thejim42 Posted August 18, 2016 Share Posted August 18, 2016 I just picked up am 87 4cyl 5 speed and it has no spark. Ive tried replacing the coil, the icm, the cps, and the ecu. I still have no spark. Anyone have and ideas? Link to comment Share on other sites More sharing options...
Marine1Texas Posted August 18, 2016 Share Posted August 18, 2016 It may not need parts but need to check the wiring. I don't know if the 4cyl is got the ground issues like the 4.0 does. I am sure some owners of the 4cyl will chime in. Link to comment Share on other sites More sharing options...
thejim42 Posted December 15, 2016 Author Share Posted December 15, 2016 what tells the computer to send voltage to the coil for spark? Link to comment Share on other sites More sharing options...
Marine1Texas Posted December 15, 2016 Share Posted December 15, 2016 CPS Link to comment Share on other sites More sharing options...
thejim42 Posted December 16, 2016 Author Share Posted December 16, 2016 cps is good. still no spark. fuel pump comes on and i know the injector is firing because i keep getting fuel in the oil. but i have no voltage out of pin 27 at the computer which is ignition output. I also have no voltage on pin 6 which is input from the fuel pump relay. I know the relay is good because the pump comes on. so what is the voltage supposed to be from the fuel pump relay to the computer, and is there any connection or component between the relay and the computer? Where does the relay get its ground from? Link to comment Share on other sites More sharing options...
Dzimm Posted December 16, 2016 Share Posted December 16, 2016 Go through and check ALL the grounds. Always start with grounds because they usually are your problem. The easiest way to find them is to start at the battery and just start following wires to their destinations and clean every ground you find along the way with a wire brush or sand paper. Replace any super rusty or broken terminals along the way. Link to comment Share on other sites More sharing options...
Ωhm Posted December 16, 2016 Share Posted December 16, 2016 ECU pin 6 controls the grounding for the FP relay (pin 2(85)). If FP runs and injector is hot, good CPS. ECU pin 27 supplies square wave for ICM. Try reading voltage on a VAC scale while cranking the car. Hold gas pedal to floor, should shut injector off. Link to comment Share on other sites More sharing options...
thejim42 Posted December 16, 2016 Author Share Posted December 16, 2016 what should my voltage be? Link to comment Share on other sites More sharing options...
Ωhm Posted December 16, 2016 Share Posted December 16, 2016 I have no voltage value for you. Any reading above 0vac would indicate action on that circuit. Take reading at D2-9, no need to disconnect anything. Link to comment Share on other sites More sharing options...
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