# RB25 issue **URL:** \ **Category:** SON240sx Automotive\ **Created:** [May 28, 2010, 12:01pm UTC](https://forums.speedlife.net/t/rb25-issue/155718 "2010-05-28T12:01:14Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![coldshot888](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@coldshot888](https://forums.speedlife.net/u/coldshot888)\ **Post date:** [May 28, 2010, 12:01pm UTC](https://forums.speedlife.net/t/rb25-issue/155718/1 "2010-05-28T12:01:14Z")
s14 with rb25 conversion, the car runs ok but when u mat it in 1st or 2nd it falls on its face intil it gets to high rpm… i checked my MAF and cleaned it , didnt change anything i cant find any leaks in the plumbing, u can smell gas like its running rich… i dont know how to program the apexi air fuel ratio module on the dash, anyone know where i can get help? im in st catharines area, thx ---
**Author:** ![Feint](https://avatars.discourse-cdn.com/v4/letter/f/71e660/32.png) [@Feint](https://forums.speedlife.net/u/Feint)\ **Post date:** [May 28, 2010, 3:45pm UTC](https://forums.speedlife.net/t/rb25-issue/155718/2 "2010-05-28T15:45:47Z")
A forum called GTRCanada :p. How are you monitoring / changing a/f ratio’s? Is this an SAFC, or just a turbo timer with a/f and o2 voltage features? 450 on the o2 is 14.6, which is pretty much stoich. Does this only happen when floored in 1st and 2nd, and not 3rd, 4th, or 5th? Does it only fall flats on it’s face when you floor it and is perfectly fine any other time? Be more descriptive. Also any time you drop the hammer on the rb25 it dumps fuel, it will smell, and it will pop/shoot flames. It is rich in higher rpm’s from the factory. ---
**Author:** ![coldshot888](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@coldshot888](https://forums.speedlife.net/u/coldshot888)\ **Post date:** [May 28, 2010, 10:00pm UTC](https://forums.speedlife.net/t/rb25-issue/155718/3 "2010-05-28T22:00:42Z")
well basically if u baby it in 1st and 2nd without boost it will drive decent, when u start to make any boost it just boggs down… i have a apexi safc ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex034/uploads/speedlife/original/2X/b/b7170c8eddc0b95ece6b88172b2f416a08489a45.png) [@system](https://forums.speedlife.net/u/system)\ **Post date:** [May 29, 2010, 5:46am UTC](https://forums.speedlife.net/t/rb25-issue/155718/4 "2010-05-29T05:46:45Z")
check on gtrcanada they will have a better understanding of what u are describing, also google the apexi safc and you should be albe to find a basic map to the safc to get you pointed in the right direction, but i would reccomend having the safc properly tuned if you dont know %100 what u are doing with it. somebody like dan (u2unedyno) will be able to help you out for that farmer ---
**Author:** ![87s15lt1](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/87s15lt1/32/5706_2.png) [@87s15lt1](https://forums.speedlife.net/u/87s15lt1)\ **Post date:** [May 29, 2010, 11:58am UTC](https://forums.speedlife.net/t/rb25-issue/155718/5 "2010-05-29T11:58:09Z")
boost leak test. start with that for sure. sounds like you have a cracked/ripped/torn coupler. when it’s boosting it leaks.