Does kpro and your wideband show the same values?

 

yes. wideband is wired directly into kpro and then displayed through gague art. the values all match

 

yes. wideband is wired directly into kpro and then displayed through gague art. the values all match
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What are your spark plugs gapped at? Have you inspected them to make sure they are intact?

 

400lph fuel pump in a surge tank. Stock feed/return lines. Radium fuel rail and AEM FPR set at 40PSI with idle vacuum.
Dead times are ID spec if I remember correctly, will have to look at my .cal, cc size is 1000cc (this I had to play with. set it for 880 at first to get AFR's right, and slowly increased the CC to 1000 while I adjusted fuel tables).

yes. wideband is wired directly into kpro and then displayed through gague art. the values all match
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12.9 is pretty low for a idle AFR. Are you sure the wideband is correct? have you tried another wideband, or compared it to a dyno's tail pipe sniffer?

 

yes. wideband is wired directly into kpro and then displayed through gague art. the values all match
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What are your spark plugs gapped at? Have you inspected them to make sure they are intact?
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I am ruling out any other factors except ECU tune. I had the AEM infinity in there previously and everything ran absolutely perfectly, swap kpro4 backin and that's where the idle gets shitty. AFRs under WOT are spot on what my tuner said he set them on the dyno with tail pipe sniffer.

I also bought a second Kpro4 unit to rule out the possibility of a bad ecu/kpro.

I use NGK 2668 plugs and leave the gap on them that they come with. I change out plugs every 5k miles and they always look pretty newish.

 

There is one odd thing that I havn't investigated. The stock narrowband doesn't work at all, it will throw a code that the secondary o2 sensor heater/reading isn't working so we have that disabled. Seems the ground wire is completely missing from the C connector, but we have it all disabled in kpro. I wonder if that aspect missing is what's causing it to act up>?

I don't have any crimper and pinning tools to reinsert it so I cant rule that out just yet... I don't want to spend the money just yet but at the same time don't wana pay a shop 200-300 to repin 1 wire.

 

When you try using the stock narrowband do you choose: Narrowband (Secondary oxygen sensor)-PRA?
Also enable the secondary sensor.

 

Yes, they instruct to check used secondary as primary. Kpro only uses the secondary narrowband unless you wire a wideband into kpro4. Im told the narrow band is obsolete and not needed for anything now but im just trying to rule out why the misfire is there. Ive also been informed that the slight misfire at idle is nothing to worry about but im just so AR with these things...

 

I have both the stock and an aftermarket wideband installed but it seems the stock one actually works better at regulating the AFR at around 14.7
There's only small differences but might be worth getting yours to work just to have another reference.

 

What is the stock narrowband reading for an AFR? If I recall correctly, "using secondary as primary" has to be checked, but the secondary has to be disabled. the ECU doesn't actually use the secondary o2 for the AFR, it's just the way the programming is setup.
I keep my car in closed loop, and let my fuel tables / compensation tables do their work, so neither of my o2 sensors control AFRs, that being said, at idle both my MTX-L and OEM sensor read within 0.1 of each other, and I target 15.0.
Something to note: you cannot have both the OEM o2 sensor and the aftermarket wideband setup to run AFRs together. I also had a lot of issues trying to get both an AEM UEGO and the MTX-L to control in open loop, so I abandoned doing this.