Upgraded to V4...now getting sensor dropouts

[AWH]

Greetings,

I recently sent in my PRB ECU to be upgraded from V3 to V4 KPro. It came back with firmware installed that required me to move to the current Beta version of KManager (4.5.8.0).

Since then, I have been seeing regular sensor dropouts in the datalogs. Nothing else has changed on the car. The weird part is that the occurrence seems to be time related...always at 6:29 in the log.

I tried disabling the VSS since it is sometimes has spikes due to the age of the sending unit (CRX dash), but saw the same result.

I also tried running open loop and...same.

The car is a K-swapped CRX (OneLapCRX.com). The car was towed to the track and run for relatively short sessions. One out lap, three hot laps, two cool downs. Two different days.

I'll attach the kal and a series of datalogs demonstrating the issue in subsequent posts. This first one was the very first session and it was fine.

--Andy Hollis

[AWH]

Second session out, I start getting weirdness. VSS, MAP, TPS all drop in unison. ECU then commands weird CAM angles.

First starts at 5:33, then again at 6:19 and 6:29.

BadVSS1.png

BadVSS2.png

[AWH]

Note that the car seemed to be running fine through all of this.

I went back a couple days later with a plan to be more consistent and try testing some possible causes.

Session 1 was run as before, and got same result at 6:29.

Day2BadVSS.png

[AWH]

Thinking that maybe the VSS was the cause (signal drops out causing car to think it is not moving and pulling cam timing to 0, etc)...so I disabled the VSS.

Same result...though you can see the VSS being held at a constant 49mph (as it should) ...and then dropping to zero.

Day2NoVSS.png

[AWH]

What I really didn't like was that the datalogs showed the AFR's to spike incredibly lean in a couple of tables spots during these episodes. Not sure if real or not, so I tried running open loop with no VSS. Still same result at same place.

Day2NoVSS_OpenLoop.png

[AWH]

I'm starting to wonder if this is a real engine control problem, or just a datalogging problem.

Previously with V3, I've datalogged at the max of 20hz. Now I'm at 100. It's the only change I can think of.

I'm open to suggestions on things to try.

I'll be on track again Friday and Saturday for some testing/recon. We are running this car in the One Lap of America in a couple of weeks.

--Andy

PS: If you want to tighten the communication loop, Doug has my number.

[Spunkster]

Having our software engineer take a look at this.

[AWH]

Quick update…at a different track today. Unchecked the 100hz logging box and went to original kal with VSS and closed loop turned on.

No issues.

So it appears to be only a logging issue, not a engine control problem.