No Start - RPM dropping to zero + Diag 6 errors.

[wompa]

GCF attached: MPFI_8ZAAGN.zip

[81 TransAm]

For some reason, your Global File doesn't work for me.

[wompa]

Did you unzip it? Opened with the latest Terminator X software?

[AmateurTouring]

Brand new ACDelco crank sensor arrived from Summit this morning. I threw it in and it fired right up, still running terribly and wants to die without throttle. CRANK_ERROR_counts are still showing up in the datalog and RPM reading drops to zero.
Attachment 8914

The CAM sensor can cause these problems too. Including the weird RPM readings and crank_error.

[wompa]

Wouldn't such cam signal issues manifest in the datalog on Diag #7 per this post? https://forums.holley.com/showthread...s-amp-Datalogs.

My datalog is flat for Diag #7, max count of 0. I'm not going to replace another sensor in blind faith that it will solve the issue until I hear more from Holley. I exchanged a few emails with Dustin in Support yesterday, who asked "Have you verified that you have a 1x cam? It appears to be missing a rotation on the crank." Again, stock engine that ran perfectly on the stock E40 PCM.

[AmateurTouring]

"Cam sensor" was the wrong thing to say. The cam signal can cause those running issues. Either the sensor, wiring or computer settings not matching the parts on the engine. I agree it's probably not the sensor specifically, but the cam signal might be worth looking at.

[Danny Cabral]

https://forums.holley.com/showthread...511#post219511 (Related Forum Post)

[wompa]

I called in again today and spoke with Dustin. He said another team reviewed the datalogs and agreed that it's losing crank signal. He said he did not see any indication of it being a cam signal issue (Diag #7 in the datalog) or EMI.

He asked that I try another new crank sensor before pursuing the next step of sending my ECU in for bench testing, 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 engines 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'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. I see a few spots with discoloration, not sure if that's caused by buildup or heat or what.
https://imgur.com/a/WHR2PAv

[wompa]

This appears to now be a solved issue! A big thank you to Ethan in support for suggesting I review the cam sensor. I found this post just earlier this morning that mirrors my setup pretty closely and tried re-switching the cam sensor wiring A & C pins (reverting Holley's advice) and it fired up immediately and seems to run well and rev freely, I'm over the moon. Datalogs are perfect, no crank errors and RPM is steady.