Hello everyone I have a headache of a 5.7 Tahoe and I'm currently getting no spark I've done a bunch of test and am kind of stumped at the moment.
I tested the wires with a spark tester and no spark.
Checked the distributor, coil and ICM for power and ground they're getting power and ground perfect so I tested for spark from the coil and i'm not getting any spark from the coil.
In a blind leap of faith i replaced the ICM, the cam and crank sensor they looked old and there was decent sale anyway so i just replaced them all and guess what still no spark.
I tested all the fuses and none of them are blown and i'm getting power on both sides from them.
I hooked up a test light to the positive terminal and probed all the switch signal wires and here's the weird thing the light is only lighting up when the key is in the off position when i turn it on or crank the light stays off.
I'm leaning towards maybe an ignition switch but from other videos i've seen when the switch was bad they still had a ground signal with the key on I only have it with the key off.
with the switch being like $160 i don't want to just throw a switch at it but at the same time the ground for the ICM tested good and the wiring diagram doesn't show any grounds between the PCM and ICM.
Any help would be appreciated i've been going at this for over a week when I have some free time. Thank you.

 

Crank sensor replacement requires a relearn procedure via a high end scan tool.
Many modules ground the sensors and components, not supplying power to the component.
I had to replace the junk plastic distributor in my old '99 Yukon as it was giving me erratic misfires. I no longer have diagrams for it anymore.
Check relays, they go bad, similar ones can be swapped around for quick checks.

 

The distributor body was plastic? How do you like your 15 Chevy Malibu? Love mine with the 2.5 liter. Great motor, no turbo!

 

Yeah '99 5.7 had a plastic distrib. body and cap screws would strip out or crack the body. My '15 is also a 2.5 . I installed a Trifecta tune in mine to get rid of auto stop and with the tune it actually drives and shifts pretty darn sporty. If you enjoy sporty I'd recommend it highly. No turbos for me and I hate auto stop so it's been eliminated from happening in my fleet.

 

Unbelievable! I have literally never seen a plastic distributor in my life. I'd chuck that out in a New York second too. I love the 2.5 liter in my Malibu. It's sporty enough for me. Took some getting used to no transmission dipstick and no way to change the filter, however.

I've become used to the auto/stop, and I can keep the motor going 90% of the time. I'll just chuck the battery for a resistor setup when it goes, so the panel light won't show. Not paying $100 USD for a new one.

 

I agree. Turbochargers are fine on a diesel motor, or if one is racing (I'd prefer a supercharger myself, as you can kick them off easily) but my 15' Chevy Bu' does a fine job of producing HP without a turbocharger, heating up the motor oil, nor needing any work on it, ever. With close to 200 HP, she will move out, when I need her to do so, always.

 

The Trifecta tune limited the constant back shifting in/out of overdrive that the factory program does with light throttle pressure. Less shifting = longer life in my book. Definitely more mid range punch, top end seems the same for a 4 banger.