Has spark no injector pulse has power to the injectors
No pulse means the injector ground side is absent, since you have power to the injectors. The ground wire goes into the engine computer to be internally grounded for the pulse. You can test the injector ground side with a test light, as a verification of it not having pulse. If it really has no pulse, but it has correct voltage to the injector solenoid, then you have a bad injector, or a bad ground wire to the pcm, or a bad pcm.
Use a test light with a ground clip and a needle-type probe. Unplug the injector connector and note which is the power wire terminal and which is the ground wire terminal. Clip the test light lead to the POSITIVE battery post, and put the probe into the injector's ground wire terminal. Now have someone crank the engine over and watch for a blinking light on the tester. If you have a blinking light, the injector ground side is working right, so check if voltage to the injector is correct, or if you have a bad injector. If you have no blinking light, then no pulse is correct. You will need to check the ground wire to the computer before assuming a bad computer. I think they are called quad drivers inside the computer that control the injector grounds.
Best way to check that ground wire is, first, take off the negative battery cable, then pull off the computer connectors, then use an ohmmeter to check resistance of wire from injector terminal to the pin on the computer's connector. Low resistance, low ohms, means the wire is good. ...But first I guess you will have to find the pin-out diagram for the computer, where and on which connector that ground wire goes in at. There's around a hundred or more wires going in, so color coding, tracing by the color of the wire would be a royal pain. Good luck, Scott.
May 07, 2015 |
Cars & Trucks