Todd1225

1993 Lexus SC300 NA-T
V8 MAF
Boostlogic 525cc injectors
SAFC-2 (low throttle is 49, high throttle is 50)
Open Atmosphere BOV

Finished turboing this car last year, after getting the SAFC2 installed correctly the car was driveable but with a stalling problem. If you accelerate in any gear up to about 2500rpm or higher and then pop it into neutral the rpms will dip and then almost hit zero and struggle to stay running...sometimes it would die. At this time I was not taking out any fuel using the SAFC2 at this moment. I also had only one O2 sensor hooked up as well.

I also noticed during this time, that when I started the car, it would rev to 1500 to warm up, them plummet to almost cutting off, catch itself and then back to 1500, repeat...it would eventually stop and level off but the car would really spit and sputter if I tried to drive it. After about 45 seconds of driving awful it would run just fine.

Started dialing out about 30% fuel and still had the same problem with the car stalling when going to neutral from 2500rpm and up, same thing if I just pushed the clutch back in when doing 2500 rpm+. But I did notice that the dipping/revving problem when I started the car was gone.

Got the first o2 sensor tapped into the same line as the second o2 sensor (getting the same reading using a meter for both so I know they are both working), but third sensor after the "cat" is still unplugged. I understand this does not control the mixture but only makes sure the "cat" is working. I still have the stalling problem and oddly enough the dipping/revving issue at startup is back.

I dial out 40% fuel and the stalling problem is much better, the car will catch itself when the rpms drop and will not let the car die....but the revving/dipping problem when starting the car is back. Experimenting even more, I dial fuel back in at 800 and 1000 rpm and the car's starting problem goes away but this puts me back to stalling when going into neutral. Maybe if I dial out more fuel in the 1600-2000 rpm range I won't have to take out more fuel at 800 and 1000. So I lean out 1600-2000rpm points and richen the 800 and 1000 up to get a smooth start, but the stalling problem continues.



At this point it's either lean the car out to 40% at the 800 and 1000 rpm points and have a starting problem or dial out about 32% and have a smooth start but stalling when going into neutral. The 800 and 1000 rpm set points are the only adjustments that seem to effect the revving/dipping and the stalling problems, so when I correct the fuel it's for these two points.

In summary:

No fuel correction = stalling when going to neutral and revving/dipping starts, starting problem eventually went away.

40% fuel correction = revving/dipping starts but will not stall going into neutral.

32% fuel correction= smooth start but stalling going into neutral.

I don't wanna have to buy something else (unless it's cheap) to correct this, I've tightened down the BOV, got both sensors reading and have tried multiple SAFC settings and i either have one problem or the other.

Any suggestions?

Todd1225

Duplicate thread, can't seem to see how to delete it on the "edit" screen. Mods please delete.