good day fellow techs and mechanics.

I'm working on a 98 GMC k-1500 that my friend bought over a year ago. with all the little fixes we've done and some other repairs ,it finally has given me a headache. started as a hard start ,then while he was in Utah it quit. a shop replaced the fuel pump[ dealer]started and has been working great till about a month ago.

I began with the basics fuel pressure test key on 65 psi. cranking pressure 62 to 68 psi' then I checked spark with a inline spark tester for the wire to plug. even hot spark. when I start cranking the engine the fuel pressure is 60 and spark is hot, should start when I release the key. it fails to start when key is released, yet all the gauges and dash works. first diagnosis brought us to the column harness and worn ignition housing. I replaced the whole column reset the security system. still doing this. at time it also wont do anything at all when key goes to start position. thanks for reading , chris

 

Here is a simple reply with no adjectives and no links, as you asked:

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It sounds like you have two issues. One is the no-start when the key comes back to the run position. The other is the no-crank at times.

For the no-start, check power to the ignition coil and the injectors in the run position. Many GM trucks lose power on the pink wire when the switch moves from crank to run. This points to a bad ignition switch or a bad feed from the switch. Even if you replaced the column, the switch or wiring can still be the cause.

Also check the ground at the back of the block and the ground strap from the frame to the battery. A weak ground can drop power when the key moves.

For the no-crank, check the neutral safety switch. Try to start in neutral. If it works in neutral, the switch is out of position.

If you can, use a test light at the ignition switch output. See if the crank wire and run wire both show power when the key moves through each spot. That will point you to the right path.