Opel Corsa D Z12XEP no start

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liviu2004
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Opel Corsa D Z12XEP no start

Post by liviu2004 »

This is a fast one. Crank, no start, fuel pressure ok, bi-directional control can spark the plugs, no fault codes.

During crank, rpm on diag erratic. You all know where this goes. Crankshaft sensor. But funny how it fails.
crank corsa d.png
Do you see anything wrong? Well, thanks to youtube, I learned that the extra dip at the missing teeths is no good. ECU counts that as well and cannot sort out the crank position. If I would only had a capacitor decade box ....

One week later sensor changed to OEM and car runs fine ever sice.

Steve Smith
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Re: Opel Corsa D Z12XEP no start

Post by Steve Smith »

Thank you Liviu for sharing this one.

Like there are not enough variables to deal with, here we have non OE parts introducing more curved balls!

The extra dip at the missing teeth looks to comply with the "crossing point" set within the ECU and so be counted as a tooth! (See the solid red line below)
Crossing point
Crossing point
The ECU must have been in complete confusion (with no engine position signal) and we can see the effects from the fluctuation in engine speed based on the varying amplitude of the crank sensor signal (Green dotted line)

Here is an OE sensor from a Vectra Z32SE
Vectra
Vectra
This crossing point issue also raised it's head here https://www.picoauto.com/library/case-s ... ing-lights again with pattern parts!

I hope this helps take care.....Steve

victor2k
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Re: Opel Corsa D Z12XEP no start

Post by victor2k »

Hello,
I think is not the "crossing point" issue is more about how the ECU read the engine speed,please look at the attached file.Using the attached info you will find how the extra dip from the area with missing teeths is readed by ECU as a normal teeth.
Best regards
Attachments
crankshaft signal.pdf
(73.28 KiB) Downloaded 323 times

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vasek
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Re: Opel Corsa D Z12XEP no start

Post by vasek »

Hello.
In the shown fragment from the manual, the points NE - and NE+are mentioned.
This designation is used by TOYOTA.
So we are talking about ECU DENSO.
The NE-point on such an ECU is connected to the hardware ground of the controller.
The signal of the crank-shaft sensor should switch near the reference voltage.
For DENSO, this is 0.03-0.30 volts.
Accordingly, the synchro signals look like this :
Attachments
TOYOTA 1SZ-FE _ DENSO.PNG

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vasek
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Re: Opel Corsa D Z12XEP no start

Post by vasek »

On the OPEL CORSA D with the Z12XEP engine, the BOSCH MOTRONIC ME7.6.2 ECU is installed .
On this ECU, the crank-shaft sensor is connected with an offset of +2.5 volts.
For MOTRONIC ME7.6.2 the reference voltage is +2.5 volts.
This is what the synchro signals on the Z12XEP engines look like :
Attachments
OPEL X12XEP _  BOSCH MOTRONIC ME7.6.2.PNG

liviu2004
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Re: Opel Corsa D Z12XEP no start

Post by liviu2004 »

Great input from everyone, just a mention, that was an oem sensor 13 years old. It’s notorious difficult to get access to its plug from above so I measured only one wire to ground at engine ecu plug.

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