have spark and fuel, still won't start??

[noname7198]

We've got a track only s13 coupe with a redtop sr installed. No chassis harness, just an engine harness.

Build thread here:
http://www.zilvia.net/f/showthread.p...ht=coupe+track

We have spark and fuel. When we push the start button the motor turns, but sounds like it doesn't have enough power (like a dying battery). The battery is fully charged. We also tried a new battery, but still it barely turns. The battery is in the trunk, running 4 gauge wire straight to the starter. The starter has been tested and is working. We have a seperate switch wired to power the ecu and everything else that gets 12v power. We get ecu codes 12 (maf) 13 (coolant temp sensor) and 34 (knock sensor) but none of those should prevent the car from starting.

We are out of idea's. Can anyone think of anything else that could be preventing the car from starting?