SCT cold/hot start tuning


Mar 2, 2003
now that its winter, when my car starts is past 10:1 AFR really rich.

Was wondering where i can change this and what is a good target AFR when starting cold. even how long to have it in cold mode.

When I start the car hot, the car goes lean 16:1, 17:1 then the O2's start kicking it up to 14.7 but it sounds like **** untill it gets past that loop.
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If the MAF transfer function is right on - then adjust the cold start fuel table in temp areas your are experiencing - ratio the current lamba by the lambda liusted in the table so you are at 12:1 or thereabouts for a cold start. E.G. if it's 20* out - look at the lambda values in the table for -30 through 30* at 'idle' load values usually 15-20%. Just eyeballing it it looks like all the values average out to about 0.80 lambda or an AFR of 11.7 or so. If it's actually 10.0, you know you have to make it leaner, so take 11.7/10 = 1.17 and multiply 1.17 by all the values in the lower load lower temps. You can also increase the cold start decay to keep it there sooner - and add a startup idle adder and lengthen the time it is in force.
cool, i know i took a peek in there before. dont think i changed anything in there. How would i know if the maf function is on? You did the base tune, so i assume its on.
Check AFR vs. MAF volts at all the free rev areas and on the road - force OL to do this. Should be 14.64 or thereabouts. If not you need to adjust. The base files usually are close, but do need some work. I think you got my video, just look at the EEC IV chapter - it'll show you step by step how to tune it.