No-Start Vortec 350

[bEnC10]

Hello everyone! This is my first time posting in a Forum like this, I would usually just find the information I need and it ends up working out for me. Anyway, I have a Vortec 350 (L31) out of a 1997 K1500 and put it into my 1986 c10. This was my first time working on a vehicle so YouTube was a really big help. I rebuilt the vortec 350 and added a slightly bigger cam and bored it out into a 383 (not a stroker). I paired it with the stock 4L60e. I got a Custom wiring harness made with everything that is only needed to run. Long story short, it cranks but doesn’t start. Here is a list of what I replaced and got brand new.

-New distributor, cap, and rotor with plug wires
-New fuel pump with new AN lines and filter
-Crank position sensor
-EGR valve
-New Ignition Coil

I didn’t want to get a new spider injector because I had the MPFI (rubber end) and not the other black plastic CPFI. I know that compression is good and I know I get spark because of the occasional cylinder going off when I’m cranking. I’m sure I am in time because I was back and forth with it for a while but finally I got it perfect on TDC. I have ~60 Fuel Psi when I’m cranking so I’m not sure what else it can be? Maybe an electrical issue? I’ve been trying to figure this out for a while but still nothing.

 

[Schurkey]

I rebuilt the vortec 350 and added a slightly bigger cam and bored it out into a 383 (not a stroker).

Not possible to bore a 350 enough to get to 383. Are you saying you bored it .030 as is typically done when building a 383? If so, you've got about 355 cubes.

it cranks but doesn’t start... ...I know that compression is good and I know I get spark because of the occasional cylinder going off when I’m cranking. I’m sure I am in time because I was back and forth with it for a while but finally I got it perfect on TDC.

WHICH "TDC"???

If you put the distributor in with the rotor pointing at #1, when #1 is at TDC Exhaust, the engine may backfire but it'll never run. You need the engine to be at TDC Compression when the rotor points at the #1 plug terminal on the cap.

If I'm correct about this, you'll need to pull the distributor up enough to spin the shaft half-a-turn.

You'll need a scan tool to get the distributor position fine-tuned correctly. This doesn't change the timing, but it does change the synchronization of the crank sensor signal and the cam sensor signal; and also the alignment of the rotor to the distributor cap terminals.

Make sure the plugs haven't fuel-fouled from the excessive cranking.

 

[bEnC10]

Yeah sorry I assumed it was a 383 bc I thought it was just a 350 but bored .30 over and stroked, but yeah I have a 350 bored .30 over

Also I set the distributor about 3 diffrent times before I knew I got it perfect. I put it on TDC on compression stroke and the rotor pointed to the 1st cylinder. The first time I set it the markings were different on the aftermarket distributor so it was rough and when I cranked it would back fire a lot. It would pop like crazy through the exhaust and through the intake. 2nd time I believed I had it 180 off so I flipped it and when I cranked it, it would only crank for a little, with a good battery. The last time I know for sure I got it because it sounds like it was trying to start with an occasional cylinder firing.

 

[PlayingWithTBI]

I know that compression is good

How do you know compression is good? Did you do a compression check?

If your distributor is stabbed right, and you're getting fuel, you may have the valve preload set too tight and not getting enough compression to get proper combustion.

 

[Jeff Janssen]

Yeah sorry I assumed it was a 383 bc I thought it was just a 350 but bored .30 over and stroked, but yeah I have a 350 bored .30 over

Also I set the distributor about 3 diffrent times before I knew I got it perfect. I put it on TDC on compression stroke and the rotor pointed to the 1st cylinder. The first time I set it the markings were different on the aftermarket distributor so it was rough and when I cranked it would back fire a lot. It would pop like crazy through the exhaust and through the intake. 2nd time I believed I had it 180 off so I flipped it and when I cranked it, it would only crank for a little, with a good battery. The last time I know for sure I got it because it sounds like it was trying to start with an occasional cylinder firing.

 

[Jeff Janssen]

Have you done an actual compression test on all cylinders? If the valve lash is not set properly then it may pop and sputter but not start.

 

[bEnC10]

I haven’t done an actual compression test, but I personally didn’t rebuilt the engine. I took it to a shop and they gave it back to me as a long block. So I assumed that everything would be fine. Also what is the valve lash? Like with the lifters?

 

[stutaeng]

Do your spark plugs smell like gas? If not, check that your injectors at pulsing with a noid light.

I've checked with an LED test light. It should blink.

 

[bEnC10]

I have a multimeter would that work with injector pulse? I’m about to get a compression tester to test it.

 

[PlayingWithTBI]

Also what is the valve lash?

Valve lash is when you set the gap between the valve stem and the rocker arm on a solid lifter cam. Valve preload is when you set the load on a cam with hydraulic lifters. You're tightening the rocker arm to zero lash then, tightening a little more. Everyone has a different method and tightening 1/2 turn to a full turn depending on each person's method.