ecu issues

GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

stevieturbo wrote:Your engine does still run, albeit badly when you have lost comms with the ecu, for several seconds after comms is lost

So the ecu must still be alive in order for the engine to be running. IMO that does point to a communications issue, at least in that respect whether cable or otherwise.

If the ecu did shutoff, the engine would die instantly. That is not happening.

A Datalog of the entire video would be helpful including some time after shutdown, or as long as you can, including things like limpmode and engine enable etc.

Device at the top is illuminated. What errors are present ?
For example, if the motor has 2000 rpm and only 2 sec the voltage to the control unit is missing. then he is not completely out ... that's like when I turn off the ignition key only briefly and again
GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

TimH wrote:OK, watched with no sound on, sorry.

What car?
Its a audi tt 8j 2.0 tfsi
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: ecu issues

Post by stevieturbo »

GLDN6 wrote:
stevieturbo wrote:Your engine does still run, albeit badly when you have lost comms with the ecu, for several seconds after comms is lost

So the ecu must still be alive in order for the engine to be running. IMO that does point to a communications issue, at least in that respect whether cable or otherwise.

If the ecu did shutoff, the engine would die instantly. That is not happening.

A Datalog of the entire video would be helpful including some time after shutdown, or as long as you can, including things like limpmode and engine enable etc.

Device at the top is illuminated. What errors are present ?
For example, if the motor has 2000 rpm and only 2 sec the voltage to the control unit is missing. then he is not completely out ... that's like when I turn off the ignition key only briefly and again
Your engine is not dead. Rpm is rising and falling as such the ecu should be alive. What you have shown thus far indicates that the ecu is still alive, but perhaps fuel pump relay or something is not.

Again....check voltage supply to the ecu and post a datalog of the incident happening. Set the ecu to log continuously with engine off so it will record the timeline regardless, then it will be easy to see if it is shutting off after engine stop, or still logging.
GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

here are the logs of the video are about every second second switches off

https://imgur.com/a/JPNiHCz
GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

stevieturbo wrote:
GLDN6 wrote:
stevieturbo wrote:Your engine does still run, albeit badly when you have lost comms with the ecu, for several seconds after comms is lost

So the ecu must still be alive in order for the engine to be running. IMO that does point to a communications issue, at least in that respect whether cable or otherwise.

If the ecu did shutoff, the engine would die instantly. That is not happening.

A Datalog of the entire video would be helpful including some time after shutdown, or as long as you can, including things like limpmode and engine enable etc.

Device at the top is illuminated. What errors are present ?
For example, if the motor has 2000 rpm and only 2 sec the voltage to the control unit is missing. then he is not completely out ... that's like when I turn off the ignition key only briefly and again
Your engine is not dead. Rpm is rising and falling as such the ecu should be alive. What you have shown thus far indicates that the ecu is still alive, but perhaps fuel pump relay or something is not.

Again....check voltage supply to the ecu and post a datalog of the incident happening. Set the ecu to log continuously with engine off so it will record the timeline regardless, then it will be easy to see if it is shutting off after engine stop, or still logging.

do you have an attitude for me as I set the data logging so that always logs with?
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: ecu issues

Post by stevieturbo »

Attitude ?

Your screenshots shows you have downloaded multiple log files.

Ideally for this you want one long file.

ie, set logging to start at 0rpm, 0 throttle, 0 speed etc, so if the ecu is powered up, it is logging regardless of engine running ( with similar logging off parameters )

If need be open up a gauge for logging active so you can see if your settings have activated logging ok with engine off.
GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

stevieturbo wrote:Attitude ?

Your screenshots shows you have downloaded multiple log files.

Ideally for this you want one long file.

ie, set logging to start at 0rpm, 0 throttle, 0 speed etc, so if the ecu is powered up, it is logging regardless of engine running ( with similar logging off parameters )

If need be open up a gauge for logging active so you can see if your settings have activated logging ok with engine off.
I did it the way you wanted. but I have so many logs again. So the control unit turns off.

I checked all relays and they are ok.

Slowly I think that the syvecs has a cold solder joint or other.

https://imgur.com/a/NxMnyuE
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: ecu issues

Post by stevieturbo »

If you did it the way I wanted, there would be one single log file for the duration the ecu is powered up. Not multiple short log files.

And of course the content of those logs would be a little more important than posting a screenshot of how many logs there are.

Set the logging as I describe, so it logs continuously when the ecu is powered up. Sit with key on for say 30 seconds prior to starting, start engine then do what you need to do until the problem occurs.

Again, do not turn the key off for say another 30 seconds so if the ecu is still alive we can see this with the log.

Then key off, power down, save the log and upload it so we can view it. Again ensuring things like engine enable, limp mode, etc are logged.

Also, if the ecu is also trigger any power hold relays or anything, those outputs status should be logged too, although not sure if the S8 does that sort of thing anyway.

Of course the other option is for you to also manually test for 12v to the ecu etc during this problem.
GLDN6
Posts: 42
Joined: Tue Sep 05, 2017 7:35 pm

Re: ecu issues

Post by GLDN6 »

the video is based on the logs I made

https://streamable.com/w3z9s
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: ecu issues

Post by stevieturbo »

your videos show little of any use.

They show only small pieces of information. You have a voltmeter attached...but you do not state what it is connected to, nor do you correlate the voltmeter reading with what is happening at the engine or the laptop etc.

In that last video, comms with the ecu seems to stop, but the engine is still running quiet well...then comms is regained. That does not sound like the ecu is shutting down

But a datalog with the exact time sequence I described, would help see if that is happening
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