Cold Start swings lean after 30 secs

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
tufgriz
Posts: 22
Joined: 2022 Jan 10, 21:51
Location: Culbertson Mt
Vehicle Information: 1993 4.0 Ranger xl Currently stock RAT1
1989 mustang gt running Megasquirt HCI 302 swapped back to a9l

Cold Start swings lean after 30 secs

Unread post by tufgriz »

A9L2 so, I dont have my wideband connected to the ecu yet (spartan WB) need to take a min and do the voltages. Anyways from a cold start car runs fine, after about 20 to 30 secs my wideband shows it start swinging lean all the way to around 19.5. it hangs out there for about 30s and then slowly swings back to 14.8-15.2 as it warms up. Would that be startup enrichment? or cold idle enrichment? from a warm 180 degree restart there is no swinging AFR's
decipha
Posts: 6297
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'25 F-150 5L

Re: Cold Start swings lean after 30 secs

Unread post by decipha »

thats perfectly normal and exactly what its supposed to do

its neither, you need to dial in your fuel
tufgriz
Posts: 22
Joined: 2022 Jan 10, 21:51
Location: Culbertson Mt
Vehicle Information: 1993 4.0 Ranger xl Currently stock RAT1
1989 mustang gt running Megasquirt HCI 302 swapped back to a9l

Re: Cold Start swings lean after 30 secs

Unread post by tufgriz »

ok, bear with me for a min. on base fuel tables all I can find are at .75 load and above. what table or tables for lower load? what about afr at lower load? Thank you
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