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Engine speed signal missing / on which connector in the engine compart

996electric
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996electric Member

996electric

Posted
Posted

Hello,

Im new in this forum and I decided to go to this forum, because I could see lots of technical information and guys who have knowledge of the car, which is not always present in other ones.

Short introduction:

Im actually converting my private 996 to electrical drivetrain. I did this already with my BMW Z3 (which has the same connector as the 911 which is labeled with BMW on it...

But the 911 has two round big connectors in the trung X59/1 and X59/2.

I figured out that the signal should be present at 9(+ signal) and 10 (ground).

But it does not work on both.

Does anybody have a layout, which signal is on which pin of these two connectors and which one is 1 or 2?

Thanks in adavance!

post-95239-0-77361600-1396466002_thumb.j

Ahsai Member

Ahsai

Posted
Posted

How did you test the signal? Did you tap into those wires when the engine is running? The pin numbers are correct for both DME5.2.2 and DME7.

You used a scope or multimeter?

Ahsai Member

Ahsai

Posted
Posted

I think I understand your issue now after re-reading your post. Looks like you try to measure the signal from the DME side of the connector with the connector (therefore the crank sensor) unplugged. The crank sensor is of the 2-wire magnetic type that generates it's own signal to the DME so no power or signal is supplied by the DME.

http://www.underhoodservice.com/Article/95427/tech_feature_understanding_the_differences_challenges_between_crankshaft_position_sensors.aspx

996electric Member

996electric

Posted
  • Author
Posted

Hi, its a Carrera c2 from year 1998.

I don't have the engine anymore. I could Figure out that the signals are on the bottom connector. When I put a square wave signal in oft about 600 Hz, funny things are happening linke flicking check engine light and random RPM signal.

How dos the crankshaft signal work is it linke 58-2 signal? So like 60 pin square wave and the last two ones flat?

Ahsai Member

Ahsai

Posted
Posted

Hi, its a Carrera c2 from year 1998.

I don't have the engine anymore. I could Figure out that the signals are on the bottom connector. When I put a square wave signal in oft about 600 Hz, funny things are happening linke flicking check engine light and random RPM signal.

How dos the crankshaft signal work is it linke 58-2 signal? So like 60 pin square wave and the last two ones flat?

Ok, so you are trying to simulate the crank Signal. I would try a sawtooth wave instead with the last 2 teeth at higher voltage.

http://www.picoauto.com/waveform/Sensors/Crankshaft/wave107.html

Try at your own risks though :)

996electric Member

996electric

Posted
  • Author
Posted

Hi,

the graph is really good, it indicates the 60-2 signal or in this case! You can count 58 spikes and than a gap (the two times gap) and than the signal starts again. The question is how the 911 does this signal...

So I don't have the engine anymore, does anyone have a scope trace about it? I have to program my arduino to simulate this signal.

When I got it right, I can convert simply the engine speed sensor signal to this one and the ECU gets the original signal.

If any other values are needed for the ECU like HFM or throttle position, I have to think how to simulate them.

Ahsai Member

Ahsai

Posted
Posted (edited)

The signal is generated by the magnetic type sensor that points to the teeth of the flywheel like in the 1st link I posted.

I'm sure the waevform is described in the repair manual (you got one?). I found an old post here talking about it.

The flywheel has 60 teeth positions but only 58 physical teeth. The two missing ones generate the spikes in the signal.

http://www.renntech.org/forums/topic/40945-cam-position-sensor-resistance-readings/?p=217349

Is the reason to simulate the other sensors just to keep the DME happy and not trip the CEL? If so, it would be a fun project...just think about how to fool the O2 readings, MAF, etc.... I can understand you want to reuse the instrument cluster, which makes sense. I can see you reusing the voltage gauge, speedo, odo, tacho, engine temp with proper sensor or sig processing like the tacho.

Edited by Ahsai
996electric Member

996electric

Posted
  • Author
Posted (edited)

Yes thats the plan.

A colleague is now working on the signal 60-2,

Im actually figuring out what is necessary for the oil pressure gauge to run.

On Pin 16 and 17 I did not have luck with a poti. I know already the pressure should normally be 19 Ohm when the engine is not running so 0 as value. But it is always going over 5 bar. So it looks like there is an information missing. But I could also read the oil level sensor is independend.

Current situation:

Speedometer - ok

Battery voltage 12V - ok

Oil level measurement - not needed anymore

Oil pressure measurement - could be useful - not working up to now with pin 16 and 17.The range should be 10-180 Ohm, 19 for 0bar..

Engine speed signal - in operation.

Edited by 996electric
996electric Member

996electric

Posted
  • Author
Posted

And yes it's a fun project. Im driving the BMW now since more than 10000km with great fun, much better than before.

The Porsche will be equivalent than before. Thats enough for me.

Ahsai Member

Ahsai

Posted
Posted

Oil pressure measurement - could be useful - not working up to now with pin 16 and 17.The range should be 10-180 Ohm, 19 for 0bar..

My guess is a poti betwen pin 16 and ground since the pressure sensor is metal and it's grounded by screwing into the engine block.

996electric Member

996electric

Posted
  • Author
Posted

Ok, I will figure out this afternoon. Do you know where to find analog ground? Some signals are referencing to it which are through the connector X59/2 and separately to analog ground. I guess it is ground of chassis but im not 100% sure. I have to try.

Ahsai Member

Ahsai

Posted
Posted

Ok, I will figure out this afternoon. Do you know where to find analog ground? Some signals are referencing to it which are through the connector X59/2 and separately to analog ground. I guess it is ground of chassis but im not 100% sure. I have to try.

There are quite a few ground points on the DME for different sensors. See the DME 5.2.2 pinout here

http://www.renntech.org/forums/topic/28597-porsche-996-dme-pinouts-and-connectors/?p=151444

996electric Member

996electric

Posted
  • Author
Posted (edited)

Very interesting:

Between 16 and 18 is the signal. It has an ohmic range from 5 bar equals 219 Ohm, 0 bar equals 9 Ohm.

So simply connect these two signals together and you'll getting it to work.

Edited by 996electric
Ahsai Member

Ahsai

Posted
Posted

Very interesting:

Between 16 and 18 is the signal. It has an ohmic range from 5 bar equals 219 Ohm, 0 bar equals 9 Ohm.

So simply connect these two signals together and you'll getting it to work.

That's because 18 is the ground :)

  • 10 months later...

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