Dlopez31

I have a 94 z28 with a rebuilt motor with less than 2000 miles... the car has an lt4 hot cam bored .30 over and 1.6 roller rockers. i also have a csr electric water pump, msd 6a ignition box, and long tubs wit a cat back borla exhaust, when i start the car the service engine light is not on and the car runs like a monster.. then after 15 minutes of driving i get a back fire and the service engine light comes on and the car feels like the cars timing does not advance like it is supposed to. when i check the codes with my lab top i get a code 36 Hi-RES Failure...... i have been doing some research and found that the problem mostly comes from the opti spark but the opti spark that i have on it is fairly new. i had gotten it about 6 to 7 months ago..... i just want to make sure that it is not anything else before i have to buy another opti spark and take off my water pump.... so if you know of anything else that i should replace or check first please let me know.

Nostang

iTrader: (4)

It will most likely be the optical sensor in the opti or a wiring issue to the sensor. Check the opti plug for corrosion before pulling it apart. You can also check to make sure the wires have good continuity to the pcm with a voltmeter but I have a feeling it is the optical sensor.