Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
The most common faults causing a no spark condition on the 4.3L engine are faulty ignition coil wire, moisture inside the distributor cap or faulty ignition coil. It sounds like you have already covered these bases. Other things to consider are the ignition module and pick up coil wich you have already tested. The ohm reading for the pick up coil sounds good to me, however I am not a big fan of electrical parts from or electrical parts testing at Auto-zone. For know lets trust that the ignition module is ok. The next component you should suspect is the crankshaft position sensor (CKP). Make sure it is pluged in and that the wires are not damaged. It should be in the timing chain cover near the bottom of the ballancer. I do not have the ohm spec for testing it at home but it should generate an alternating current whenever the engine is spinning that increases with rpm. If your repair manual does then by all means test it. When I get to work tomorrow morning I'll see if I can find an ohm test for it. I live in the pacific northwest and you should hear from me around my 10 AM break.
I may have made a mistake by having you look for the crankshaft sensor. I forgot that in 93 there are two types of 4.3L engines one has fuel injectors on top of the throttle body that you can see inside the air cleaner, there will be two electrical connectors, and the other does not. Wich one do you have?
Ok this is throttle body injection If you dont mind I would like to start from the beginning, when checking for spark I like to use an old spark plug, remove the coil wire from the distributor install spk plug and set it on intake manifold so I dont zap myself then crank engine I also like to lift off air cleaner so I can see if the injectors are squirting fuel this way you can see if you have spark and fuel delivery at the same time. If a spark plug is not available you can pull the back the boot an the end of the wire and do the same as with the spk plug but the wire wust be close ground like 1/8 in or so.
The reason I asked about fuel injectors is that the signal from the pick up coil is necessary for the fuel injectors to operate. I am 99.9% sure that you have a faulty ignition control module. You have 10 or more volts at terminal "C" and "+" . You have tach signal because the injectors are operating. The only thing left is a faulty Ignition control module. The only way to know for sure is to get one and install it. I bet it starts right up.
Glad that I was able to help solve your problem, and yes clicking the Accept Button is all you have to do. Sometimes when a module fails it still sends the correct signal but the signal is very weak. This weak signal is picked-up by the test equipment and the module passes the test, however this weak signal is not strong enough to trigger its companion component in this case the ignition coil. I think that you can access my profile from the main page and request that I answer any questions. Keep in mind though that my fellow experts are also good and can help you as well as I. Thank You, atcat