Timing issues

[Bradley Ferris]

I just put a new 6.0 long block in my 2002 chevy Silverado and it won't start.  All new sensors, plugs and wires. When I go to start it it back fires through the intake. Plugs are soaked in fuel as well. I've checked to make sure nothing is unplugged....any suggestions?

[Jsdirt]

Was the long block meant for a newer truck? Reason I ask is, past a certain year, there are different reluctors on the flywheels for the crank sensor, depending on the year. Neither will run when running the wrong flywheel. 58x is the newer one, 24x is the older one. I forget what the cutoff year was. Might be '07.

 

If that is all set, the crank sensor and wiring, and ALL wiring are the main focus. Make sure every single ground is where it's supposed to be, and tight on a CLEAN connection, and be sure no wires got pinched in the bellhousing, or engine mounts.

[Bradley Ferris]

Yes I ordered from powertrain products they matched the vin to the motor. Does the flywheel have a certain way it needs to be installed? Meanin does it have to align in a certain way with the crank shaft? There is one ground that I may not of gotten landed in the correct spot on the back of the block no wires pinched or broken and all landed correctly. I'll check the ground in the morning and let you know appreciate the ideals. Thanks

[riverbanks]

What about,pull fuel pump relay,pull #1 plug out,put plug back in wire,put finger in (on)plug hole,have someone bump motor over while you watch for spark and feel for compression?

[Bradley Ferris]

Ok I have fuel and have fire and it seems to be about the right time when fire is needed. Only other thing is air. So I used a scanner earlier it said no codes were stored but also said they the on board computer hasn't completed a diagnostics test yet. I waited quite some time even reset computer still some thing though. Any ideas?

[Doug_Scott]

Pretty sure the engine has to start before it will complete the tests.  

 

Flywheel will only line up one way. The backfiring makes it sound like your timing is 180 degrees off.  Do a search on Google for instructions on installing cam and crank sensors.