My wife and I recently got a problem with our 2003 gmc safari van. It turns over, but it's not sending spark to the spark plugs. To be honest, neither of us has any experience with auto repair. So we're stumped. Also, the clock is ticking because if we can't move it within a week, we'll lose it to the tow yard. Any help in this matter would be appreciated. Thank you for your help.
Your van is 20 years old so you guys are going to want to buy a scanner.
In the "Tools" link on the upper right of the page there's an Ancel AD410 for $40.
There's also a comprehensive review/comparison of scanners in the FAQ that's posted as a sticky on the top of the page.
So in your case it would be helpful to plug in a scanner and see if there's an RPM signal while cranking. (No RPM signal means No Spark)
If there isn't a RPM being displayed during cranking then the crankshaft position sensor would be the low hanging fruit.
But you don't want to just start throwing parts at it. Buy an inexpensive scanner. It will pay for itself because you can check if a component is functioning before buying a part and hoping it will work.
In this case, if you're seeing RPMs on the scanner during Cranking then it isn't the crankshaft position sensor.
You don't need to know how to read the scanner. Plug it in and there's plenty of guys here that will walk you through it.
In the meantime don't lose it to a towing company. If you run out of time ,pay the $70 to have it towed to another location so you can buy some time if you need it.
Well we had a mechanic friend come by with a scanner. He's since bailed on us. Either way, he said the scanner had some problem linking to the van. He did the spark plug test and that's how I know it is a spark issue. Where wound I go about finding the crank position sensor?
PS we live in the city. If they tow us, we're not given that option. They tow straight to the yard.
You can try the crank sensor without doing any testing and hope you get lucky. Sometimes you do and sometimes you don't
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The fact that your friend's scanner couldn't communicate with the car's computer is something else to consider. Is this a network communication problem? Or maybe the fuse for the power to the Data Link Connector is blown? (passenger compartment fuse box, fuse #7)
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And although I mentioned the crankshaft position sensor (under the crankshaft pulley in the front of the van) as a possible reason, I could have just as easily mentioned the ignition coil, ignition control module, distributor, distributor cap/rotor, ignition switch, or a circuit issue as the possible problem
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So you can see why you don't want to change every part which someone mentions as a possibility
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A scanner would have made it easy to see if the computer is getting a signal from the crank sensor or not
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Your friend did "the spark plug test" at a spark plug wire (I presume) and found No Spark. Well all of the things I listed above could be the cause of that too
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So let's put aside that you can't communicate with a scanner through the data link connector for the moment
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1st, check the fuses. For example if the ECM-1 fuse (underhood fuse box) is blown you won't get power to, the Fuel Injectors, Crankshaft Position Sensor, Ignition Control Module, and the Ignition Coil. (That would cause No Spark as well as no fuel through the fuel injectors to the cylinders). But check ALL the other fuses too
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If the fuses check out OK and you decide to maybe do a little testing before replacing the crankshaft position sensor then at the very least you'll need to buy an LED Test Light and an HEI Spark Tester
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You need to see if the ignition coil is creating spark to send to the center of the distributor cap (and onto the spark plugs)
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If the ignition coil is creating spark then you can concentrate on the distributor, distributor cap and rotor, and spark plug wires
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But if the ignition coil isn't producing spark you need to check if the ignition coil is getting Power on the Pink Wire, and a Ground Switching Signal coming from the Ignition Control Module on the Black w/White stripe wire
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If there's Power and a Ground Switching Signal on those wires then you have a bad ignition coil. If there isn't you can do a similar test on the wires on the ignition control module and the crankshaft position sensor
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You can go to this page on this link to see how to use the HEI Spark Tester to check if you're getting spark from the coil to the distributor cap (he's doing it on an 8 cylinder engine but the test is the same for your 6 cylinder)
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(He just unplugged the wire coming from the ignition coil on the distributor cap and stuck his HEI Spark Tester into that wire and cranked the engine to see if there's spark coming from the ignition coil)
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https://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/ignition-misfire-diagnostic-tests-4
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Additionally, the ignition coil circuit tests and the ignition control module test are covered in the other pages of the link above but you don't need a multimeter (like he uses in some of the tests) you can use the LED Test light instead (and you don't have to make one like that old tutorial says. You can buy one at the auto parts store)
Where wound I go about finding the crank position sensor?
You still don't know if the crank sensor is at at fault. As far as its position, it took about 10 seconds to find this:
https://www.astrosafari.com/threads/crank-shaft-position-sensor-location.77522/
"front of motor on the bottom, right on the crank pulley, easy access"
https://www.youtube.com/watch?v=vtnmzNFLed4
