# 1990 chevy 1500 wont start



## fireman c-6 (Nov 29, 2010)

i was driving to work and my motor lost all power. i went back later that afternoon and the truck started right up. got it on trailer and home and it wouldnt start. ive replaced the ignition switch on steering colume, ignition modual under distributer cap, new cap and rotar new coil and new fuel pump. every time i replaced a new part it would start right up and stay running. i would hop in to go to work the next day and it wouldnt start. it will crank over all day long but wont fire. any ideas on what else i should try. need help asap. thanks


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## octaneman (May 13, 2009)

Hi fireman c-6


In your post you said that every time you replace a component it would start right up, that means that every time you move the wiring harness the engine fires. You will need to check the ground straps that maybe broken, loose, or corroded. Grab hold of the wiring harness and wiggle it then try to fire up the engine. If it still doesn't want to start then you will need to test for open connection to ground. To do this you will need a test light, by removing the ground side battery terminal and connecting your test light from the terminal to the negative battery post. A brightly lit test light will indicate that there is a massive short somewhere, to find the short start removing the fuses 1-by-1 until the test light goes off. Once the test light turns off take note of which fuse goes to that particular circuit, break out your DVOM and do a continuity test on all components associated with it. 


post back your findings.


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## fireman c-6 (Nov 29, 2010)

octaneman thanks for the tips. i tested negative termnial to battery and she lit right up. i pulled all the fuses and it never killed the test light. we shook and pulled all the wires and still never shut the light off. any ideas on what grounds i need to be checking next.thanks alot for the help


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## octaneman (May 13, 2009)

The most common ground problem is ground to the computer, injectors and the main ground that is connected from the battery to the engine block. Engine vibration and corrosion wear out the surface contacts that make up a closed circuit. An engine computer not grounding properly gives off all kinds of symptoms that are difficult to hammer down, so be diligent when making your inspections on wires. Disconnect all ground wires that you are able to locate in the engine then clear off any corrosion with emery cloth and re-do your connections super tight.

I must point out that when doing the open to ground test with your test light, the doors of your car have to be closed. When you leave any door open the ground circuit isn't complete so your test light lights up super bright. The next part of the open to ground test is see if the starter or the alternator are grounding out. Fuses inside the cabin are not the only ones your vehicle uses, there is also fusible links and relays that need to be disconnected to make a thorough investigation. 

Re-do the test and this time disconnect the alternator wires and see if it shuts off. If it doesn't shut off leave the alternator disconnected and then remove wires to the starter. By disconnecting one or the other, you should see a significant drop in brightness from the test light or complete shut off. Keep in mind that the starter, alternator and radio are the biggest current drawing components in the electrical system, they are usually the main suspects when dealing with large current drains.


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## fireman c-6 (Nov 29, 2010)

Thanks so much. I will redo my test and update you tommorow. Thanks again.


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## fireman c-6 (Nov 29, 2010)

octaneman,
I did the test doors shut started with altenater and starter then the radio connections and had no luck, however i noticed my brights were on so i went to switch them off and the switch had no click to it and the brights wouldnt shut off. so i played with it awhile and got the brights to shut off as soon as they did the test light went off as well. could it be possiable i have a broken wire in that switch that is arching against the steering colum. i think i will replace the whole colum instead of trying to split it apart. let me know what you thing before i ripp the colum out. thanks


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## octaneman (May 13, 2009)

Good job ! You have isolated the problem, now don't be in a rush to rip out the whole column to effect repair, take the job one step at a time. First thing you need to do is get a diagram with an exploded view of your steering column. You will find your diagram here: http://www.autozone.com/autozone/homePage.jsp

The diagram will help you get access to the inside components without breaking anything. If your switch is integrated with your flashers, (combination switch) and is bolted on to the lower collar of steering wheel, then that is the only thing you need to replace. It's very important that you verify that the switch is causing the problem, so break out your DVOM and set it to continuity. Disconnect all plugs that is connected to your switch and perform the open to ground test on all wires and switches that is on the column. 


Question: Is your gear selector on the floor or on the column ? 


Note: Take extreme care when probing wires under the column, under no circumstances will you probe wires to the air bag systems. Follow your schematic diagrams to the letter, any accidental grounding to the air bag circuit will deploy the bag prematurely causing serious injury or death.



post back your results.


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