EFIDynoTuning Forum

Can anyone look at this log and see if they can figure out what is going on with this car? 89 SSP running Decipha base A9L tune and strategy. 302 gt40p, 24lb, 24lb bbk MAF, edelbrock intake, 5 speed. Car runs great sometimes and then the computer wigs out and fueling goes crazy. Sometimes you can just blip the throttle and fueling correction will jump back to around 1 and it will start running great again, other times you have to shut it off and restart it. Attached data is from a startup after a 15 minute trouble free drive. Weirdness starts at about 70 seconds in. This car does not have a wideband in it.

its dropping in to closed loop too quickly while the hegos are still cold so the hegos are throwing fuel around

set the opclt CL delays so it takes 250 sec when cold, 200 when warm and 160 when hot.

for good measure you can set the min switches scalar to 8 so the hegos switch 8 times and are functioning before it goes in to closed loop as well

Cool I think that took care of it doing it while switching from open to cold loop. Can you look at this one starting at 6 minutes until about 7 min 30 secs. It was warmed up and sat for a bit, started back up and idled all the way to running temp. Started reversing down the drive at around 6:15-6:30. HEGO goes way lean and correction goes wild. I blip the throttle a few times and then correction goes back to around 1 and runs 100% normal again. Drove down the road just fine after this.

the hego breakpoint is too low

just go ahead and set it to .4 and should be good