Changed plugs and alternator belt. Ran great and now won't start

[DavidZ71]

It's a 2004 Chevy Tahoe Z71. Fantastic dealership maintenance history. I changed the plugs and alternator belt along with tensioner and idler last night. Started her up afterwards and ran great. Parked it outside overnight and now I get a crank but no start. It will act like it will start for half a second and then go back to merely cranking.

Battery is newer and is sitting at 12.4 volts. I hear the fuel pump prime when I turn the key. I thought gas may be too low (a bit more than 1/8 of a tank) but I added a gallon and there's no difference.

Any ideas on what's going on?

 

[SnowDrifter]

Intake boot on all the way? Maf plugged in? Gapped plugs to spec? Checked all boots/wires are in place, plugs are snug? Injector harness plugged in and tight?

If all of that checks out, unhook the ground on your battery and go depress the brake pedal for 20-30 seconds to drain any capacitance from the smart bits. Hook the battery back up and see where that gets you. Goal here is to reset any volatile / temporary memory in the computers, it's possible some weird bit flipped somewhere and is making it goofy.

 

[OR VietVet]

Attach a fuel pressure gauge and get that reading too but what @SnowDrifter said is a good place to start. Inspect the entire area where you did your work.

 

[DavidZ71]

MAF is plugged in, intake boot is on properly, plugs are torqued to 13lb/ft, wires are on properly, injector harness is connected. I disconnected the battery and tried again and still same results.

It's odd the Tahoe ran great right after I finished all the work and now has decided it doesn't want to

 

[DavidZ71]

Maybe I damaged an ignition wire when I was pulled them off the old plugs

 

[swathdiver]

Maybe I damaged an ignition wire when I was pulled them off the old plugs

Should still start though.

 

[OR VietVet]

Unless you damaged all 8 wires....you could have a damaged one but would just be that cylinder having a miss. I would have done the wires at same time as the plugs.

 

[DavidZ71]

I was going to but I ordered round coil wires by accident so I just reused the old ones. They're AC Delco premiums. Had zero issues prior to changing the plugs and belt but again, it ran perfectly after the work, too

 

[Fless]

Attach a fuel pressure gauge and get that reading too but what @SnowDrifter said is a good place to start. Inspect the entire area where you did your work.

^^ This. Sounds like the fuel pressure and volume isn't enough to keep it running. Prime the pump a few times by turning the key to run, then back off, several times without cranking. Then crank it and see if it will run.

Reach under the truck and whack the fuel tank a few times while it's being cranked if you have help. Otherwise bang it like that, then jump in and try again to start it.

Do the fuel pressure test at the fuel rail.

 

[SnowDrifter]

Also: have a code reader? Anything pending?