Hi,
I have BMW M20 engine with original sensors, ignition and 60-2. Crank errors occur at 7000rpm and engine hits like rev limiter (which is located some distance above). Crank sensor is original, shielded wire, earthed as per instructions. Even the box (S60) is earthed.
Any ideas how to start tackle the problem? It is likely that there are some amount of harmonic vibrations at crank.
Crank errors at certain rpm
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- Posts: 137
- Joined: Tue Jan 16, 2018 9:38 am
- ECU Model: S100 Pro
- Distributor: DTA
- Location: Aberdeen
Re: Crank errors at certain rpm
Is it a two-wire VR type sensor? Any chance you could have the two wires swapped around?
Re: Crank errors at certain rpm
VR type, original Bosch sensor. Wired as per manual, Tyco Raychem stuff.
Engine runs perfectly otherwise, but somewhere near 7000 crank errors occur. Stroked BMW M20's are known to have harmonic vibration issues, so I'm primarily expecting that somehow being the rootcause. But how to tackle that?
I think I'll try to put some more airgap first (now it is sdt 1.0mm). But I'd be interested what the filter setting at General - menu does? Product manual is not really informative explaining the phenomena that the setting is made for.
Has anybody tested using resistor in the signal wires to reduce the voltage?
Engine runs perfectly otherwise, but somewhere near 7000 crank errors occur. Stroked BMW M20's are known to have harmonic vibration issues, so I'm primarily expecting that somehow being the rootcause. But how to tackle that?
I think I'll try to put some more airgap first (now it is sdt 1.0mm). But I'd be interested what the filter setting at General - menu does? Product manual is not really informative explaining the phenomena that the setting is made for.
Has anybody tested using resistor in the signal wires to reduce the voltage?
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- Posts: 3588
- Joined: Tue Aug 02, 2011 12:08 pm
- ECU Model: No ECU
- Location: Norn Iron
Re: Crank errors at certain rpm
I cannot imagine a resistor doing the signal any favours at all.
If you want less voltage, larger air gap.
Ideally a scope trace when the problem is occurring would let you see if the signal is good and clean or not.
If you want less voltage, larger air gap.
Ideally a scope trace when the problem is occurring would let you see if the signal is good and clean or not.
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- Posts: 38
- Joined: Sat Jul 30, 2011 4:35 pm
- ECU Model: S100 Pro
- Distributor: JON-TEC-RALLYE
- Firmware Version: 89
- Location: Canary-Island
Re: Crank errors at certain rpm
good morning, my experience with this type of error, is to bring the sensor closer to the pulley, in that bmw 20 model it is fixed and the adjustment is not possible, check if the pulley is centered since it is mounted on rubber and it is common for it to faded with years of use.
the configuration to be 60-2 and filter 2000.
rpm sensor connector. wire order.
pin 1 signal.
pin 2 ecu ground
pin3 chassis ground shielded cable.
If it doesn't work, simply replace the sensor.
the configuration to be 60-2 and filter 2000.
rpm sensor connector. wire order.
pin 1 signal.
pin 2 ecu ground
pin3 chassis ground shielded cable.
If it doesn't work, simply replace the sensor.
DTA--MoTec--Link--Ecumaster--HONDATA
Re: Crank errors at certain rpm
I increased airgap from 1.2 to 1.4mm. During first acceleration test engine turned to rev limiter (7500) withour errors. Then during subsequent trials it hitted crank errors approximately at 7000-7200.
Increasing airgap made very small difference, but did not solve the problem.
Next time I think I try to alter the filter values.
Increasing airgap made very small difference, but did not solve the problem.
Next time I think I try to alter the filter values.
Re: Crank errors at certain rpm
New sensor made no difference.
1.85mm air gap makes engine run flawlessly to current redline 7500rpm. I have no idea why it loves so big cap. Factory gap is about 1mm.
1.85mm air gap makes engine run flawlessly to current redline 7500rpm. I have no idea why it loves so big cap. Factory gap is about 1mm.
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- Posts: 3588
- Joined: Tue Aug 02, 2011 12:08 pm
- ECU Model: No ECU
- Location: Norn Iron
Re: Crank errors at certain rpm
Maybe a lot of movement with the crank or something ?
But if it works it works.
But if it works it works.
Re: Crank errors at certain rpm
This is good saying!
I'd still be curious to understand what the "filter" setting does and what is the theory behind it. I understand that some of the settings are hard to explain for the ECU manufacturer and they perhaps do not want uneducated "tuners" to mess with settings... but anyway.
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- Posts: 3588
- Joined: Tue Aug 02, 2011 12:08 pm
- ECU Model: No ECU
- Location: Norn Iron
Re: Crank errors at certain rpm
I just wish all ecu makers would incorporate a scope that records a trace when it has come across errors, or just an ability to view a proper scope trace of the crank/cam patterns.
At least then it gives you a proper visual to try and diagnose what about it is making the ecu unhappy.
Without a scope trace, you're largely working blind.
or of course you can hook up an external scope to see.
At least then it gives you a proper visual to try and diagnose what about it is making the ecu unhappy.
Without a scope trace, you're largely working blind.
or of course you can hook up an external scope to see.