TOO LEAN

Hi guys,

I have my Nissan patrol tb48 single turbo fully built engine and has motec m150 ecu and dash c125, I didn't tune the car it was tuned by my tuner before I started learning m1 tuning software.

my issue is on drag strip when I go wot in 1st and shift to 2nd at some point a message comes on the dash showing "too lean" and then it goes into a sort of limp mode it has ls3 electronic throttle and pedal the car shuts of the throttle and wont go beyond 3000rpm I checked in the tune there is throttle max position if it goes into limp mode I tried increasing this parameter with no luck. I am sure its not going lean the car was tuned on dyno and made 1100whp and fuel was on point.

Hi z.jarrah,

What you need to do is datalog the run and see what the AFR's are actually doing, just because it was tuned on the dyno doesn't mean that the transient conditions such as gear shifting are taken care of, this could be where your problem lies.

record a run and post up the datalog and a copy of the file and I'm sure one of the MoTeC users on the forum will be able to help

The message on your dash may or may not be related to what is actually going on in the M1 ECU. The dash takes data from the M1 but then it's possible to define a set of alarm conditions inside the dash that are completely independent of any functionality inside the ECU.

While there is the ability for the M1 ECU to introduce a limit as an engine protection strategy when a lean condition is encountered, what you're explaining sounds more like it is related to a fault with the dbw throttle system. This is particularly likely if it occurs directly after a gear shift that requires the throttle to be rapidly closed and opened. I'd start by having a look at the Throttle Servo Bank 1 diagnostics in your logging. If that is reporting a tracking fault or a sensor then this will cause the dbw throttle to be disbaled and will bring in an engine speed limit defined by the Throttle Servo Fault Engine Speed Limit.