Hay guys, have a question about my volt light. I have an 87 turbo T with 140,000 miles . Motor has about 6000. When I drive down the road every so often the volt light comes on, day or night. When the volt light is on I cant give it more than quarter throttle with out the motor back firing . The light will stay on for about 10 to 15 min, city or highway driving. The car has a new battery and a brand new Napa Gold life time warranty 120 amp alternator. My guess is the cam sensor. Its like the cam sensor isn’t getting the right amount of power to deal with the timing. The car also back fires a little if your driving about 55 mph and you floor it and it down shifts to 2 nd gear. It does this with out the volt light on. Other than that it is the motor runs fine. If you start form a dead stop and floor it it runs great. (12.5 ¼ time) The car got almost all new sensors when redone but the cam sensor I did not replace. I think it is the original one. Please help!!!
I don't think the cam sensor has anything to do with timing. From my understanding, the cam sensor is used to get the injectors firing at the correct time compared to the spark signal that comes from the crank sensor. How old is the module/coil? Do you have a scantool to try? I'd pull the alternator back off and have it tested, just because it's new doesn't mean it's good. I'd also check all of my connections, maybe you've got a wire grounding out some where or a loose ground wire. Maybe somebody else with more electrical knowledge will pipe in here.
My guess would be the alternator, if it was the cam sensor that wouldnt throw the volt light on? Could be alt crapping out on you causing your loss of power.
In reference to Scott's comment, the cam sensor could have been used to detect whether the engine was on compression or exhaust, but to avoid having to do that, they had each coil fire the two cylinders that are on compression and exhaust at the same time. The idea may have been that if you fire the plug while the exhaust valve is opening, you might burn some unburned gases from the compression stroke. It might also have been that they were saving money by not having a separate coil for each cylinder. Regardless the motivation, todays GM engines have a coil for each cylinder.
As I understand it, the cam sensor timing is not critical, because, when based a horsepower result, you can hardly tell the difference between SFI (Sequential Fuel Injection)and bank to bank fire. SFI probably improves emissions a bit. Any experts know for sure?
Scott in regards to your comment about the coils and the module. As far as I know they are original. They both still have the original stickers on them. If you guys are saying it has nothing to do with the cam sensor, then what would be making the volt light come and make the motor back fire like crazy when you step on the gas. I don’t think a bad alternator would make the motor back fire and miss. Could it be the coils or module going bad and they are making the volt light come on, and the motor miss?