SD2 crank fuel trim


Dec 4, 2013
My cars on e85 and 120s. Its very hard to start when cold ( and its still in the 80s here). I moved my crank fuel trim in sd2 to 15.0 and still cranks for a long time. Should I just keep increasing this until it starts better? How high can this be adjusted? Once eng warm it starts almost instantly. Is this value a % increase? I skimmed over that long 40 page sd2 post a few times already.
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presuming your fuel pump(s) prime and hold properly, then this factor is applied like a BLM to the crank fueling.

IAC / TPS stuff affects this. Crack open the throttle on the next cold start or 2 and see if that helps some. Then post back.

20 or 30% (or even more) crank fuel trim is not uncommon.

going from 0 to 15% you probably saw at least some improvement?
When the car is cold, you want it to crank a little before it starts. This gives the oil pump more priming time before the engine fires at 12-1500 rpm and having no oil pressure for a few seconds. Thats my thoughts for the SD2 crank fuel trim.
It was cranking for too long. Had to crank then let off starter and crank more. I ended up changing crank fuel trim to 30 and it started good cold. Better than it use to start on old 6.1 chip and 80s. Thanks for replies, Im sure I will have many more questions. Hope to get time to get out on the road tuning next week sometime. Want to get it dialed and try to make our last track night in December and see if it can beat my PB.
I put -12 in the cranking fuel and fires up every time with E85