VersaTune User Forum

Its been a while, still having the same issue at wot in third and fourth gears.

Here is the last log I did.

AFR at WOT is reading 16.18 at 347.031seconds in the log!!! If that is accurate, that is really bad. I see a fuel cut at 349.092 seconds.
This tune is not right.

let me do another log. I remember I fixed a exhaust leak before the primary O2 sensor.

That would explain the crazy AFRs.

Here is my latest log. I did the log in 4th gear, started at 3 k until it cut out.

You are most likely exceeding the overboost protection fuel cut limit.

Indeed, and the AFRs are still on the lean side. There's a chance that the primary O2 sensor doesn't want to fully collaborate any more. Everything else look.. I could say normal considering....

I believe the tune is not heading the right path.

too lean (maybe calibration of no leaks)
high boost not utilized by appropriate timing.

you have a 3.5" maf housing - I would expect that at 4V maf you should have more air , maybe 20-30 g/s more - that could explain the lean mixture. you may check my logs in the next thread - these are also on 3.5" maf housing (still not perfect) so I would expect to see readings more similar to mine in the maf voltage-mass.
As I saw your mods do not include forged piston/rods , these logs with 23psi , lean mixture wont let you drive for long.

without forged internals (if you truly not have) I would try to keep boost lower and play with ignition timing (which will also raise combustion pressure , but at least will give you lower boost air temp, better response and better use of the air you are pushing)

His MAF Cal is fine, or at least is close (looks like a Statified aluminium 3.5" JBR intake maf cal). His AFR readings though are totally shot.