Carbed 5.3 won’t start please help!

[68 P.O.S.]

Looks much better now!

[jjzepplin]

Yup!

[geezer#99]

You got the primary transfer slot set.
How’s the secondary transfer slot look?

[Rdwagoner]

I didn’t mess with secondary at all. The secondary transfer slot wasn’t exposed at all to begin with. Didn’t get a chance to fire it back up today. I got side tracked making the adjustment and installing some gauges. Will fire it up Thursday and see how it runs.

[Rdwagoner]

Alright gentleman, I went to crank her up today and it just turns over. I have spark, I had my neighbor hold the plug to the block and it lit him up! Lol
I’m gettibg a cam sensor fault on my MSD software while trying to crank. I got one last time but it still fired up. Not today though, will that sensor being bad not let it crank up? Any ideas?

[AussieinNC]

OK..you have spark...

What about gas ? Spray a little ether down the carb and hit the key...if it gord to start...check for fuel in tank....clogged line, stuck flaot etc

If it doesnt fire ...it is most likely the crank sensor gone bad....

Cam sensor errors are not a common non start issue...did you put new ones in during the build...

Check all connections...

[Rdwagoner]

Fresh gas in tank, new fuel lines from tank to new carb. Fuel in bowls, new sensor on order as of this evening.

[Rdwagoner]

Replaced the cam sensor and the crank sensor. Fires up and runs now. I still have the check the transition slot because it seems to not want to run at all with the slots adjusted to a square. I had to open up the slots more in order to get it to run decent. I do have an aggressive cam so maybe that why?

[68Stepbed]

Originally Posted by Rdwagoner

Alright gentleman, I went to crank her up today and it just turns over. I have spark, I had my neighbor hold the plug to the block and it lit him up! Lol
I’m gettibg a cam sensor fault on my MSD software while trying to crank. I got one last time but it still fired up. Not today though, will that sensor being bad not let it crank up? Any ideas?

Originally Posted by Rdwagoner

Replaced the cam sensor and the crank sensor. Fires up and runs now. I still have the check the transition slot because it seems to not want to run at all with the slots adjusted to a square. I had to open up the slots more in order to get it to run decent. I do have an aggressive cam so maybe that why?

I had a similar issue with the sensors. Here's a quick rundown of how the sensors work. The cam sensor typically only works to tell the ECM/MSD what position it's in in order to send spark to the correct side to start the engine. Once started, the ECM/MSD never reads the cam sensor again until the engine is shutoff and restarted. So, if there's a cam sensor fault, it sends spark to random cylinders until it hits one on the correct stroke. Many times, this may cause the same scenario as a distributor being installed 180 degrees out.

As for the transfer slot issue, there's a couple options. First, you need to make sure you have the correct size power valve(PV). That carb comes with a 6.5 PV. Typically, the PV number needs to be HALF of what your optimal vacuum is at idle. Which means a 6.5 PV needs at least 13" of vacuum.

Here's a good video explaining power valves.
https://www.youtube.com/watch?v=RvlmJoeIcpw

Check out this video for transfer slot and idle circuit tuning.
https://www.youtube.com/watch?v=JDPwY0LbRVY