timing or fuel system problem?

[TDS]

I am unsure what is affecting my car. i recently swapped in a rebuilt ka24e and am currently having a few issues and i am unsure what to make of them. First of all i have a check engine light. At first it would come on and off, now its just on. I ran diagnosis mode on the ecu and the only thing wrong was that the car was running lean. engine is stock except a lightweight crank pulley i installed. Sometimes engine will not start immediately at first crank (takes a while) or if i crank it twice it turns on. I also noticed that the last time i filled up the tank completely, the fuel gauge stayed right below F(ull). On my old motor, i added gas till it was completely full and the indicator would go above F(ull). Also during the first week after the install, it seemed i was geating very good mpg with almost 200mi on half a tank. When the low fuel light came on, i added a full tank of gas, and now with less than 1/4 left, im bearly reaching 200miles!!! 275mi~ on a fuel tank of gas was the avg on my old motor but you could smell the emissions (gross polluter), and this is not the case with the rebuilt motor. Also idle is perfect at 750rpm. So what could it be? Is there something wrong with my fuel system that is making my engine not get enough gas, while at the same time giving me improper reading of my fuel? Thanks for help. btw it was my first engine install (excuse the newb)

[S13 240SX]

its fuel, check your injectors, as for the improper reading of fuel, could be the fuel pump, there's a sending unit built with the pump, that could be causing your improper reading, or your gas gauge is just screwed up.

And if you plan to turbo this rebuild ka24e get it to stop running lean first.

and also how is running an ECU check gonna say your engine is lean, it'll only flashs out codes, and the only type of code that could mean a fuel problem would mean code 45 and which 45 stands for injection leak.

[TDS]

well according to the chiltons book for the 1989-1992 240sx and other nissan cars, all cars have 5 modes of diagnostic except the stanza. mode 3 throws out the 2 digit codes, I got 55 (nothing wrong) but one of the modes (2?) checks for lean or rich (i got a full lit green light-meaning lean).

[S13 240SX]

oh wow your lucky than, My ECU wont go into that mode, I can' only get mode 3 where it throws out codes.

[xsblacksx]

yeah i forgot i can do that!

[xsblacksx]

check o2 sensor

[straightedge]

double check your ignition timing. cam timing could be off as well.

[KATwo40]

My vote goes to twin problems.

Problem 1: O2 sensor crappin' out on ya' (probably reading lean, then the ECU is trying to correct by running rich, thus wasting fuel).

Problem 2: Fuel sending unit crappin' out on ya' causing the fuel gauge error.