Corsa poor starting and cutting out

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Re: Corsa poor starting and cutting out

Postby Bopbop » Wed Aug 31, 2016 7:45 am

steevegt wrote:
STC wrote:As for Very Deep Digging - How do you Dig any Deeper unless you start to decode CAN Messages or throw bits at it ?


That was my definition for very deep digging. But I guess that is impractical... Or isn't it?
Never saw anyone doing diagnose work based on can bus frame data... Except checking for valid CRC I guess.
Maybe in the future, diagnostic work are going/need to be doing more stuff based on the frames data itself... Who knows...
Without documentation from the manufacture, that is going to be hard...


There is software and hardware available to do this.
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Re: Corsa poor starting and cutting out

Postby STC » Wed Aug 31, 2016 7:57 am

There is software and hardware available to do this.

The Pico does it, gets it to Hex.

Translating it into English will be tricky time consuming bit. I have watched the KTS developers do it and it is all Smoke & Mirrors at first.
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Re: Corsa poor starting and cutting out

Postby STC » Wed Aug 31, 2016 9:32 pm

That was my definition for very deep digging. But I guess that is impractical... Or isn't it?


It is scary, but that may be what we have to study and master next.

At the moment we are handcuffed into accepting CAN messages if they are at the right voltages and Kbits/s and look good with an equally good mirror image? Like a speed dating, singles night at the local pub :D

When and if we get there, we will see the inaccuracies of scantool fault codes and data. And wont rely on them as we have to now
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Re: Corsa poor starting and cutting out

Postby Bopbop » Thu Sep 01, 2016 1:35 pm

STC wrote:Ian

You have provided very little information to work with

it starts out ok then goes into a wobbly

What does that mean ???

Last time I saw B1485 (Exciter current generator terminal 61) on a similar Corsa it was charging ok. The only symptom was the battery light illuminated on the dash. TIS Guided fault finding IIRC looks for confirmation that the alternator is good and the wire from alternator to BCM is intact and then tells you either the BCM or ECU is faulty. In my case a new BCM didn't fix it so I took it off put an ECU (Engine) on and it fixed.

Your scope waveform is good, which we can take for granted if we have global communication & no fault codes for bad CAN, Missing Messages etc.

Someone here maybe able to help you further if you were to post the results of a global scan and describe the fault with the car with some detail and relevant measured values.




Hi STC you say my waveform is good but what is happening on screen number 17 and 21 also on 24 there seems an anomaly it seems the CAN has a problem somewhere
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Re: Corsa poor starting and cutting out

Postby volrem » Thu Sep 01, 2016 2:59 pm

You have too small timebase for CAN capture. Use longer timebase to capture more data (increase sample rate also) and use ZOOM function. Zoom is one of the biggest power in Pico.

But i would say that it's just noise or grounding issue. And when applying math channel we can see that control module sees it fine.

You can't judge CAN from 500 microsecond capture. Need to see bigger picture. Not even enough time to decode since whole message won't fit in that timebase.
Attachments
math.png
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Re: Corsa poor starting and cutting out

Postby Dcunning35 » Thu Sep 01, 2016 6:20 pm

The car came in as a non start ,now runs though rough and you have a coms or battery threshold dtc for the generator.
I would work on why the car runs rough and you mentioned spark angle was erratic could this not be ckp related? Try checking ckp and cmp correlate I'm not that familiar with vauxhall but if engine is erratic so would alternator speed ,could this dtc be logged due to a commanded charge rate not being achieved.
Or am I throwing darts lol.
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Re: Corsa poor starting and cutting out

Postby STC » Thu Sep 01, 2016 8:06 pm

Ian

If the Exciter wire fault is niggling you and you cant get past it you have 2 options:
1. Fix it first ! or
2. Fully Charged Battery. Take all the wiring off the alternator, tape up the connectors for safety and attach a Battery support unit to the car set at around 14v, or jump leads to a nearby car with a known good charging system with its engine running.

As confirmed by Volrem your Can is good. It is a very robust, reliable data exchange medium. Generally speaking (just my experience) it takes prolonged water damage and subsequent corrosion, Collision damage to wiring or Wrong Technique Jump Starting to knock it out.

I have previously asked,

Vacuum Gauge on Manifold ?
Measured Values ?? - Opcom will allow you to save to file, which you can post at idle and 2000rpm if that can be sustained ??

If your looking for that Golden Nugget or a Silver Bullet, Which Sensor should I replace to fix it then I cannot help, not because I don't want to, because I cannot.

I will, forevermore throw test plans at you and expect accurate answer. Where in the World are you ?? It is fixable !!! All we have to do is return it to the sort of state it left the factory in. Not a big ask?

When running it will start to run poorly misfiring and popping

Popping in the Intake tract ??

i have noticed is the "spark timing" seems to wander erratically all of the time.


Cause or Consequence ? It may be desperately trying to keep itself alive. Ever seen a headless chicken ?
All compressions are good


I assume Compressions were measured at cranking speed (~150 to ~200 rpm) ?? If so, a complete waste of time if your fault occurs at 800 rpm and above.

You have a 4 Channel scope, your best friend right now.

With it running
Channel A - Crank Position Sensor
Channel B - Injector 1 Command
Channel C - Amp Clamp on Coil Pack Earth or Power Wire
Channel D - Amp Clamp (2) on common wire to all 4 Injectors.

Enough time on the screen to see between 4 & 6 Revolutions of the Crank, Injector 1 firing 2- 3 times.

Then from Ignition off, Ignition on, crank, start, idle, WOT and back to idle.
Channel C for - O2S1 Voltage ( 4 or 6 wire) ?
Channel D for - MAF Voltage

Finally (For now) Start to idle then SNAP WOT
Ch 1 APP feedback 1 or 2
Ch 2 MAF
Ch 3. O2S1
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