New crate 5.3 motor won't start

taho · May 4, 2015

I have been on here for awhile now just never posted anything. Now I need some help. I got a 2005 Chevy Silverado Z71 with the 5.3(L33) in it. Hydro locked my orginial motor with 170,000 miles on it. Ended up breaking the #7 piston rod and cracked the block in 3 places. Dropped a new crate motor in it and after getting everything hooked up, the new motor turns over fine, getting fuel but we can't get any spark from any of the coils. Used one of those spark testers to test each coil. Checked and read out all the grounds and they check good.(maybe I don't have them in the correct location?) Looked the motor over and over looking for something we may have forgot to hook up but can't find anything not hooked up. It has brand new acdelco plugs and wires. Only codes were the front wheel speed sensor because we unhooked them and forgot to hook them back up. Even tried replacing the crank sensor. Any ideas? Is there any relearn procedure I have to do?

Beer Belly · May 4, 2015

Not sure if this is of any help. I was told the new motors have a different firing order for AFM.

Duelin · May 4, 2015

Check and see if you have a RPM reference.

taho · May 4, 2015

Not sure if this is of any help. I was told the new motors have a different firing order for AFM.

My truck never had AFM and the new motor was for 2005-2007 trucks so it shouldn't be an AFM motor

.

Check and see if you have a RPM reference.

. Rpm guage quite working a long time ago. I guess they were recalled because of the stepper motors in them!

Duelin · May 4, 2015

You mentioned codes so I assume you had a scanner hook up. Well hook it up again. Scroll to RPM's and crank the engine over. Do you have a RPM reference?

taho · May 4, 2015

You mentioned codes so I assume you had a scanner hook up. Well hook it up again. Scroll to RPM's and crank the engine over. Do you have a RPM reference?

I don't think my code scanner has that ability to do that but I'll check this evening when I get off work.

Daryl LBZ · May 5, 2015

Not sure if this is of any help. I was told the new motors have a different firing order for AFM.

L33 does not have AFM.

As for the issue of not getting spark, I've had this happen to me before with an LT1 Camaro. The problem with it was the ground for the computer was in the wrong place. Not sure if this is your issue though? I just swapped an L33 last week into my truck. And I can tell you that there should be two wires ground on the top of the motor behind the intake manifold, two more grounds on the side of the engine block underneath the motor, and the ground strap beside the brake booster/master cylinder gets put on one of the studs that bolts the transmission to the engine.

taho · May 6, 2015

L33 does not have AFM.
As for the issue of not getting spark, I've had this happen to me before with an LT1 Camaro. The problem with it was the ground for the computer was in the wrong place. Not sure if this is your issue though? I just swapped an L33 last week into my truck. And I can tell you that there should be two wires ground on the top of the motor behind the intake manifold, two more grounds on the side of the engine block underneath the motor, and the ground strap beside the brake booster/master cylinder gets put on one of the studs that bolts the transmission to the engine.[/quote

Can you take a picture of the grounds? Thanks in advance...

Daryl LBZ · May 6, 2015

L33 does not have AFM.
As for the issue of not getting spark, I've had this happen to me before with an LT1 Camaro. The problem with it was the ground for the computer was in the wrong place. Not sure if this is your issue though? I just swapped an L33 last week into my truck. And I can tell you that there should be two wires ground on the top of the motor behind the intake manifold, two more grounds on the side of the engine block underneath the motor, and the ground strap beside the brake booster/master cylinder gets put on one of the studs that bolts the transmission to the engine.[/quote

Do you take a picture of the grounds? Thanks in advance...

Not at the moment, but I can get you some pictures tomorrow in the daylight.

taho · May 6, 2015

ame="Hercmech" post="1621232" timestamp="1430880829"]

Not at the moment, but I can get you some pictures tomorrow in the daylight.

That'd be awesome. Thank you!

Daryl LBZ · May 6, 2015

That'd be awesome. Thank you!

No problem. I have to tinker with it some more tomorrow so I'll get a few pics of what I can then.

Daryl LBZ · May 6, 2015

Hope this helps...

Ground strap that goes to the transmission/engine stud

Ground wire from the body to the hood

There will be two grounds here on the passenger side behind the intake manifold. That small wire is one of them, can't see the other in this pic.

Then there is this ground I believe from the negative battery side and it's bolted to the side of the block along with another ground also.

taho · May 7, 2015

Hope this helps...

Ground strap that goes to the transmission/engine stud

Ground wire from the body to the hood

There will be two grounds here on the passenger side behind the intake manifold. That small wire is one of them, can't see the other in this pic.

Then there is this ground I believe from the negative battery side and it's bolted to the side of the block along with another ground also.

Thank Daryl! Last picture saved me. You are correct about the negative battery ground and the other is for the coils which I did not have in the correct location. As soon as I hooked it to the block I got spark and the motor fired right up! We had it on a plastic bracket which obviously isn't going to work.. Also why is the hood grounded? Me and my buddies can't figure out why the hood needs to be grounded...

Daryl LBZ · May 7, 2015

Thank Daryl! Last picture saved me. You are correct about the negative battery ground and the other is for the coils which I did not have in the correct location. As soon as I hooked it to the block I got spark and the motor fired right up! We had it on a plastic bracket which obviously isn't going to work.. Also why is the hood grounded? Me and my buddies can't figure out why the hood needs to be grounded...

Awesome good to hear! No idea why the hood needs grounded? Your guess is as good as mine on that one. Lol!

Chris · May 7, 2015

Awesome good to hear! No idea why the hood needs grounded? Your guess is as good as mine on that one. Lol!

Thank Daryl! Last picture saved me. You are correct about the negative battery ground and the other is for the coils which I did not have in the correct location. As soon as I hooked it to the block I got spark and the motor fired right up! We had it on a plastic bracket which obviously isn't going to work.. Also why is the hood grounded? Me and my buddies can't figure out why the hood needs to be grounded...

Because the hood is metal and all the metal is grounded.