My 99 Cobra with a Vortech non-intercool blower runs lean between 14.5-18.5 before the engine becomes fully warm for the first 3-4 miles..is this normal? Is the tune not good? :shrug:
Running lean before engine is warmed-up
- Thread starter svtleen
- Start date
At WOT its between 10.8-11.4. I just started feeling this leaning out more recently (engine cold) and was just wondering if it was a precursor to something bad.
from your wot a/f seems like it could be leaned out a bit but should be richer on cold start up than it being warm but it looks normal you shouldnt be worried
Your A/F ratio really only matters when under WOT. The gauge will be changing constantly when your are just driving normal.
As of the cold engine, maybe the ecu/tune has the closed loop mode on when its below a certain temp with some low timing numbers or something.
As of the cold engine, maybe the ecu/tune has the closed loop mode on when its below a certain temp with some low timing numbers or something.
Thanks for the feedback fellows.
LS1PUSSOUT
Banned
mine runs real rich until ive been driving for a minute. its in the tune for sure because it didnt happen with my previous tune
Yes, normal. You need to let car warm for 140 seconds before driving.
why 140 seconds and not 147 :shrug:.,., I mean why so specific .,., not being a smart ass
that is the time setting in the sct software for warm up. 140 seconds. Seems to work in all climates so i never have a need to change it. Please do not dukes of hazard your cars.
Hm... your startup open-loop table should be running rich, so the fact that it's lean is a bit unsettling.
I would start by looking at your MAF transfer function. Your car is in open loop for the first few minutes, and if it is set too lean then your car will run lean until it goes into closed loop and the STFTs can correct it.
Does the leaning out happen all the time, or just on tip-in? If It's just on tip-in then you can lower the PCM's idea of your intake manifold volume to compensate for it.
If it's all the time, I would probably be careful driving around too much. Even at part throttle, 18:1 is pretty lean, and although it may not cause damage, it certainly can't be good for the motor.
So, I would make sure your MAF transfer function is correct first, then go from there.
I would start by looking at your MAF transfer function. Your car is in open loop for the first few minutes, and if it is set too lean then your car will run lean until it goes into closed loop and the STFTs can correct it.
Does the leaning out happen all the time, or just on tip-in? If It's just on tip-in then you can lower the PCM's idea of your intake manifold volume to compensate for it.
If it's all the time, I would probably be careful driving around too much. Even at part throttle, 18:1 is pretty lean, and although it may not cause damage, it certainly can't be good for the motor.
So, I would make sure your MAF transfer function is correct first, then go from there.
Definately in the tune. Could be in startup fueling because there is a table in sct that relates to time since startup for fueling. That could need a little tweaking. Definately wait until the startup cycle is over to run wot.
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