3.8L Blown (Magnuson) Wrangler - Can't get it to idle
I have an '07 Wrangler, 3.8L, 6-speed that I can not get to idle without surging up and down, up and down. I installed a Magnuson supercharger that only boosts the engine by 3-4 pounds. I've set the VE Tables and the Jeep runs great, it just won't idle worth a damn. I have tried everything I can think of to stop the idle surging, but nothing works. I've tried everything from +/- timing at idle, fuel at idle (VE), Stoich throughout, raising the idle RPM, lowering the idle RPM, PID for both Spark and Torque.
The supercharger has a bypass which is functioning properly, so the only thing that's different from stock at idle are the injectors (Magnuson injectors). The Pulse Width has been modified by Magnuson in their delivered tune file, I have not messed with PW.
Stoich is working properly. Checked with an LC-2 wideband. Have tried from 14.1 (.0710) to 14.7 (.0688) stock. WOT results in 12.0 -12.5 AFR
I can tell something isn't happy at idle even though I'm reading 14.7 (have tried 14.1) because I get a 'stumble/miss'. When it stumbles, that's when the diving board (PID) starts. When it corrects, it might stabilize for a second, then it stumbles again, which starts the diving board again. Again, I've messed with the PID values and all that does is speed up or slow down the diving board affect.
This problem only occurs when the engine is totally hot (195-205F).
I've attached a log of the Jeep idling and the Tune.
Is anyone familiar with the 3.8..?
Any help is much appreciated. I've run out of ideas. I've been messing with this for 2 months.
What I did find is pulling timing at idle gets rid of the stumble. I'm at 10 degrees (was 27 degrees) at idle in "Part Throttle Base" table, which translates to the engine firing right at 0 degrees at idle (hot). The idle surge is still there if there's any kind of stumble, but it does recover faster as I also added some torque to the Throttle and Spark PID tables. I do get a pretty good surge on cold start when the engine is trying to idle down (from cold rpm to hot rpm). I'm told this is happening because of the extra manifold pressure the engine is ingesting from the supercharger....basically too much VE.