astra z16xep throttle body fault

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Re: astra z16xep throttle body fault

Postby Robski » Tue Aug 21, 2012 3:49 pm

Why does the TP sensor 1 voltage jump from 0.9X V to 0.3X V & do nothing else ?

Also the clip with the scope image,the red trace CHB doesn't look to be being grounded to me & is too far zoomed in to be able to see really in that clip whats going on.

TBH i find posting youtube clips a poor way of trying to see/hear what is going on, i would rather see the PSD file or at least a screenshot of a trouble area.

You keep saying the PCM is commanding the TB shut, how do you know this ? i see no current captures or any for that matter of what you claim to have scoped apart from this youtube clip.

Have you not considered that either teeth have jumped/stripped in the TB & the PCM is actually trying to drive it the correct way ?

I did ask how far the TB plate is opening KOEO @ WOT but got no sense back on another forum :?:
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Re: astra z16xep throttle body fault

Postby djautos » Tue Aug 21, 2012 8:00 pm

checked teeth all good.
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Re: astra z16xep throttle body fault

Postby djautos » Tue Aug 21, 2012 8:11 pm

scoped tps and both trace's are good. the voltages are just representing what the throttle body is doing. can i as why you would use amp clamp.
thanks for replys
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Re: astra z16xep throttle body fault

Postby Robski » Tue Aug 21, 2012 9:03 pm

scoped tps and both trace's are good


APP sensor :?: or TPS :?: And again only your word they are 'good' :!:

can i as why you would use amp clamp


Why would you think :?:

When i look at anything with a motor i look at both voltage & current.
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Re: astra z16xep throttle body fault

Postby Avdr » Wed Aug 22, 2012 7:07 am

I'm not a wizz with the car you've got in, but have you tried connecting the TB plug using only one pair of postion wires?

ie. There will be two tracks within TB, Can you leave one connected to ECU and not connect the other, but still connect your motor feeds?
Just an idea really...
Also I've got a TB from a z14xep here, part number is different to that a z16 though, but if you want any data from it, resistance values etc (cant guarentee the validity). Give me a shout on here, or email enquiries(at)avdr.co.uk

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Re: astra z16xep throttle body fault

Postby Liteace » Wed Aug 22, 2012 8:37 am

The last video, this one:

https://www.youtube.com/watch?v=yHthW_OA124

Is that banging noise the TB snapping shut or someone else in the workshop hammering something ?
DONT SHOOT YOURSELF IN THE FOOT
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Re: astra z16xep throttle body fault

Postby Paul88 » Wed Aug 22, 2012 6:35 pm

Liteace the background noise is the throttle banging shut.

The ecu is commanding the throttle to close, when it should be commanding it to open. In response to the pedal being pressed.

The two wires that run to the motor from the ecu can be seen on the scope screen as blue and red. If you command the throttle open with the Vauxcom then the red trace switches to ground and the throttle opens.

The throttle plate as three position.... open.... idle.... and fully closed.

The blue trace is the command for the throttle to close beyond the idle position.....

Its default position seems to be idle (slightly open) with the throttle body unplugged it will start and idle. With it plugged in it goes to the fully closed position and will not start. No air can by-pass the throttle plate and there is no idle air by-pass set up on this system.

The question we need to answer is... in normal operation what is the fully closed position used for ? Is just to shut the air flow down when the engine is switched off. Or is there another reason for it.....

Thanks in advance Paul88.............
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Re: astra z16xep throttle body fault

Postby antthecat » Wed Aug 22, 2012 6:46 pm

I'm guessing why the throttle closes off to aid engine braking at decelleration. Also I'm presuming it needs to know where fully closed position so it can adapt a good idle position if the plate gets gummed up.

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Re: astra z16xep throttle body fault

Postby Robski » Wed Aug 22, 2012 6:58 pm

I would say for clean shut down with no shudder.
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Re: astra z16xep throttle body fault

Postby Paul88 » Wed Aug 22, 2012 7:25 pm

Thanks Ant and Robski for the response... Good answers (They make good sense)

So if we follow the theory through... I now need to know why is the ecu commanding the throttle to close ?

Is it responding to inputs from the vehicle i.e accelerator pedal or is it a faulty ecu.

The pedal potentiometer as been checked at the ecu (Picoscope) and is good.

Would the ecu look at any other inputs for the throttle close command ?

Thanks again in advance Paul88...
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