ECU hangs then knocks

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Re: ECU hangs then knocks

Postby dr20t » Wed Apr 01, 2015 6:23 am

Also if you're ecu was dropping out then you would lose power so that's impossible.

Its definitely a logging drop out not ecu drop out. Mine only did it one day when it was 38 degrees. I put it down to either the cable or something in the hidden hex files but from what Matt is saying it can't be the rom causing drop out so must be the Tactrix itself
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Re: ECU hangs then knocks

Postby cynner » Wed Apr 01, 2015 6:39 am

Could a noisy air pump cause issues? I notice it sounds a bit 'scratchy' when it starts/stops first thing... (although air pump isn't used during normal operation is it - only for first warm up?)
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Re: ECU hangs then knocks

Postby THE SpecB » Wed Apr 01, 2015 7:37 am

cynner wrote:Could a noisy air pump cause issues? I notice it sounds a bit 'scratchy' when it starts/stops first thing... (although air pump isn't used during normal operation is it - only for first warm up?)



Won't be air pump. It's noisy on start up and cycles for approx 60 sec before de activating.

Cold stat ups. As Dr20 said check for noise on cam gears
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Re: ECU hangs then knocks

Postby cynner » Wed Apr 01, 2015 8:18 am

Is that something I can check via logs? The OCV Left/Right seem pretty stable (replaced the OCV's when I got the car).
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Re: ECU hangs then knocks

Postby THE SpecB » Wed Apr 01, 2015 9:26 am

cynner wrote:Is that something I can check via logs? The OCV Left/Right seem pretty stable (replaced the OCV's when I got the car).


Can be checked via logs. If both have been replaced then it won't be that and it would have shown if it is or even one is out with the logging parameters checked.
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Re: ECU hangs then knocks

Postby KiDo_Tuning » Wed Apr 01, 2015 9:25 pm

For verification, this only happens at -3 to +3psi boost, no knock on full noise, no knock under vacuum.

-1.4, -4.2 and -6 degrees pulled in the range to experiment, it ends up pulling more timing the further its pulled(suggesting preignition from not enough timing. Added timing which seemed to solve it but it came back.
Prior to all this, the only time it would knock was after drop out where it would obviously lean out from inj pulse dropping to 0 during drop out, then on resume it would be lean and knock as soon as timing was reapplied.

I added CEL flash on FBK on the last revision, oddly enough it does not register FBKC but it suggests pre-emptive FBKC is active which Cobb Tuning have discussed and said is normal. It is only that a local workshop said they had knock on knock ears that concerns me. PFBKC is timing retard during rapid airflow change to prevent knock. More timing being pulled would obviously affect airflow as it generates more load due to lack of timing causing incomplete combustion(load increases as RPM slows)
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Re: ECU hangs then knocks

Postby <GB> » Thu Apr 02, 2015 12:05 pm

i think my car suffers pre emtive knock
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Re: ECU hangs then knocks

Postby alexeiwoody » Thu Apr 16, 2015 12:57 am

Any updates, Kim?
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Re: ECU hangs then knocks

Postby Robbks » Thu Apr 16, 2015 9:25 am

Kim's on Holidays in South America..

KiDo_Tuning wrote:It is only that a local workshop said they had knock on knock ears that concerns me.

Matt,

What's the chances of the "noise" which sounds like knock through knock ears being valve-train noise from the cam gears whipping around.
i.e what are the cams doing at those points in time.?

I suggested to Kim to have you flatten the AVCS maps as a test, or at least slow their opening if they are doing it at those points..?
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Re: ECU hangs then knocks

Postby KiDo_Tuning » Thu Apr 16, 2015 5:34 pm

Robbks wrote:Kim's on Holidays in South America..

KiDo_Tuning wrote:It is only that a local workshop said they had knock on knock ears that concerns me.

Matt,

What's the chances of the "noise" which sounds like knock through knock ears being valve-train noise from the cam gears whipping around.
i.e what are the cams doing at those points in time.?

I suggested to Kim to have you flatten the AVCS maps as a test, or at least slow their opening if they are doing it at those points..?


I am posting my knock ears to USS so I can use them while I am down myself. It is my suspicion too. Considering CEL flash has no pickup on FBKC, so its either pre-emptive or the ECU hang is causing it and it wont flash due to hang proving the processor is tied up.

Seen it in a few cars from various tuners after looking through logs so its not exclusive to tune, its obviously something but actually WHAT causes it is the issue. The LGT got stuck with a CANBUS version of the 06 32bit non-CAN ECU. It was a total hybrid that even Denso themselves have said was not the prettiest design.

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Re: ECU hangs then knocks

Postby west_minist » Fri Apr 17, 2015 4:45 am

Quickly reading a few threads, this what I notices with such ecu issues:

If there is a ignition pick up issues, you will have this issues. Its the only time the ecu spends most of its cpu cycles. After all, all operations are based on the ecu knowing where the engine is.

Logging is secondary and will be put on pauses.

You will need to check from the ecu to the sensors. Cam & Crank sensors. ANy noise due to wiring issues to connection issues to sensor issues will result in such behaviour. Remember knowing where the engine timing is...Is key to the ECU :)

If you can simulate the issue, which can be sometimes g's forces on the car, scope the both sensors at the ecu if you want to have some fun, but it can be frustration.

Oh Logging will not tell you this. You need to atleast have a very high sample rate to do so for which general ecu loggging will not show.

I hope the following helps.

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Re: ECU hangs then knocks

Postby cynner » Tue May 05, 2015 4:28 pm

Just an update...

I think the "ECU hang" is simply because I was logging too many values.

I think my knock issue may be due to some false knock somewhere... the ECU then pulls timing when it doesn't need to, and running not enough timing results in detonation (so in effect, false knock causes real knock).

I'm not really sure where to go from here... wastegate chatter has been ruled out (WG set to zero in the tune for testing). I suspect maybe this has started happening since driving the car on a very bumpy road... maybe something has rattled loose. I've had the exhaust checked out - no leaks or rattles.

I think I've spent well over $1000 on mechanics chasing this issue :(
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Re: ECU hangs then knocks

Postby my9999 » Sat Dec 17, 2016 11:24 pm

cynner wrote:Just an update...

I think the "ECU hang" is simply because I was logging too many values.

I think my knock issue may be due to some false knock somewhere... the ECU then pulls timing when it doesn't need to, and running not enough timing results in detonation (so in effect, false knock causes real knock).

I'm not really sure where to go from here... wastegate chatter has been ruled out (WG set to zero in the tune for testing). I suspect maybe this has started happening since driving the car on a very bumpy road... maybe something has rattled loose. I've had the exhaust checked out - no leaks or rattles.

I think I've spent well over $1000 on mechanics chasing this issue :(


Long time ago i know. But did you figure it out?
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Re: ECU hangs then knocks

Postby cynner » Sun Dec 18, 2016 8:17 am

Nup still not figured out. New engine later and it still does it.
Pretty sure it may be gearbox our clutch - as replacing the pitch so that goes between the gearbox and engine block (near where the knock sensor is) made a big difference (softer bushes means less knock).
For now I've fitted a knock link light and changed the tune to ignore knock below 1.25 load. Not ideal, but just waiting till I need a new clutch :)
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Re: ECU hangs then knocks

Postby jaydece » Mon Dec 19, 2016 3:52 pm

Very sad to read this thread and see that after all this time your still having issues with the car.......Feels like forever...

Heres to you in 2017 - being a lot less knock of a year.....
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