AFR correction changes with Ethanol %

M

mtocrs1

Member
Hello,
I had my SD2 setup on gas pretty good for idle and light boost. Decided to make the switch to E85 before wide open blasts. I ran the tank almost dry, turned on E85 in SD2 and put in 5 gallons of E85. The sensor went from 8% to 48% ethanol content shown in the powerlogger software. The car stumbled a bit on start up and then cleared up. It runs fine but my AFR correction is now around 20%. Adjusting the ETH-C table doesn’t make a difference. I expected the AFR correction to remain roughly the same. I can adjust idle fuel to compensate but that defeats the purpose of the sensor. What am I missing?
 
M

mtocrs1

Member
Hi Eric,
Yes I have flex fuel turned on, actually the next day it fixed itself.... I do have something else now. I have idle fuel good and where I like it using parameters 1 & 2. Idleis good both at cold start, warm up and idle. The problem is on hot start before entering closed loop. During the warm start before entering closed loop the idle AFR is to lean and runs rough.
Before closed loop is enabled is idle fuel only controlled by the VE table. Is adjusting the VE table the only way to correct this?
 
EricM

EricM

Administrator
Staff member
You must have some injector heat soak. What injectors? What AFR are you targeting at idle normally, and is correction close to zero at idle?
There are some ways around it, but worst case I'll need to tweak something in the chip.
 
M

mtocrs1

Member
Injectors are new 120s. I am targeting 13.0 idle AFR. My last log showed AFR correction hot idle ranging from 9-11.
I honestly thought it was more around 4-6 but logs dont lie. I guess I should try and get the AFR correction at idle closer to zero and see if that helps. If you think otherwise let me know.
 
EricM

EricM

Administrator
Staff member
You can try to shoot for minus 5 or so on correction, so it will be a tad richer on the restart.
 
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