December 15, 2019, 03:32:00 PM

Author Topic: Issues with my crank sensor on new standalone  (Read 668 times)

Offline wompa164

Issues with my crank sensor on new standalone
« on: November 12, 2019, 11:44:16 AM »
Hi all,

I've recently decided to take the plunge and try out Holley's new Terminator X Max setup. After a frustrating weekend of no starts, I was able to get the car started yesterday (progress!) but it ran very poorly and would die without throttle. Reviewing the datalogs, I can see that the RPM signal intermittently drops to zero and crank sensor errors are generated at the same time.

I initially suspected it was due to sensor voltage differences, but now I'm not so sure - I am beginning to suspect EMI as the culprit. As it stands, my crank sensor wires take a pretty noisy route, past a spark plug wire, next to the starter cable and over the starter.



I can't remember how the wires were originally run but I don't have a lot of slack. Does anyone have any suggestions for better routing or ways I could try to decrease interference? I never had issues with my stock E38 PCM and the shielding on my old harness doesn't really appear any better.

Here is my thread on the Holley forum: https://forums.holley.com/showthread.php?47154-No-Start-RPM-dropping-to-zero-Diag-6-errors&p=222497

Offline Exidous

Re: Issues with my crank sensor on new standalone
« Reply #1 on: November 12, 2019, 02:07:00 PM »
Is the wiring for the CKP shielded at all? I run mine the same way but have shielded wire and the signal is very clean on the MS3.

Also make sure the sensor is getting the proper voltage. Gen 3 and LS2 are 12v. Gen 4 are 5v I believe.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Not too loud with the new resonators!

Offline Cobranut

Re: Issues with my crank sensor on new standalone
« Reply #2 on: November 12, 2019, 06:07:55 PM »
Is the wiring for the CKP shielded at all? I run mine the same way but have shielded wire and the signal is very clean on the MS3.

Also make sure the sensor is getting the proper voltage. Gen 3 and LS2 are 12v. Gen 4 are 5v I believe.

I think those sensors are spec's to run on either voltage.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #3 on: November 13, 2019, 10:50:52 AM »
I have actually tried on both +5v and +12v, but that's a good call. Holley claims it should run on either, something about the sensor's required voltage only being ~3v.

The CKP is shielded, though it could be better. The Holley tech I spoke with didn't seem to think it was an issue with EMI and things I have a bad crank sensor. I am kind of skeptical given the car ran perfectly before installing this standalone; I've got a new sensor coming today so we'll see.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #4 on: November 13, 2019, 02:28:21 PM »
Car fired up right away with the new sensor but still generating errors and RPM is still dropping to zero on my logs. I am communicating with a Holley support member but this sucks given how well the car ran on the stock PCM. This whole kit will be going back to Holley if they can't help me solve it in the next 30 days, which is a real shame given how much promise there is. Teal line is RPM (you can see it spiking down to zero), blue line are crank sync errors being generated.


Offline Cobranut

Re: Issues with my crank sensor on new standalone
« Reply #5 on: November 17, 2019, 04:23:29 PM »
This looks very similar to the problem I had when I installed my MS3PRO.
Ended up being the 24x reluctor wheel on the crank was warped.  I stuck a camera up there and had a friend turn the motor with a ratchet.  The spacing between the wheel halves opened up slightly on one side.
The GM PCM was able to cope with it fine, but the MS3 software wasn't.  :banghead:
Instead of pulling my engine apart to switch to a 58x wheel, I made a spacer and mounted a 36-1 wheel on the damper, bought a 58x sensor and made a bracket to mount it up front, along with an extension harness.
I ended up having to mount the sensor looking at the side of the teeth, as the GM sensor wanted to see a wider wheel than the one from DIY Autotune.
When I do pull the motor down, my intention is to install a 58x wheel in the stock location.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #6 on: November 17, 2019, 04:33:35 PM »
Very interesting, thank you for the feedback!

I figured it could be something like that, I did consider using a camera to do something similar and look for missing teeth or other issues.

How obvious is it that the wheel was warped, do you have a copy of the video I could see?

Itís curious to me that the factory PCM can handle the intolerance. I feel like the tolerance could be accounted for in the software, some degree of error acceptance. There are a number of Holley users who complain about losing RPM under various conditions, though something must be really wrong for it to happen with no load.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #7 on: November 17, 2019, 06:45:37 PM »
Also, was your motor built or otherwise opened up for work prior to your issue?

Mine came from a pullout so itís history is unknown but I have never had mine open other than to install the Improved Racing baffle. Iím trying to imagine reasons why a motor would develop an issue with the reluctor wheel.

Offline Cobranut

Re: Issues with my crank sensor on new standalone
« Reply #8 on: November 17, 2019, 08:06:36 PM »
My motor was built by HKE in Texas.  It's an LS3, but they installed a 24x reluctor to use the simpler LS1 PCM and a cable throttle body.

The GM reluctor is two wheels riveted together.  It looks like one or two of the rivets have loosened and allowed the wheel to separate.

Here's a pic showing the separated side.  180 degress from here the two discs are tight against each other, but I didn't get a pic of that side.
The video I have is over 48Mb, so unfortunately I can't post it here.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #9 on: November 18, 2019, 03:59:37 PM »
I called in to support again today. The guy I spoke with said another team reviewed the logs and agreed that it's losing crank signal. He said he did not see any indication of it being a cam signal issue or EMI.

He asked that I try another new crank sensor before pursuing the next step of sending my ECU in for benchtesting to which I agreed reluctantly. He did mention that the product team is exploring ways to make the system more tolerant of an imperfect crank signal, which I think is what probably needs to happen. Maybe this system can get enough resolution on crankshaft position with the more precise 58x sensors to better handle signal imperfections or works on brand new motors with very tight tolerances, I don't know.

I took a video of the reluctor wheel through the sensor hole and rotated the engine by hand looking for issues with the wheel - I know broken teeth, warping or separation can obviously cause issues. I didn't see anything noteworthy but I'll need to watch it again. I did not see any obvious differences in spacing the way you described, Cobranut.

Offline Cobranut

Re: Issues with my crank sensor on new standalone
« Reply #10 on: November 18, 2019, 10:21:55 PM »
Pretty sure the 58x sensor will not work with the 24x reluctor wheel.  The 24x has 2 sensor elements to read the double row wheel.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #11 on: November 19, 2019, 02:31:33 PM »
No I don't think it will either and that's not what I meant - just that 58x setups seem like they could be more resilient.

I've made a video of my reluctor wheel here, what do you guys think? I don't see any missing teeth or obvious warping, though it's a little hard to tell with the oil: https://imgur.com/a/WHR2PAv

Offline wompa164

Re: Issues with my crank sensor on new standalone
« Reply #12 on: November 25, 2019, 04:39:00 PM »
This has been fixed! The prescribed advice from Holley using an LS3 harness on LS1-style sensors is to flip the cam sensor pins A+C (voltage and signal), which I followed. Apparently that advice is not correct for GTO engines - I flipped it back and it started and idled perfectly.

Offline Cobranut

Re: Issues with my crank sensor on new standalone
« Reply #13 on: November 25, 2019, 10:21:50 PM »
Your reluctor looks fine, unlike mine which had an obvious variation in the space between.

Glad you found the problem.  :bacon:
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.