What plugs are you running and how much boost? What fuel? I had BR7's give me hell when they were gapped at .026 at 13-14 PSI while running meth. At that same gap they were fine on gasoline alone at 10ish lbs. Even just tightening them to .024 made a huge difference... no more loss of power.

Its not that my truck stopped pulling when I was blowing out the spark... but it felt like it instantly cut a couple hundred HP and felt soft.

I guess the real question is how lean, and what happens first. The sputter or the lean (chicken or the egg).

 

Fuel cell is in the bed with fuel pump below it. Should be vented well enough. FPR has fuel from the pump in one side. Out the other side, there is a single -10an line going into a y block to two -8an lines, one goes to each rail. There is a single -6an line out of the bottom of the FPR for a return line.

No, I'd actually be a little embarrassed to post my tune. I took someone else's tune that was way fat and started leaning it out, trying to get the wideband to read somewhere in the 7.5-7.8 range (I'm on E85). I got close to this afr, but it still goes lean sometimes. It's random, sometimes it will make a good pull all the way to redline, keeping a consistent 7.8-ish afr, sometimes it will start coughing and stuttering.

 

Yes, both banks go lean. I used the TunedByFrost conversion harness for my 80e swap.

 

By going lean, I mean 12+ on an E85 scale. As far as what happens first, I couldn't tell ya. Seems like its simultaneous. Plugs are the AC Delco version of the br7ef, gapped at .020". 15psi boost.

 

You have your FPR plumbed incorrectly. It needs to be after the rails (feed rails directly from pump first). This is probably causing the fluctuating in fueling.

 

One more thing, when I installed the cam initially, I had my head in my *** and installed it one tooth retarded. With an On3 76mm turbo, it ran fine, just took forever to spool and didn't make the power numbers the tuner thought it should make for 15psi. After I put the cam timing dot to dot and changed to the Precision turbo, it never would make a good clean pull with a safe afr. The guy that initially tuned it said he had to lean it out wayyy too much to be safe just to get it to make a full pull.

 

If the regulator was restricting flow with the way you have it plumbed, it would show on the fuel pressure gauge. You sure it is staying rock solid during your pull?

 

Fuel pressure rises 1:1 with boost every time. It does not fall off at any point, until I let off the throttle.

 

Can you program your wideband to tell it that you are running e85, or are you using lambda?

If you are using a gas scale, then you are way way too rich, but I dont know of any wideband that reads that low...

 

Yes, the WB is calibrated for use with alcohol. Has three settings. E85, E98, and Methanol. It is FAST part number 170590, but I added a second sensor to it.