View Full Version : Help required

March 11th, 2008, 09:45 PM
Hi i am running efi-live V4 pro (licensed :-) )in my HJ monaro.
It is running the 165 ECM and the $12 VR def and 5.0lt engine
Also using a USB datalogging cable and Ostrich 2.0.(not at the same time)
Everything works fine.
I can connect efi-live with no problems and all displays work.
I select "engine data" in macros and turn ignition to "on" and data flows as normal.I select "charts" and "toggle logging on/off" and data flows and shows traces on chart display.
When i start vehicle data trace is still flowing until about 15 secs into logging and then i get " com time-out" or "Can't write to Com4. A device attached to the system is not functioning"
It seems to always happen when vehicle runs after a few secs.
Would having the "checksum disabled" through Ostrich 2.0 effect this or is it a timing issue?
I've tried the Eval version thinking it's just the amount of logging time eg 30 sec limit.
Now have the pro license (which i wanted anyway)and still the same issue....so much time trying ways to datalog in the last 2 months it's driving me nuts:bash: :bash:
I know its a problem on my side,not EFI-live......HELP!!!!
Thanks for any advice.....Mario

March 11th, 2008, 11:57 PM
Ok i was able to d/log and save 15 secs and noticed on playback it's running @ 1 frame per sec compared to efi's gmh-vs8 dyno.alg @ 5 frames per second.
I'll post any other symptoms i find.

March 12th, 2008, 07:27 AM
Turn on the menu option View->Serial IO. That will display more detailed information about the comms between the vehicle and the PC. Then start data logging. Once it fails (or you may need to stop it manually after about 10-15 seconds if it does not fail), right click on the text display and select "Copy all". Paste it into an email and send it to me at paul@efilive.com. Please put a reference to this post in the email so I can correlate it to this post. Regards Paul

March 13th, 2008, 12:20 AM
Thanks Paul, i will give it a try and email you the results tomorrow night and thanks for your help.

May 6th, 2008, 09:46 PM
Hi Paul,i haven't been able to get back to you regarding my previous issues but all is ok now as it turned out to be a dodgy interface.
I have a quick question though....the read out for O2 mv,should the needle swing violently anywhere from 100mv -900mv or should it stay stable @ the sensed mixture?
Mine seems pretty stable @ around 450-500mv when it reaches closed loop and AFR goes to 14.7 then once i've driven about 1-2 kms the needle swings back and forth violently but the AFR stays @14.7 until it reaches open loop again and stabilises
Could it be a dodgy o2 sensor?
Thanks for all your help.

May 6th, 2008, 10:02 PM
That is exactly what it should do when working correctly.

While it is warming up or while the PCM is commanding anything other than 14.7 the O2 sensor will read rich (high) or lean (low).

Once the PCM is operating in closed loop, the O2 sensor will swing up and down between about 100mV and 900mV. I've copied some of the explanation of closed loop from our V7 user manual...

With the information from the sensors, the PCM knows the conditions in the engine, how much air is flowing and therefore, the desired load to be placed on the engine. But how does the PCM know the amount of fuel to inject? This is the main function of the oxygen sensors. The oxygen sensors generate a small electric current, with voltage varying from around 0.1 to 0.95 volts. Less voltage indicates a lean condition and more voltage indicates a rich condition. They measure the difference between the amount of oxygen in the exhaust and the amount of oxygen in the atmosphere.
Since the PCM knows the amount of air and fuel entering the engine and, from the oxygen sensors, the amount of oxygen remaining after combustion, it can determine if the combustion process was rich or lean. This is a direct feedback system and enables the PCM to "Close the Loop"!
Because the feedback from the oxygen sensors can only be applied “after the fact”, it causes the PCM to “chase its tail” to achieve the correct combustion. This chase can be observed clearly in the oxygen sensors’ output, which under everyday driving conditions looks like a wave.
The combustion process is constantly oscillating between rich and lean. As long as this process continues to change from rich to lean in a timely manner, the PCM “knows” that the combustion is within acceptable limits. If the oxygen sensor voltage stays high or low for too long, then the PCM adjusts the amount of fuel delivered by the injectors. This adjustment is called the Short Term Fuel Trim (STFT) correction.

May 6th, 2008, 10:05 PM
For tuning purposes (not that EFILive can tune OBDI vehicles), you need to use a wide band O2 sensor and controller. The wide band O2 sensor provides a steady "sensed" voltage like you were expecting to see.

The "narrow band" O2 sensors are fitted to vehicles only because they are cheaper than wide band sensors. When wide band sensors are eventually standard in all vehicles (and I think they will be one day), you will see the exact sensed AFR instead of the oscillations you see now.


May 6th, 2008, 11:14 PM
Thanks again Paul,i wasn't 100% sure as i also D/L my C/dore VT6 and the O2 read outs were more stable.
I am using an Autronic W/B further downstream and yes the readouts are much more stable.
Haven't decided if i prefer the A/F setting or using the lambda setting...lol