Hello. I have a 2003 4.8L from a Silverado.
I put a 5.3L crank.
2005 5.3L rods (floater).
2005 4.8L flat top pistons (Floater).
COMP Cams 54-452-11 XFI Xtreme.
Edelbrock carb.
Factory coils.
New cam sensor.
New crank sensor.
I converted it to a carb cause it went into a '86 C10. The problem I'm having is it'll fire up run great, but when I shut it down and try to start it back up it backfires through the carb, but if I unplug the box then plug it back in after waiting 30 seconds before plugging it in it will start right up. Now it doesn't startup every time after plugging it back in, but 90% of the time it will. I've checked the pins and none were bent, 30 amp fused power from the battery with a relay, ground to the head and 4 AWG ground to the same spot from the battery, I have the dial at LS1. What's going on with it and how can I get a continuous start every time without unplugging the box? Oh and it's a LS series 60143 black and it's brand new. Thank you.
Have you connected this unit to a laptop yet to see if you are getting any error codes? On the sensors you are running what brand did you put into them? We have seen issues with a lot of off the selves brands, the one we see the least amount of issues are ACDelco sensors. If you cannot hook up to a laptop, what you can do to inspect the sensors is this, hook up a multi-meter to the feed wires to your sensors which are going to be either a pink or a orange wire depending on the harness you are using. The pink is 12 volts while the orange is 5 volts, so you will want to inspect to make sure it is getting the correct feed. Then you'll want to check the signal wire which is for the cam the brown with the white stripe and for the crank it'll be orange with a yellow stripe, depending on the feed wire you should see a fluctuation of voltage on those wires. If it has the pink wire, you should see 0-12V on them, if they have the orange feed wire, you should see 0-5 volts when you are cranking the engine over.
SCOOPE PROBES ATTACHED TO
BROWN Pin-6 Sensor Ground
ORANGE/YELLOW Pin-1 Crank
BROWN/WHITE Pin-2 Cam
WITH DC METER IT TOGGLED
I HAVE CAM AND CRANK SIGNALS, ALL CONNECTIONS ON THE 10 PIN MSD 6014 CHECKED FOR CONTINUITY FROM CONTROLLER TO THE END THAT CONNECTS TO THE REAR CAM/CRANK
CABLE.
+12/5 VDC GOOD
UNLESS HARNESS PINOUT ISSUE(MATCHES MSD PDF) IT APPEARS LIKE MSD 6014 TOAST.CRAZY THING IS SOMETIMES IT WILL SPARK ONCE ON A ODD CYLINDER AND QUITE.I HAVE ALSO NOTICED EVEN DOESN’T 100 % SPARK SENT BACK TO MSD TO GET CHECKED.WILL UPDATE ..
Last edited by hirdo@netzero.net; 11-03-2020 at 07:02 PM.
Reason: UPDATE