Opel c20xe need help

[Rapa]

Trigger Scope Log 2022-06-11 3;54;52 pm.llgHello guys. Sorry for my english))

Try to explain my proplem.

I have drag race car with opel c20xe engine. linc fury ECU. ignition 4 AEM smart coil, crank sensor- stock reluctor (gap change from 0,8 to 0,4mm), trigger wheel 60-2, cam sensor- hall, installed on cam shaft. Fuel we used Q16 AFR 10,5-10.7

problem start with RPM rising. 

RPM limit activated accidentally, in area 8000-9200rpm, we need to rotate 9500rpm.

in log it shows abnormal rpm numbers like 16000rpm, 64000rpm

wiring polarity checked according manual (NEG and SHIELD on SHIELD/GROUND, "+" on TRIG1), wire "one pice" from sensor to ECU.

Trigger filter 1, try 4- no help.

in the FAQ tolds about OEM trigger whell problem with "missing tooth", we modify it (see attach), nothing change.

On oscilo its picture on dyno approx 8500rpm.

arming thresold move up and down, nothing changed. 

one thin- we change DWELL time on the coil from base 3 to 5, it moves our problem approx on 1000rpm upper (before rpm limit activate on 7800-8000rpm)

which way do we need to go?

 

 

Trigger Scope Log 2022-06-11 3;54;52 pm (1).llg Log 2022-06-11 4;50;17 pm.llg

[Adamw]

I would say the most likely cause is the minimum voltage after the first tooth (green line) creeps up as RPM increases until it no longer crosses zero.  

I like your idea with welding the extra metal into the gap, but I suspect due it being a separate piece of metal the ferromagnetism doesnt work like a single piece of iron.   I have seen weld repaired teeth completely mess up the signal.

To bring the green line down lower in voltage what we need to do is reduce the maximum voltage as the first tooth is approaching the sensor (yellow line). 

1. You could try increasing air gap which will lower all voltages.  I have doubts whether this will help much.
2. You could try adding a resistor inline (series) with the trigger 1 wire.  You will need to experiment with resistance value but I would say 3K-10K would be what I expect would help the most.
3. You could try adding a resistor across the sensor +/- wires to apply some load.   Again resistance value will need some experimentation but it will be lower in this case, more like 300ohm at a guess.

Another option, you may be able to drill out the center of the OEM sensor and screw a hall sensor into it.  Something like ZF GS100702 usually work ok with small 60-2 teeth (they need a stronger pull up resistor for high tooth count).  

 

[augusto]

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto

sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto

sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto.
sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augustus,
sorry for the text or in english

[Rapa]

4 hours ago, augusto said:

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto

sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto

sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augusto.
sorry for the text or in english

Hello everybody
It would be better to use a hall sensor rather than reluctance.
Attached is a photo of my c20xe engine.
Augustus,
sorry for the text or in english

Hello, what p/n sensor? which max rpm do you use? 

[Rapa]

17 hours ago, Adamw said:

I would say the most likely cause is the minimum voltage after the first tooth (green line) creeps up as RPM increases until it no longer crosses zero.  

I like your idea with welding the extra metal into the gap, but I suspect due it being a separate piece of metal the ferromagnetism doesnt work like a single piece of iron.   I have seen weld repaired teeth completely mess up the signal.

To bring the green line down lower in voltage what we need to do is reduce the maximum voltage as the first tooth is approaching the sensor (yellow line). 

1. You could try increasing air gap which will lower all voltages.  I have doubts whether this will help much.
2. You could try adding a resistor inline (series) with the trigger 1 wire.  You will need to experiment with resistance value but I would say 3K-10K would be what I expect would help the most.
3. You could try adding a resistor across the sensor +/- wires to apply some load.   Again resistance value will need some experimentation but it will be lower in this case, more like 300ohm at a guess.

Another option, you may be able to drill out the center of the OEM sensor and screw a hall sensor into it.  Something like ZF GS100702 usually work ok with small 60-2 teeth (they need a stronger pull up resistor for high tooth count).  

 

Hello Adam. Thanks a lot. 

way #1 increasing the gap not effective, allready done many times.

way #2 and #3, i think it s too much expiriments, result is accidental (all the more so OEM crank trigger whell installed inside the  engine block, dyrictly on a crankchaft )

I guess the best way is change the thrigger wheel (replace it from engine block) and sensor type (for example hall sensor). 

What do you think about? If you are agree whith me, what design of trigger wheel and sensor type are preferred for 100% guarantee of effective work on 9500-10000rpm?

 

[Rapa]

23 hours ago, Adamw said:

I would say the most likely cause is the minimum voltage after the first tooth (green line) creeps up as RPM increases until it no longer crosses zero.  

I like your idea with welding the extra metal into the gap, but I suspect due it being a separate piece of metal the ferromagnetism doesnt work like a single piece of iron.   I have seen weld repaired teeth completely mess up the signal.

To bring the green line down lower in voltage what we need to do is reduce the maximum voltage as the first tooth is approaching the sensor (yellow line). 

1. You could try increasing air gap which will lower all voltages.  I have doubts whether this will help much.
2. You could try adding a resistor inline (series) with the trigger 1 wire.  You will need to experiment with resistance value but I would say 3K-10K would be what I expect would help the most.
3. You could try adding a resistor across the sensor +/- wires to apply some load.   Again resistance value will need some experimentation but it will be lower in this case, more like 300ohm at a guess.

Another option, you may be able to drill out the center of the OEM sensor and screw a hall sensor into it.  Something like ZF GS100702 usually work ok with small 60-2 teeth (they need a stronger pull up resistor for high tooth count).  

 

Actually we cheked smth, before link installiation we use other ECU, with all current configuration, everything was ok. Old ECU has resistor on inlet signal crankshaft trigger 470kOm, link, i found 22kOm,  i guess its a possibl reason of it?

[Adamw]

How much effect the series resistance has will depend of the total impedance of the input circuit.  Addin more resistance should help the high RPM problem, but of course will also lower the voltage at low RPM.  So if you go too high the engine wont start.

[augusto]

Hello
Jetta hall vw sensor, this engine worked at 8500 rpms without any failure.

Augusto.

[Adamw]

If you are making a trigger wheel I would go for a 24-1. for a high RPM engine.  Most motorcycles use 12 or 24T.

At low tooth counts like 2 or 4 you will see the timing advance a lot under heavy transients - like 10+ deg advance, this often results in transient knock or you have to run weaker than ideal advance .  By about 12T you can only see 1 or 2 deg drift with a hard acceleration.  At 24T the drift under transients is difficult to detect by eye.  Beyond 24T you dont see much further improvement with G4+.

I generally prefer VR sensors since they have a better signal to noise ratio at high RPM where it is important, but a Hall sensor is perfectly fine and not uncommon.  As a general comment it is easier to find aftermarket/industrial type sensors with easy mounting options in hall effect, VR sensors usually come from OEM applications so often have more complicated mounting arrangements.  

[Rapa]

Thanks for recomendations, first we decide to try with resistors. 

look at attachment, its 8100rpm with 120kOm resistor on the positive wire, looks pretty good? 

 

[Adamw]

Yep crank certainly looks much better in that scope.     

[Rapa]

today we will try to implement 220kOm resistor, result will be here

[Rapa]

420kOm 9300rpm

[Rapa]

4 hours ago, Rapa said:

420kOm 9300rpm

Adam, is it success? Time to road tune?

[Rapa]

for whom it s intresting:

the problem was solved by trigger wheel replaced from crankcase, and new trigger wheel design is 24-1