LS3 Crate Motor Won't Start

[66ChevyMax]

Let me clarify it has started many times but now it won't.

This is a new crate engine purchased from Scoggin Dickey Chevrolet. It's in my 1966 C-10 and has been started many times. I have taken I on a dozen test drives and would say then engine has probably 2 to 3 hours worth of run time.

The last test drive the only thing that was changed is I hooked the alternator to the battery, gauge showed about 15 volts, drove the truck for a bout 3-4 miles and parked it in the driveway. About 15 min later I started it up again to move it into the shop, it ran for about 10 sec then sputtered and died.

When I tried to restart it didn't sound right, some knocking sounds, would sputter but not run. Pushed into the shop and called it a night.

Next day, remove power from ECM, turn motor over no noises and had oil pressure, hooked ECM back up, turns over great no noises and has fuel and oil pressure but doesn't even attempt to fire.

Any ideas or direction would be greatly appreciated.

See build thread below.

[cru_zn_29]

How about a squirt of fuel or starting fluid to see if need fuel or spark.

[66ChevyMax]

I have not tried that, I have a pressure gauge on the fuel rail and have 60-65lbs of pressure. It would eliminate the question though, will try.

Thanks,

Originally Posted by cru_zn_29

How about a squirt of fuel or starting fluid to see if need fuel or spark.

[cru_zn_29]

Not if your injectors are not opening.

[66ChevyMax]

Good Point, I'm going to see if I have any codes before I proceed.

Originally Posted by cru_zn_29

Not if your injectors are not opening.

[BR3W CITY]

What do you mean by "hooked the battery to the alternator"...did you not have the alt hooked up before when the vehicle ran?

Its possible you fried the injector driver on the ECM (or it just went bad). Try ground the outside of the ECM case and see if it will start.

[66ChevyMax]

No I would charge the battery, they were just short test drives.

Before I put the hood on, the ECM was just sitting in the windshield wiper area, I mounted the ECM to the firewall before the last test drive because I had the hood on and it ran great????

Originally Posted by BR3W CITY

What do you mean by "hooked the battery to the alternator"...did you not have the alt hooked up before when the vehicle ran?

Its possible you fried the injector driver on the ECM (or it just went bad). Try ground the outside of the ECM case and see if it will start.

[66ChevyMax]

Ok found the problem, I strapped the fuse box to the inner fender for the first time since I had the hood on. I didn't put the cover on the fuse box so the strap went across the ignition relay and all the vibration wiggled it loose. Removed strap pushed ignition relay back in and she fired right up.