Pontiac Repair: 05 sunfire ignition system, crank sensor, engine computer

Question
vehicle cranks, but has no spark. have 12v at ign. module

Answer
Hi Bruce:

do you have ground there as well? I'll assume you have no spark on all 4 cylinders? this system is a bit complex and with out the aid of a true scan tool your sort of out of luck. the crank position sensor sends a a/c volatge signal to the engine computer and the engine computer will then send the coil control message to the Ignition module. If you have no spark on any of the cylinders it can be a module/computer/crank sensor or a wiring issue. if you had a scan tool you could see on the data list engine speed while cranking the engine over at least you would know if you are indeed getting an rpm signal to the computer. without that your out of luck that is one of the very first checks in the trouble tree to fix a cranks but no start no spark. One last though does this have injector pulse? Are the spark plugs wet from gas and you cranking it? if the plugs are wet then your getting injetor pulse and that would mean that the engine computer sees the rpm input and that would narrow down the possable causes of this. good luck :-)