Porsche 997 Turbo - Engine stopped while highway tuning

[hbcmotorsport]

Alright so this sensor has 3 wires. While monitoring a trace on an02 I took a small piece of wire and jumped out all three combinations. None of them resulted in a change to the reading. Still holds at a constant 4.961v...

That being said this is all factory wiring. The chances of the harness randomly failing in a moderate throttle cruise condition is very slim wouldn't you say?

So, could that an02 input have failed somehow?

[stevieturbo]

I absolutely would not be trying to short out all 3 wires.

But fortunately one of the wires may have been a shield/ground, as well as the sensor ground.

If you were to short a 5v to sensor ground, you risk damaging the 5v line.

I would say the chances of the wiring failing is slim yes, but wires can break at any time.

I would say the chances of an ecu input randomly failing with no causation, is lower. Both do seem extremely unlikely, but neither impossible.

At a minimum, verify continuity from the wires at the sensor, to the ecu. The sync scope you showed, was of a 2 wire VR sensor trace. That is fact. It is not a 3 wire hall sensor which would have a 5v supply.
So I can only say the 3 wires you have are a ground/shield, sensor ground and signal/ANO2

[hbcmotorsport]

Here is what we have so far. I am leaning towards input on the ecu now.

I have confirmed continuity from the harness plug that the crank position sensor plugs into back to the harness plug at the ecu.

I received the new crank position sensor i ordered. I plugged that brand new sensor into the harness in free air while monitoring AN02 on SMon. No initial voltage change. I then passed it back and forth past some ferrous metal, my rear sway bar to be specific. Absolutely no change to the voltage trace. Still sitting solid at 4.961.

At this point can we be fairly certain that it is the ecu? I haven't tried to test the input on the S7 directly since i don't want to risk damaging anything with only some connectors plugged in. But i have continuity to the input pin.

Thanks for all the help so far!

[stevieturbo]

very bizarre.

inputs don't just die for no reason.

As said before, first and easy test is to short sensor ground and the ecu input, which should cause that 5v reading to drop to 0v. ( well 2.5v in this case as it should be set to 5v bipolar and the internal pullup leaves it at 2.5v )

If you do think the ecu input is not ok....you could easily re-pin to another spare input, assuming you have one free. Then just re-assign it in the I/O's

But if it is dead, I'd be wanting to know what killed it.

Or if you have an oscilloscope, or even a multimeter might give you something, hook it up to ground and the wire at the ecu plug at AN02, but de-pin it from the ecu, and see if you can get any sort of a signal in that test. If so, then it would see that the ecu input is no longer happy.

[hbcmotorsport]

I shorted sensor ground and input again just after I confirmed continuity while monitoring an02 on SMon. No voltage change. Just confirmed now that it is indeed set to 5v bipolar.

I suppose I could try pinning it to another input. But like you said, why did this fail? I only have like 10hrs on the ecu. And I was still working on the base fueling map. I wouldn't want the next input to fail too. Also, the spare input I choose also needs a pullup resistor right?

Not knowing the cause of this just doesn't give me the utmost confidence going forward as I was left stranded.

[stevieturbo]

No, setting the input to a setting like 5v bipolar turns on the internal pullup. Same with thermistor.

Not 100% sure what will kill an input. By design, VR sensors do create very high voltages and this is perfectly normal for the ecu to receive, so I can't see it being an overvoltage of some sort having caused it.

But I would want to depin and test to see 100% that you are getting a signal at that pin at the ecu, ideally with an oscilloscope.

Not sure what a dead ecu input would show....but I suspect it would not be the voltage reading you are actually seeing.

You could set it to 5v, and apply a variable voltage to the input and see if you can receive that ( or feed 5v into it ). I'd just struggle to believe the ecu input is dead.
There's just no reason for one to randomly die.

[hbcmotorsport]

First thing i did this morning was try shorting an02 signal at the connector to block ground to verify i wasnt having a harness ground issue. No change to input voltage. Then Ryan suggested trying to unpin and repin to another input. Before doing that i wanted to test i have signal with an oscilloscope like you suggested.

I have unpinned the crank signal wire from the harness and hooked up my lab scope up to it. I have good signal at the ecu pin. There is no reason why the ecu shouldn't at a minimum read the engine as "TURN".

Here is a video.
https://drive.google.com/file/d/1csLILI ... sp=sharing

[stevieturbo]

definitely a good strong signal there.

[hbcmotorsport]

I re-pinned the crank signal wire over to pin D23 and switched the io config to AN03 per Ryan's suggestions. I now have a trigger signal coming into the ecu. However the syncState and runmode still only read STOP. It doesnt even recognize the engine turning even though theres a signal on crank and cam.

https://drive.google.com/file/d/1dKnZOo ... sp=sharing

[stevieturbo]

syncscope

and is the window at the bottom right telling you anything during cranking ? enlarge it to see