Rebuilt motor. Installed new map and coolant sensor. Set timing to 15 w coolant sensor unplugged. Running a msd 6 with blaster coil. New fpr. Running fuel cell w factory 5/16 in and 1/4 return lines. Walbro 190 external pump.
Everything sounds good and runs OK. Took it to dyno to do some fine tuning with plenum and throttle body.
Dyno guy does first pull and says instantly something is wrong. In 3rd gear, car hits 4300 rpm and instantly drops from 110hp to 70ish and barely climbs. Graph is a bit wavy, we both expect a much smoother gain and certainly not this drop off. After changing plugs, wires and spare ss coil, with no change over a few more pulls, we advance timing to 20 just to see what happens. Car gains 20 HP but still drops off. I then watch timing light during pull. At point of drop off, timing retards to 5... No wonder it looses HP. Tested tps sensor and it goes from 0 to 5 volts as does map sensor. Narrow band o2 bouncing as it should. Wide band showing 12.0 Afr. These motors have no knock sensor. What could be causing it to retard so bad? Msd box? Bad distributor? Ecu going bad? Timing marks are all lined up OK. Next thought was to change distributor. If not that, go back to stock ignition and coil. Other thoughts/ideas??
