Rough running

[XfireZ51]

Just reviewing the stumble log, what I see is that the secondaries are not opening until 40%+ of TPS opening. MAP kPa is really low at 15 for decel so the motor is operating at the low end of the VE table. Also Spark Advance jumps momentarily from 10d to 25d then drops back to 10 and gradually progresses from there. A bit of Knock Retard as u shut throttle for decel BTW.
Right side running leaner than left for longer period of time, so again I think you r taking a big gulp of air and not compensating for it. O2 sensors appear to be operating nominally. As for replacing them, I have opted for the AC/Delco's rather than the Bosch. Don't know about Denso.

[Billy Mild]

From your oberservations I assume these don't look normal. You are saying that one side of the motor is running very differently than the other side. Right side is leaner than left side.

The spark advance comment I assume means something is out of whack there as well?

I thought the secondaries really only opened IF the motor was over 3000 RPM. Should they also open at a certain TPS setting as well?

As far as my tuning experience I have 0 with FI. I have only tuned 2 stroke motorcycles. Is there a datalog sequence that might be more helpful that what I have gathered thus far.

[XfireZ51]

No I didn't say that. From my observations, it isn't unusual to have one side(typically the driver side) run somewhat leaner than the other. And secondaries come on based on TPS%.
As far as SA, you would need to look at the tables to see if there was some inconsistency or timing anomaly in certain cells, which would not be surprising even for stock calibrations.
As for data logging, I try to do a drive with a variety of elevations and speed trying to come up w about 30k frames. Tuning is an iterative process that zeroes in on a better tune. The objective is to gather data in as many of the cells represented by the VE and SA tables.

[Billy Mild]

Do you try and get some WOT runs and part throttle running when datalogging?

I just feel like I can't be the only person having this issue.

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[XfireZ51]

Originally Posted by Billy Mild

Do you try and get some WOT runs and part throttle running when datalogging?

I just feel like I can't be the only person having this issue.

Sent from my Nexus 6P using ZR-1 Net Registry mobile app

WOT requires use of a WB O2, so no I don't try to do WOT tuning. Besides, the fueling for WOT is dependent on Part Throttle, so PT needs to be correct before moving onto WOT. Also it's safer to do WOT runs on a dyno.

[Billy Mild]

Originally Posted by XfireZ51

WOT requires use of a WB O2, so no I don't try to do WOT tuning. Besides, the fueling for WOT is dependent on Part Throttle, so PT needs to be correct before moving onto WOT. Also it's safer to do WOT runs on a dyno.

Will this datalogging eventually lead to a cause of my stumble?

You mention my car is taking a big gulp of air. I would assume everyone's car would in the same situation, but maybe my tune doesn't have that portion of the VE table tuned in.

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[XfireZ51]

Originally Posted by Billy Mild

Will this datalogging eventually lead to a cause of my stumble?

You mention my car is taking a big gulp of air. I would assume everyone's car would in the same situation, but maybe my tune doesn't have that portion of the VE table tuned in.

Sent from my Nexus 6P using ZR-1 Net Registry mobile app

When u modify the car and enhance breathing, it requires changes to the fueling. With carbs, u would need a bigger pumpshot and larger jets.

[Billy Mild]

Understandable. That's why I had a tune done for the car by Marc Haibecks. Extra fueling for the headers along with a few other mods like removing CAGS.

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[Billy Mild]

I still have this stumble occasionally. Something I noticed is that the INT's are way off side to side, also the MAP sensor is reading around 91 kPa, as well as TPS around 40% or so.

Could this be a faulty MAP sensor causing my issues? Idle seems to be pretty stable overall, but there seems to be one spot in the tune that seems to be an issue. It is usually after slowing down on decel, then give the car a little more throttle below 50% TPS where the car will almost stumble. I do notice that kPa goes really high at this point. I'm guessing that isn't normal.

Thoughts?

Datalog files:
https://1drv.ms/f/s!AmLeM5vTSQEttzvdv7u4r38fklHt

https://1drv.ms/f/s!AmLeM5vTSQEttzxJLTbggfqsgumq

[Billy Mild]

Tonight I did a little more driving with my old school Snap-On MT2500. I set the lights for Closed Loop, Port Throttles closed, and Knock detection. For the the first time since this started I have a common thread, when the stumble occurs after decel, when the car is around 2000ish RPM and I give the car 30-40% throttle, the knock light goes ON, and the car stumbles, the secondaries appear to open as well. Very interesting IMO. So I believe it is due to a knock being detected, now I don't know if there really is a knock.

Unfortunately I don't have a stock chip anymore. Would it be worth test driving with a stock 91 chip to see if anything is different?