Thread: Running extremely lean?

Finally got my fwd sr running and brought it to the track last Saturday! Sr16ve n1 .20 pistons fully ported and polished 5 angle valve job with jwt s5 cams stock sentra ser ecu. Ran for three laps before it shut down completely though I wasted the motor so I rushed it home and did a compression test it was completely fine! Stuck my camera down the bores they looked perfect. The plugs were hot white but not melted away. Question is what would cause this to happen? I have 60 psi of fuel pressure and the timing is on the money. Tps? Dirty maf? With my calculations the over bore pistons wouldn't even bring the liters above 2.1 so the fuel pump and injectors should be fine as well as the stock ecu tune.

stock ecu tune isnt tuned for 60psi fuel pressure, and neither is the stock fuel pump.

Well it's a stock pump and stock fpr gauge says 60...

Stock pressure should be 43.5psi. 58 psi is 4 bar, you should actually be running rich. At 4 bar, 270cc injectors will flow at 311cc. I would suggest buying a wideband A/F meter and see where you are at. Swap out the fuel pressure regulator with a new one or used good one. It also could be a clog in the fuel return line. My guess is, your fuel pump over heated and shutdown.

Stock fuel pump can be ran at 4 bar=58psi with no problems, for the most part.

Kinked fuel pipe imo.

What is the exact size of the feed and return lines? I ran 1/4 inch steel for the feed and 1/4 inch gm plastic line for the return. I had it setup with 1/4 gm plastic feed and return but it was lacking psi due to the small fittings(inside diameter) that are supplied with the kit. When I ran the steel line for the feed it seemed to help . Before I ran the steel line it was bogging badly as if it wasnt getting enough fuel. I am prob going to run a 3/8 feed with a 1/4 return I am sick of this! Worst part is I was so fast it wasnt funny I had the race won practically in the first two laps I was peddling the car sand bagging playing with the leader. So pissed off.

Also I removed my maf it was actually very clean! Does it matter how far I have the maf away from the throttle body as I ran the air box and maf inside the car to keep it cleaner than under the hood getting plastered with dirt from the track. I ran a heavy plastic flexible tube from the throttle body through the fire wall to the maf/air box the tube is prob around 18" long.

5/16 is the stock sizes

That is deff the problem then. Running 5/16 feed and return tomorrow then ill see if its any better.