it requires waiting. Problem with 2, I have bought a BT module for the RCP to allow me to have a dashboard/lap timer up front. This precludes the use of the RS232 input. So, option 3 is where I'm at, and I don't have enough understanding to make it work.

I think what I need to know is, what kind of signal is output from the Syvecs tacho output pin? and Am I ok to 'tap' that feed, or will it affect my speedo/ECU's perception of RPM?
shmed
Posts: 35
Joined: Fri Jan 10, 2014 11:05 am

Re: Tacho Output Problems

Post by shmed »

So, with the lack of response, I decided to tap the wire and send it to the data logger. I now have a dead tacho altogether, though the ECU is aware of the rpm. It's a pink wire on the Mr2 that I tapped. Could I have damaged anything?

My car is also misfiring really badly (not related). Can't see any errors on the ECU though. Is there anything I should look for? It's running COPS through the ECU
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