For weeks now, we have been trying to isolate what's going on with the car. In 2nd gear, mainly, when I rev up to high rpms it will pop a ton. We've tried boost settings, fuel settings, spark settings, almost everything and nothing seems to make a difference. Tried to record a video of this popping happening.
Here is a link to it: Hopefully someone knows what the heck is going on.
Here's a link to the megasquirt tune file: https://www.dropbox.com/s/xxqd6ie8za...tTune.msq?dl=0

 

Spark blowout? What are your plugs gapped to.

Did you ever add more fuel like what was suggested in your last thread?

https://www.miataturbo.net/megasquir...lp-tune-92145/

Also. post a log.

 

Plugs are now gapped to .020.
Increased the fuel pressure thinking that would provide more fuel and then followed that up with an autotune. Should I just manually increase the fuel in the specific cells in the ve table and not rely on the autotune?

 

idk. post a log

 

I am attaching three logs. The first two are pulls where the popping (misfire?) happens when the RPM is > 4200 and fuel load is > 100%. The third log shows what happens sometimes when just cruising along. I was in 4th gear around 60mph. The AFR was steady around 15.3 and then suddenly dropped to 10.

Any help will be greatly appreciated.

 

if fuel supply is constant and AFR drops, it means you aren't burning something.

 

Don't think so. It's an oxygen sensor. So if you have un-burned oxygen in your exhaust, the AFR will go up, no matter how much un-burned fuel is also present in your exhaust.

 

Yep, unburned mixture will register lean

 

It's your TPS enrichment. This is from the "AFR goes haywire" log. AFR goes haywire, because a lot more fuel gets injected suddenly. This is caused by TPS_accel it seems. Turn that off and try again. Note: Sudden movements of the loud-pedal will likely result in lean mixture and stumbling engine after turning off TPS_accel.

 

sorry, overworked. I remembered while typing that it felt wrong and was counterintuitive.

my bad. happy hour required.

 

Just returned from a tuning run and had some success. Decided to see about lowering the values in the VE table where the misfires occur and things improved. Did a few pulls and paid attention to which cells it was in when the misfires happened and lowered those cells. Eventually, all of the misfires were gone. Does this mean that the whole problem was too much fuel flooding the cylinders?

I still have the random richness when cruising along steady. The AFR gauge looks like a windshield wiper when it happens. I have the acceleration enrichment turned off at the moment. Could this be a grounding issue?

 

The answer to your question is in my above post. Your TPS_Accel is triggered. How did you tune it?

 

So far, the only place I have found anything that looks like TPS_accel is in the Acceleration Enrichment Settings and Wizard. I turned off AE so I figured that would turn off TPS_accel. Guess not.

 

Sorry- I missed the part where you wrote that it's turned off. Post your tune and log, so we can make sure....

 

I now realize I only had the ENHANCED Acceleration Enrichment turned off. I have attached my tune and a handful of logs. I do see in the logs where the sudden drop in AFR follows closely behind a bump in the TPSaccel. Please look over my tune and see if something looks totally wonky. Thanks.

 

It looks like your TPS isn't calibrated. It varies from 0-8%- it should go up to 100%. Bad calibration of TPS leads to random enrichment.
That's assuming you have a TPS and that "TP" in your logs shows the TPS position.

 

After many hours researching online and experimenting with different settings in TunerStudio, I haven't made much progress in eliminating the stuttering that occurs at high RPM and fuel load. I'm attaching my latest current tune and a log of a couple of pulls I did tonight. Please take a look. I appreciate any advice and recommendations.

I long for the day when I can go WOT without any concern.

 

I don't see any logs showing 100% TPS, including your last one. Did you calibrate your TPS as suggested over 3 months ago? Are you actually going WOT?

 

The TPS is calibrated. I'm not going WOT due to the sputtering that happens in boost. You can see the RPMs have a sawtooth pattern when it happens.

 

Just a pro-tip when you have TS open and are running capturing a datalog, you can hit the space bad and that will make a mark in the log file. This makes it easy to pinpoint where problems are.