Lean to rich under decel
Hey guys thanks I’m new to the Forum and am looking for some advice regarding a lean to rich condition under deceleration.
- 600hp unit on my 383 stroker/ th400
so this is the first time putting some miles on my truck since the install and the truck runs pretty well with the exception of a few this. First, I’m getting a lean to rich condition under decel. Once I let off the throttle after moderate acceleration afr jumps to 20 and then jumps to 10 ( can feel noticeable hesitation) but once I apply throttle it clears up. Afr is 13.6 idle, 14.3 partial throttle crushing, 11.3 wot
second is when I start the truck initially the rpm’s hang for about 30seconds around 1500 then eventually settle down to a nice idle around 850. The rpm’s do the same thing when the transmission is shifted from drive into park(or neutral) the rpm rise for 30seconds to 1500 then settle down to a nice idle. TPS is at 0 when it does this.
cam setting 2
vacumm is 12 at idle
iac 10 at idle
engine temp is 185
no flat codes
Plug wires are pulled away from any fitech wires.
02 4in past collector and plenty of pipe after back to the muffler
in tank aeromotive pump 58psi fuel pressure at idle(gauge off fuel rail)
No adjustments have been made to the unit yet
map number don’t get stuck.
any pointers would be greatly appreciated!!
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1st - great looking truck. Your issue is certainly unique. My 1st guess would be a small air leak at the O2 sensor. Try checking / sealing with high-temp RTV. Beyond that I recommend sending a data-log to Fitech.
You mean in regards to the rising idol when I put it in park? The lean to Rich problem solved by turning the fuel cut off to 299degrees.
I agree with above. Disable decel fuel cutoff by setting enable temp to maximum.