Strange injector and timing behaviour?

[DrX]

Anyone have a theory as to what is going on in this log?

I can feel an intermittent "bump"/miss while cruising around 100 KMH. I can also feel significant timing being pulled in a periodic manner.

Taking a look at the log it was obvious that 17 to 18 degrees of timing was being pulled intermittently for no apparent reason. On my tiny notebook I almost missed the similalry periodic dips in INJC2 that probably correspond to the bumps that I was feeling. I am running a OLSD tune. What could cause the bank 1 and bank 2 duty cycles to diverge when there is no trimming? There are also instances at higher throttle positions where it is INJDC1 that dips. Obviously I can't get into the throttle much.

Not sure why it would make any difference but this was more noticeble today after I drained the 114 race gas and refilled with 94 E10. I'm running ID 1000 high Z injectors that come with full data for the EFILive tables. Also running a Roadrunner PCM. It was in RTACS mode today when this issue was really noticeable. I see similar but fewer timing dips in a non RTACS log from yesterday with race gas still in the tank, but I don't see much variance betwwen banks 1 and 2 duty cycles.

[joecar]

Do you have semi-open loop enabled...? Post your tune file.

[DrX]

B4205 is set to 140. B3647 was at 14.12 (EQ 1.0 based on B4205). Not that it will stay there. My understanding was that semi closed loop would not be activated with B4205 maxed.

[DrX]

Forgot the tune file:

[joecar]

SOL activates in the COS when B3647 has cells equal to EQ 1, regardless of B4205...

when SOL activates (when it hits the EQ 1 cells), it uses STFT to trim each bank, I think this is why your IBPW have small variations between banks.

[DrX]

That would explain it. And who knows how good my narrow band sensors are after the race gas! So SOL is active at all ECT temperatures regardless of B4205?

Perhaps the SOL section of the Custom OS tutorial should be updated to remove the reference to 14.63 AFR with respect to B3647 as it is really an EQ of 1.0 that triggers SOL. 14.63 only applies where B3601 is set to that specific value.

[DrX]

I did a clean install of the current builds of V7.5 and V8 today and did some logs with the updated calibration below.

I'm still seeing the unequal blips in INJDC??? It also still wants to "break up" if I lay into the throttle too much.

I did notice that the intermittent timing retardation only occurs if I turn the AC on. Might try logging A/C Compensation Spark next time.

[DrX]

Looks like GM.DYNCYLAIR and DYNAIR are behaving oddly as well.

Here's another log.

[DrX]

I guess my Roadrunner is toast because replacing it with the factory PCM seems to have cured the injector and dynamic airflow issues.

Logging A/C Compensation Spark showed no activity on that PID. So I'm still unsure as to what is pulling timing intermittently when the A/C is on.

[joecar]

Do you get any DTC's when the RR is in...?