So I just finished my supercharger build and uploaded my tune (tuned by trifecta). I'm running really lean especially when coasting (have a wideband hooked up with my interceptor and it maxes out at 19.8 when coasting) but also runs lean under throttle. I also am getting random spouts of misfires and I can't boost past 4-6 psi. When it hits that level it starts to stutter and the boost needle bounces and it almost sounds like a rev limiter. The running lean is the biggest issue though and it even stalls out when I come to a stop. I am gonna data log for Vince in the morning but I'm kinda paranoid so I wanted to post this up and see if anyone has had similar issues or knows if something other than the tune might be wrong. Any help would be greatly appreciated!
Thanks,
Garrett

 

dont push it to much you can blow the engine since your lean

 

oh the good ol dying when coming to a stop on LS SC builds lol.very common on most of our builds.Some get lucky.

 

Yeah I was scared to death test driving because of how lean it was. It richened up when I gave it some gas (naturally) but I still didn't push hard. Didn't take much to hit those boost numbers and notice it wouldn't go higher though. I kinda expected the lean a/f ratio on the first tune but not so much the misfires and limited boost

 

usually Vince sends us a dud tune thats rich idk why your runnin lean

 

The 19.8 while coasting is normal. It's part of emmissions. Turns off fuel injectors aabove a certin speed/rpm lets the momentem of the vehical keep the engine turning.

 

I never had misfires but I did have the rpm fluctuation to a stall for my first couple of tunes from Vince.

 

I had heard something like that before but it just had me a little worried. It's still running kinda lean regardless but good to know that's normal.

I'm running autolite xp colder plugs and i've heard they don't always run well in gm vehicles. Anyone know if those plugs could be causing the misfires?

And also does anyone know why my boost is limited?

 

While coasting and still not a Decel that is very abnormal. And very unsafe. Now on a Decel you have what's called decel fuel cut off which means your not pushing fuel into the.combustion chambers. So thatll make it lean but on coasting that's bad.

 

Do you just mean decelerating when you say decel because my car is always decelerating when coasting because its a 5 speed and the gears start slowing me down.

 

Decel meaning Ure not at all on the gas u just let isn't Decel by being in gear and letting off gas. So yes. Which is bad for the transfer of power clutch to tranny. Use the brakes. A lot easier to change

 

Yeah I wasn't saying I use the gears to slow myself down I just meant that anytime I'm in gear and let off the gas I start decelerating, not that I downshift to slow down. So would it be normal for it to run lean anytime i'm in gear and let off the gas?

 

If u let off gas in gear is called dfco which will enable lean occasion .

 

sounds like ur power enrichment might be off or set incorrectly. that could be ur problem for the stuttering when in boost

 

^^^^ Zep, good catch there sir. And tune can be off as well

 

Hopefully its something like that that can be solved through the tune. No one knows what may be causing the misfires?

 

misfires all the time or just at idle?

 

Both. More at idle than anything but its just random. Misfires a little then stops then itll start again a few seconds later. It's kinda hard to even notice by ear but my interceptor monitors misfires

 

yeah mine does the same but only at idle and Vince can't figure it out.So that's the main reason why I'm switching to HPT.Try switching plugs,check vacuum leaks/boost leaks.

 

Put brand new plugs in during the build so shouldn't be those but I guess you never know. I don't hear any vacuum leaks and can't boost well enough to tell if theres boost leaks lol

 

you won't always hear vacuum leaks.I had many without hearing them.and try putting the delco's back in just to see if the autolites are casing problems.you never know

 

I tuned a tvs hhr that had this issue and I put my tune on and bam isles fine. So the only thing I can think of is injector offsets are off .

 

The hhr was trifecta tuned. I made the base file for the car and it ran amazing on that alone. But I tuned it and its good. But is say its his injector scaling.

 

im glad you said that cause my idle misfires have me stumped and the tune is the only thing I can think of.

 

I'm hoping all this stuff can be resolved with an updated tune. Also don't know if i mentioned it but if I blip the throttle when I'm sitting idling the rpms start bouncing between 500-1200 rpms and the a/f ratio bounces up and down too like its having trouble adjusting itself for the quick throttle change