Question about 1990 Chevrolet C1500
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Posted on Jan 02, 2017
Not sure on that model what controls the injector pulse, but most vehicles either use the signal from the crankshaft position sensor or a cam position sensor. You should use a LED testlight, (NOT A BULB TESTLIGHT!!) and backprobe the injector terminals (with the other lead of the testlight to ground) while cranking the engine over. If the light flashes on one of the terminals, then you are getting injector pulse, and the fault lies elsewhere. If not, then you will need to replace whatver sensor is used to provide engine position signal on that model. Also, check the wiring to that sensor. Some vehicles have problems with the crankshaft pulley harmonic balancer failing and damaging either the body of the crank position sensor or its wiring.
Posted on Nov 02, 2008
the injectors are fired thru the engine cotrol module but it gets its signal to fire from the pick-up located inside the distributor if you are loosing injector pulse only the ignition module is bad if you are also loosing spark when you loose injector pulse your pick up is causing the problem if you replace the pick-up i recomend you change the ignition module when doing so because they work together and you have to remove the distributor to change the pick-up
Posted on May 31, 2009
Computer maybe, but it's not the most common failure. There is a hall switch and a "pole piece" on the shaft of the distributor just under the rotor. The ignition module just to the side of them usually affects spark. Sometimes it's easier to swap the distributor assembly if you know the procedure.
Posted on Sep 03, 2009
Testimonial: "Thanks alot man, really helpful for sure!"
You are jumping to conclusions. Slow down.
No spark AND no injector pulse indicates none of the desired outputs were triggered. The ignition module makes spark when it receives a crankshaft position sensor signal, and then transfers control of that spark to the computer after it starts. The module takes its crank sensor signal and generates an RPM count that it forwards to the PCM(main computer) which is used for triggering the injectors and controlling timing. SO, if you had a bad crank sensor OR a bad ignition module, you could lose both spark AND fuel. a coil would not disable injector pulse. modules RARELY fail in a manner that disables RPM reference to the computer causing it to not fire the injectors...At this point, I would TEST the crank sensor as the next step. If its easier, 1 of the wires on the module goes directly there so you can test the crank sensor at the module.
Posted on Sep 18, 2009
Testimonial: "great info, thanks!"
The ignition module located inside of the distributor is what generates the signal that the ECM (Engine Control Module) uses to time and fire the fuel injectors, as well as the signal to run the fuel pump and the dwell signal timing to fire the ignition coil. A faulty ignition module can cause any one of these systems to malfunction.
That does sound like a malfunction with the ignition module inside of the distributor, and you can remove the ignition module and have it tested for free at most auto part stores.
If you do purchase a new ignition module be sure that it does come with a silicone grease or a die-electric compound because it is a heat sink and the ignition module will burn up without it.
To install the new ignition module first clean out the mounting surface inside of the distributor. Then completely coat the metal contact surface under the ignition module with a thick coat the silicone grease or die-electric compound and do not leave any of the metal contact surface of the ignition module un-coated with the silicone grease or die-electric compound, and be very careful not to over-tighten the ignition module or it will be damaged.
Posted on Jun 22, 2010
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