96 c1500 vortec 5.7 crank no start

[Jerry H]

i have a 96 c1500 5.7 vortec. it cranks but doesn’t start. i changed the plugs today put ac delcos in. it has a new starter new battery new distributor cap and sensor and plenty of fuel pressure. it has spark and fuel and i just put the crate motor in about 25k ago. please help thx

 

[HotWheelsBurban]

Check the Crank fuse in the dashboard fuse block, I think it's a 20amp but it should say on the door to that fuse block or in your owners manual. You changed the distributor cap, did you replace the rotor too?

 

[Jerry H]

i did not replace the rotor but it didn’t look to bad it only does this crank no start in the winter summer is perfectly fine

 

[Jerry H]

i’m just really confused by it

 

[gmcyukondriver]

Are you 100% sure you're getting fuel AND spark?

Engines need three basic things: air, fuel, and spark. The last two are usually the issue when it will crank and not start.

You can get a tool that goes between your spark plugs and wires, and it has a window to confirm you're getting spark. I've dealt with this issue on two trucks, 95 TBI and 96 Vortec. Both times, it was the Ignition Control Module (ICM). About $90 from most auto parts stores. I would check that first.

 

[MrOverCast]

i’m just really confused by it

Check for spark. If it has no spark usually that means the engine harness isn't getting power or the crank sensor is broke. I've powered up one of these vortec harnesses on a Walmart table and even with every sensor disconnected it still sparks the coil. If it does have spark check your fuel pump then

 

[Jerry H]

i checked my fuel pressure last night it hours up to about 50 55 and doesn’t moved when i turn the key back off. so that means i don’t have a stuck injector. i checked spark all there and good. i don’t understand why it only does this in the winter.

 

[MrOverCast]

i checked my fuel pressure last night it hours up to about 50 55 and doesn’t moved when i turn the key back off. so that means i don’t have a stuck injector. i checked spark all there and good. i don’t understand why it only does this in the winter.

Check your sensors too. If you have a scan tool obdlink or something take a loot at the sensors and see if any are out of wack. Example. -77 or something.

 

[Jerry H]

Check your sensors too. If you have a scan tool obdlink or something take a loot at the sensors and see if any are out of wack. Example. -77 or something.

i have a simply obd2 scan tool but idk what i would look for like the name. but what do you think about it only doing it in the cold

 

[MrOverCast]

i have a simply obd2 scan tool but idk what i would look for like the name. but what do you think about it only doing it in the cold

Might be the intake air temp sensor. how does it run when its fully warmed up?