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Old 06-14-2018, 05:55 PM   #1  
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Default rich-flicking afrs and stumbling engine

Setup: 1.6, T25 with 3" exhaust, FF 640s, brain-built MS3x
Context. Turbo was put in a couple weeks ago. Wastegate wired open to tune VE tables for new exhaust and whatnot.
Made a whopping 3 psi at redline in 4th gear in that configuration. No real issues to speak off, the car loved it. So I put the pin in the wastegate to go onwards to retuning it for big boy boost (stock T25 wastegate, 7-10psi...?) and I was taking it really easy, only pulling to ~110 kpa, then 120, 130, 140, making sure my AFRs were good the whole time. A bit rich at first (9s-10s), but VEAL was working. I did a short, light 5th gear pull at around 3k rpm up to 140kpa and after i let off, the engine was hesitating and jumping, all the while my AFRs flicking rich by ~2.5 points.

I limped it back home while datalogging, and it seemed like any acceleration triggers it, but steady cruising seems to relax it.
Judging by the log, my injectors are firing sporadically, but the wiring for them is good and nothing is exposed. I couldn't find any recent threads of similar issues, so I'm assuming this is a software issue. I also trust FF injectors not to be caddywompus after <6 months of use
This happened before, about 4 months ago when the car was N/A (same injectors) and I chalked it up to bad gas because it went away on its own, but the log from then looks pretty much the same.
Suggestions or input? are my injectors pooping out? Did I glaze over something in the tune?
Attached Files
File Type: msl 2018-06-14_16.43.51.msl (1.39 MB, 11 views)
File Type: msq 2018-06-14_17.07.18.msq (285.1 KB, 24 views)
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Old 06-15-2018, 02:18 AM   #2  
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I can't seem to be able to choose what I see in MegalogViewer. Nevertheless, it looks like you have way too much Acc Pump action. I'd like to verify with TPSDot, but cannot. Still it is obvious by looking at the TPS changes and the corresponding pulse widths that you are throwing a lot of Acc Pump.

You describe what is happening in your post... "acceleration triggers it". Well reduce acceleration enrichment.

2nd, your fuel map is a mess. You need to manually predict VE in areas that have not been tuned. If you can imagine running 140 kPa and move from 4500 to 5500 RPM, you are going to throw all kinds of extra fuel:

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Old 06-15-2018, 05:59 PM   #3  
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A solder point on a wire for my TPS had worn down and was barely touching. A lineman's splice and shrinkwrap has solved the problem
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Old 06-15-2018, 07:35 PM   #4  
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Alrighty then. Good deal.

Advice on VE table is still valid.
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