No-Start Vortec 350

bEnC10

Newbie
Joined
Jun 21, 2022
Messages
14
Reaction score
8
Location
Texas
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.
 

Attachments

  • 5D0E8664-F1AC-4C20-B5ED-CF921C5CC031.jpeg
    5D0E8664-F1AC-4C20-B5ED-CF921C5CC031.jpeg
    101.3 KB · Views: 7

Schurkey

Supporting Member
Supporting Member
Joined
Jan 14, 2018
Messages
7,257
Reaction score
8,065
Location
The Seasonally Frozen Wastelands
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.
 
Last edited:

bEnC10

Newbie
Joined
Jun 21, 2022
Messages
14
Reaction score
8
Location
Texas
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

Desert Old Guy
Supporting Member
Joined
Jan 3, 2019
Messages
8,075
Reaction score
11,423
Location
Tonopah, AZ
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

Newbie
Joined
Mar 29, 2021
Messages
25
Reaction score
22
Location
Chilliwack
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

Newbie
Joined
Mar 29, 2021
Messages
25
Reaction score
22
Location
Chilliwack
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

Newbie
Joined
Jun 21, 2022
Messages
14
Reaction score
8
Location
Texas
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

I'm Awesome
Joined
Aug 7, 2019
Messages
3,412
Reaction score
4,306
Location
Dallas, TX
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

Newbie
Joined
Jun 21, 2022
Messages
14
Reaction score
8
Location
Texas
I have a multimeter would that work with injector pulse? I’m about to get a compression tester to test it.
 

PlayingWithTBI

Desert Old Guy
Supporting Member
Joined
Jan 3, 2019
Messages
8,075
Reaction score
11,423
Location
Tonopah, AZ
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.
 
Top