wiring suggestions/best practices for VR crank sensor

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wndrllama103
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wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

Hi all,

For the entirety of my MS3Pro experience, I've been having interference problems on my VR crank sensor on my 2001 VW 1.8T. I recently made some progress by separating out the harness into two harnesses (I had combined them for convenience originally, not thinking about interference), and using copper foil shielding tape on the crank sensor wire. Now I'm able to get to 5500 rpm before it breaks up, so I'm making progress.

The error I'm getting is "error #2: unexpected missing tooth"

It's a 60-2 bosch, stock sensor + plugs from the donor car. I'm using the full 8' length of the flying lead harness (it's a mid-engine car, and for some reason I put the ms3pro under the dash instead of on the firewall...). I've spliced the stock plugs to the ms3pro harness so I can use the stock sensors.
On the crank sensor, I'm running a 10K resistor across CKP +/- pins 1/2 respectively, and the ground is hooked up to pin 3. I'm using 3m glued butt connectors for the splices, and I've wrapped the entire wire from beginning of the splice to the plug in copper foil shielding tape, then in electrical tape, and protected with nylon. There is pro
bably <1" of unprotected wire under the rubber boot on either side. This wire is run under the intake manifold.

I'm looking to get to 7K rpm (for starters). What else can I try? up the resistance? noise filters (seems unlikely for high rpm)? Are the wires simply too long (doubtful)? shield the entire harness?

I'm seeing some interference on my VSS as well, which is obviously less of an issue. That's hooked up to pwm idle out 1 with absolutely no shielding, so I'm not surprised. Could that be introducing an issue?

Thanks for any suggestions.
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Re: wiring suggestions/best practices for VR crank sensor

Post by racingmini_mtl »

Actually, you might want to lower the resistance instead of increasing it. You may need to go down to 1k or even 510 Ohms. But start higher (between 1k and 10k) and go down from there if you need to. If you go too low at some point you're going to lose the signal at low RPM.

Jean
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wndrllama103
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

racingmini_mtl wrote:Actually, you might want to lower the resistance instead of increasing it. You may need to go down to 1k or even 510 Ohms. But start higher (between 1k and 10k) and go down from there if you need to. If you go too low at some point you're going to lose the signal at low RPM.

Jean
Interesting. I always thought that more resistance helped clean up the signal.
wndrllama103
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

racingmini_mtl wrote:Actually, you might want to lower the resistance instead of increasing it. You may need to go down to 1k or even 510 Ohms. But start higher (between 1k and 10k) and go down from there if you need to. If you go too low at some point you're going to lose the signal at low RPM.

Jean
Would I be able to see any evidence of this in a log? What should I look for?
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Re: wiring suggestions/best practices for VR crank sensor

Post by whittlebeast »

I had a hard to start car running a 36-1 We converted to 36-2 and all of the error 2 went away. See if the code will take 60-3 in the settings and restart the ECU. If the fuel pump comes on for 2 sec and ten stays off, you should be good to go. Just grind off the the tooth next to the 2 that are missing now.

The programmers may chine in here. I just tried it on my computer and all appears to be good.

Andy
wndrllama103
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

whittlebeast wrote:I had a hard to start car running a 36-1 We converted to 36-2 and all of the error 2 went away. See if the code will take 60-3 in the settings and restart the ECU. If the fuel pump comes on for 2 sec and ten stays off, you should be good to go. Just grind off the the tooth next to the 2 that are missing now.

The programmers may chine in here. I just tried it on my computer and all appears to be good.

Andy
>> Just grind off the the tooth next to the 2 that are missing now.

That sounds pretty invasive; If audi can get it running with 60-2, I don't see why ms3 can't. Either way, the car starts just fine, and revs fine all the way to 5500 rpm.
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Re: wiring suggestions/best practices for VR crank sensor

Post by racingmini_mtl »

The issue with the 60-2 signal is that in some cases you get a spurious tooth detected in the missing teeth area. With a lower resistance, it lowers the signal and this is no longer detected as a tooth.

Jean
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Re: wiring suggestions/best practices for VR crank sensor

Post by Paul_VR6 »

On pro the ckp cable is already shielded. On the 1.8t like all vw the shield is carried through the connector on a separate pin and should be enough for noise. Whatever you may have done with a foil wrap won't do anything as a shield unless its grounded. It could be making things worse.

I would make sure the noise filter is completely off first.

Second if there is noise on the vss you likely have a ground issue that you need to fix. Make sure you are following the grounding recommendations in the manual.

Check the crank sensor face for debris. If you have a non oem crank sensor, it may be an issue as well.

Failing any of that fixing it I would go to the resistor. I have used 10k on every pro install on vw/audi 60-2 and its pretty reliable.
-Paul
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wndrllama103
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

Paul_VR6 wrote:On pro the ckp cable is already shielded. On the 1.8t like all vw the shield is carried through the connector on a separate pin and should be enough for noise. Whatever you may have done with a foil wrap won't do anything as a shield unless its grounded. It could be making things worse.

I would make sure the noise filter is completely off first.

Second if there is noise on the vss you likely have a ground issue that you need to fix. Make sure you are following the grounding recommendations in the manual.

Check the crank sensor face for debris. If you have a non oem crank sensor, it may be an issue as well.

Failing any of that fixing it I would go to the resistor. I have used 10k on every pro install on vw/audi 60-2 and its pretty reliable.
>> Whatever you may have done with a foil wrap won't do anything as a shield unless its grounded. It could be making things worse.

I removed all the shielding/casing from the stock plug, and continued the shield from the from the CKP cable all the way to the end (well, within an inch of the end anyway). I attached the ground from the CKP cable to the ground pin on the OEM plug. I did this because I couldn't separate the shielding from the insulation on the OEM wire. After I was done, I checked that the foil was grounded the entire way.

Does this still sound ok? It seems like this last change got me to 5500rpm. Before I was breaking up at 3700.

>> Make sure you are following the grounding recommendations in the manual.

I am as far as I know.. All (5?) ground wires from the ecu meet at the same point on the block, and I spliced that into a ground on the head and the body.

>> Check the crank sensor face for debris. If you have a non oem crank sensor, it may be an issue as well.

I will do this. This is an OEM crank sensor that probably has never been removed from the block.

>> I would make sure the noise filter is completely off first.

It is.
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Re: wiring suggestions/best practices for VR crank sensor

Post by Paul_VR6 »

Not sure I understand your shielding, take a few pics.

Also try moving ms grounds to battery negative.
-Paul
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billr
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Re: wiring suggestions/best practices for VR crank sensor

Post by billr »

What I have seen is a 60-2 "morphing" into a 60-3 at different rpms. (Same for 36-1 => 36-2) Like Jean says, the amplitude of the trailing part of the gap signal varies. Making the gap "filled" instead of "missing tooth" seems to solve this. Note that Electromotive has been making their 60-2 wheels with the gap half-filled for quite some time now. I have never tried the half-filled, but know a complete fill turns a 60-2 into a reliable 60-3. Yes, MS/TS accepts 60-3 fine.
wndrllama103
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

billr wrote:What I have seen is a 60-2 "morphing" into a 60-3 at different rpms. (Same for 36-1 => 36-2) Like Jean says, the amplitude of the trailing part of the gap signal varies. Making the gap "filled" instead of "missing tooth" seems to solve this. Note that Electromotive has been making their 60-2 wheels with the gap half-filled for quite some time now. I have never tried the half-filled, but know a complete fill turns a 60-2 into a reliable 60-3. Yes, MS/TS accepts 60-3 fine.
I haven't taken a tooth log with this happening yet, but that's kind of what it looked when I was having crank interference issues at lower rpms.
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

Paul_VR6 wrote:Not sure I understand your shielding, take a few pics.

Also try moving ms grounds to battery negative.
I can't take any pictures at this point, it's all wrapped up. I'll try to explain again.

I removed about an inch of the plastic insulation from CKP, leaving the foil intact.
I removed *all* the shielding/insulation from the VW connector.
I spliced CKP +/- to pins 1/2, and CKP ground wire to pin 3, and have a 10K resistor across pins 1/2. All done using 3m heat shrink + glue butt connectors.
I then wrapped the wire, starting at the CKP foil, with adhesive copper conductive tape all the way to the plug end.
I then wrapped the entire wire, starting before the CKP insulation break, to the plug end.
The copper tape is conductive on both sides, with conductive adhesive.

>> Also try moving ms grounds to battery negative.
I thought documentation said to mount this to the block. This wouldn't be a fun exercise for my setup, especially just as a test. It would involve a lot of re-wiring.
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

I took a data log of the high rpm breakup (slow accel in first up to ~5.5K)

One thing that's odd, is that everything that runs off the 5v reference voltage (TPS, MAP, VSS1) seems to have a blip at the same time. This definitely isn't helping my situation, but I don't know if it's the cause. Would this be from a poor ground (I don't understand how I'd have a poor ground, but I guess it's possible)? I'm not sure how to trouble shoot these things. I'm just guessing.

The only wires that are shielded in the harness are the CMP/CKP wires. What's to stop interference from getting to the rest of the sensors? I'm obviously no EE.

I can't seem to catch a tooth log with the miss... here's a pic.
tooth.log.missing.teeth.high.rpm.png
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Re: wiring suggestions/best practices for VR crank sensor

Post by billr »

Hey, I should clarify that my observations about missing-tooth wheels is only using the standard V3.0 tachin circuit. Since this thread is about a Pro, my comments may not be pertinent...
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

So, I'm still having issues with my sync loss at high rpm

My last setup was breaking up around 5400rpm.

Since then I did the following:
- Installed a new bosch crank sensor; no change
- Installed a new plug end from Audi (the wires weren't the best on the original one, and it was also 17 y/o) - after this change the engine started breaking up at 3700rpm
- Tried running a 1K resistor - no sync at crank
- Tried running a 20K resistor - same result as 10K (breaks up at 3700 rpm)

Am I doing something wrong with the splicing/shielding? Maybe I got lucky before when it was able to get to 5400 rpm. I took pictures this time, maybe I'm doing something stupid.
https://photos.app.goo.gl/WrsHW1U3C1oQexLf1

I'd like to grab a tooth log while this was failing, but for some reason the tooth log is restricted to 4s, which makes life really difficult. I could have sworn I saw the voltage dropping on the tooth log while I was driving, but I'm not sure. It was 11pm when I took these logs, and neighbors aren't too happy about high revving engines at this hour. I'll try to get a tooth log while it's failing.

Anyway, I'm running out of things to try. I'll try a 5K resistor next, unless someone has some other idea.

Thanks for any help/ideas
Attachments
2017-10-18_23.06.05-20k.toothlog.csv
tooth log
(123.98 KiB) Downloaded 37 times
2017-10-18_23.05.17-20k.crank.csv
composite log
(365.98 KiB) Downloaded 30 times
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Re: wiring suggestions/best practices for VR crank sensor

Post by billr »

Am I correct that you can't easily try making the crank wheel a "filled gap" config because it is an integral part of the crank or flywheel?
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Re: wiring suggestions/best practices for VR crank sensor

Post by MegaMicra »

Instead of putting the resistor in parallel with your vr+ & vr- wires, have you tried putting your resistor inline with only the vr+ wire.

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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

billr wrote:Am I correct that you can't easily try making the crank wheel a "filled gap" config because it is an integral part of the crank or flywheel?
I'm a noob here, so I don't really know what you mean by a "filled gap" config.

But yes, the wheel (60-2) is an integral part of the crank.
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Re: wiring suggestions/best practices for VR crank sensor

Post by wndrllama103 »

MegaMicra wrote:Instead of putting the resistor in parallel with your vr+ & vr- wires, have you tried putting your resistor inline with only the vr+ wire.

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I haven't tried that yet. What would you suggest for a resistance?

I don't know if it's significant or not, but I am using the full 8' length + plug (so ~6") of the wire.
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