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AEM 2 Rev Issue

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I tuned car RB26DETT with AEM 2. my issue when I rev the engine it always goes lean "18 AFR" and I don't know what to do to solve this issue.

I made it in vacuum 13 AFR and full boost 11 AFR but when I rev the engine first rev it goes 18 AFR. maybe the problem with throttle sensor? or I need to increase the fuel per throttle points? which will affect my tune.


Are you tuning solely off MAP vs RPM or are you using a 4D overlay/correction with TP as well?

Tuning an RB26DETT requires 4D Mapping or a form of AFR correction overlay which could be the issue (Although without seeing the map or the exact conditions on when the issues occurs I am only guessing from experience).

Allow me to explain, as I am sure you're well aware the RB26 runs individual throttle bodies, from a tuning perspective what this means is you need to map your fuel table based off TP, MAP and RPM.

By your comment I am assuming you're tuning of MAP vs RPM, running 13 AFR in Vacuum and 11 in boost. The issue here is that, because of the characteristics of this engine setup MAP alone isn't a good representation of load/air flow.

One example where this can cause an issue, it is possible to be at 4000rpm 40% TP and 12psi (Target boost) on your fuel table will sitting in the zone 4000rpm x 180kpa (Absolute) tuned to 11 AFR. Now increase your TP to 100%, you will still be at 4000rpm and 180kpa however your air flow has now increased, causing the AFR to go lean.

Do you have a map which you can attach?

Any other information regarding this issue, i.e has it always done it since tuning? Is it consistent and a repeatable issue? Is there something in particular which makes it worse?

Thank you Chris for your reply.

Please find my fuel table. I switch off the TP base map and I am using the speed density (Engine Load) vs RPM.

I increase the fuel in area 500-2200 RPM in -0.06 - 30 psi to resolve this issue but still it's the same.

Attached Files

I guess a pertinent question would be, are you still running the stock ITBS and manifold, or are you running an upgraded pod style plenum ?

if you're still running the stock ITB intake then you need to use the TPS as your base map with a compensation for the boost. Andre done a webinar on this and it now buried deep in the archive, here it is and it explains how and why you need to tune this way:


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