96 K1500 crank, but no start

[bluedevil]

Hey guys,

My 97 k1500 has been acting up a little bit lately. Normally I don't post threads until I've done some digging into the situation, but I figured it couldn't hurt. The past couple weeks while your driving the truck, without warning the volts gauge would drop out quickly (sometimes making the truck shudder), then just as quickly jump back to its normal 14V (no warning light showing charging issues). However, when it does this, the seat belt light comes on and flashes, and chimes? Weird...Anyways, fast forward to a couple days ago, the truck has a crank but no fire condition sitting in the driveway. I did some preliminary fixing so far on my sub par battery connections, and then checked the alt wiring, and fuse box power supply connections, fuses, and relays. I thought I was on to something when I swapped out the fuel pump relay, as I was not noticing the fuel pump prime. It fired up, and all was good. The very next try was back to no fire. I find it odd that while its doing this, you turn the key to the run position, and the oil pressure shows 1/4 gauge. The volts gauge also shows nothing, even though battery has 12+V. My next steps, which should have been my first, are to check spark, and fuel pressure, and chase from there. I have another ignition switch that I might swap out also. My concern is that when you hear of guys with ignition switch problems, it sounds like its all or nothing, not what I have going on. The truck has no codes otherwise. Is there somewhere else I should be looking as well?

 

[LOUDRNU]

Sounds very frustrating, but does sound very similar to when I had a bad Ignition Coil that would intermittently act up and would even lead to a crank no start towards the end, other times it ran great.

It was hard to narrow down exactly what was causing it except most of the time it would happen at least after the truck was fully warmed up but it could be 15 minutes, 90 minutes, or some days not at all. I also had some gauges and lights drop or come on and would experience a shudder. After learning the cause (failing coil) I think the cluster issues were due to the truck damn near stalling for a moment and then jolting back to life.

I didn't think the coil was the problem because it had been less than a year since a full tune up was done. So in an attempt to solve the issue I replaced both the alt with an high output & also dropped in an Optima deep cycle batt. to sadly find out it was neither.

I also had a second coil do the same thing months later & then after replacing that its been fine for 4 years with no issues.

Sadly sometimes its the last thing you would expect & on the bright side can be simple...Hope this helps & Good Luck!!