Baja Rooster

iTrader: (1)

In what way? Fairly new to the market, right?

Bonzen

Update...lake tested again yesterday but still no success. Bypassed the vapor return system with the return plumbing but still no change. Plumbed in a low pressure boost pump into the fuel feed line before the stock fuel pump in an attempt to "force feed" the stock pump but even that didn't fix the issue. pressure still drops on the gauge and the AF gauge still shows lean jsut in the flat spot area. and then at WOT it runs great again...lol

Baja Rooster

iTrader: (1)

The fix is obvious - just leave her wot the whole time.

My sympathies. Gremlins have sent many boats to the crusher, lol. Best of luck!

Bonzen

Thats pretty much what I do...throttle is on or off! Only problem is the 50 gallons of gas in the tanks don't last too long that way!

ham_r_down01

iTrader: (1)

Just some curiosity. The map sensor is being used yes? I haven't been into fuel injection gremlins for a while. I remember camshafts messing with tbi. Is it possible that the combination of camshaft and intake design, that there is a resonance being created causing a lean spot?

Or do you think it's all pressure related.

Just curious.
Best of luck.

Bonzen

Yes the MAP sensor is brand new and being used. Kpa / MAP readings are good as veiwed on the laptop.

The camshaft I am running was verified by COMP to be computer friendly. If it wasn't I would expect other performance issues. I honestly thought for a while that there was some sort of resonance/manifold pressure or vacuum issue. But seeing the FPG drop in real time proves to me that fuel is being choked off before the throttle body or the regulator was malfunctioning allowing the pressure drop during that rpm range.

I have installed an Aeromotive 13301 in the return line and a fpr bypass kit where the stock tbi regulator used to live. So now I know I have a proven fpr. The fuel press gauge shows approx 32psi with key on/engine off. So everything seems normal. Reay like that you can adjust the aeromotive on the fly. I also put the fuel pump on a relay straight to the battery. So the ignition still turns it on and let's it prime like before but now its drawing power straight from the batteries as opposed to through the wire harness/ecu. So if there was some weird EMI or intermittent signals being sent to the pump during the flat spot in the powerband causing it to lose power that should be eliminated now. Also plumbed In brand new fuel feed hose Along with a K&N high flow fuel filter. Hoping these changes fix the problem! I dont know what else could cause a fuel pressure drop and lean reading on the AFT gauge!