5.3 start problems

[afcamaro]

I am having a few issues starting my 5.3 swap into my 72. Everything is working, the gauges and fuel pump kicks on but there is no power going to the starter. It wont even turn over. (should i test light the starter while someone tries to turn the ignition over?)

Now the harness does have a neutral safety still on it.
I do have the new brake switch installed for the swap.
The computer came off the same truck and has been programmed to who knows what but all the security stuff has been removed.

I am just wondering where I should start looking to find the problem. Harness was "professionally" done. Any help is appreciated. Thanks

[joesgreen67]

Not to sound silly, but did you connect the purple wire going to the starter solenoid? That wire needs to be connected to the starter switch.

On my harness it was marked "connect if required"

[afcamaro]

Yes I did connect that. It doesnt sound silly at all because it is often the little things that cause big problems. Open to all suggestions

[ls1nova71]

You're using the neutral safety switch that came with the 5.3 and is mounted on the side of the transmission? It might just be out of adjustment. Have you tried cranking it while moving the shifter (with your foot on the brake and the wheels chocked)?

[afcamaro]

Yes it is on the side of the transmission. I have it adjusted to park, but will play with it as well and see what happens.

[joesgreen67]

Any updates?

[afcamaro]

Im sorry Ive been super busy this week. Im gonna try messing with the shifter tonight and see what I come up with. Thanks

[ls1nova71]

One other thing to check is the plug on the neutral safety switch, make sure it's plugged in all the way. The factory puts some kind of glue on the plugs that makes them hard to remove and install. Also pulling on them trying to get them out, since they're glued in, will sometimes break a wire in the insulation, you won't be able to see it, but it won't have continuity.

[afcamaro]

Alright thanks for the replies, but no luck on the shifter messing with. Ill check that plug. Is there anything else to check for the neutral safety switch? Its just that plug on the trans right....nothing else needed as far as the neutral safety switch is conerned?

[ls1nova71]

Originally Posted by afcamaro

Is there anything else to check for the neutral safety switch? Its just that plug on the trans right....nothing else needed as far as the neutral safety switch is conerned?

There is also a starter relay, you can check it to see if it's getting power. Also you can take the relay out and jump the #30 and #87 terminals in the relay plug and see if it cranks, it should. If you do this MAKE SURE THE TRUCK IS IN PARK AND THE WHEELS ARE BLOCKED since you'll be bypassing the NSS.

[afcamaro]

Ok I checked the connection at the trans and it seems to be good. The relay does have power to it (test light on #30) and I jumped the relay as well and it tried kicking the starter over immediately(but without turning the key ignition, idk if that's normal). Thanks

[ls1nova71]

Ok, if jumping the plug cranked the engine over then that part of the circuit is good. Your problem is going to be on the other side of the relay, the 85 and 86 terminals. One of them will have power when you crank it the other will be ground. Chech to see if you have power in the crank position by putting a test light on it and have someone turn the key to crank. Also check to see that the other side has a good ground.
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[BR3W CITY]

I might be reading semantics too much, but I got that the starter was turning over, not the engine. Just to be clear, did the engine crank, or did you just hear the starter spin/whine? I had a starter problem (seemed like a dead battery scenario), and found it to be nothing more than a tad of corrosion. I'll add it to the list of "stupid silly stuff that boggles me", I had bought a premium brand new starter, and upon install thought I had a battery or short or charging system issue because it was acting like it had no power. In actuality, it had power, but the starter had sat on the cold wet floor in its box for too long, and corroded slightly inside. I whacked it with a sledgehammer, problem solved.



I did go exchange it as defective just because I could, but you'd be surprised what a sledgehammer can fix these days. (in my life, starter, alt, dizzy, wheel, ball joint, fender....and an argument. Have all been solved with a sledge, go figure.)

[afcamaro]

Alright I checked the #86 and #85 terminals with someone cranking the engine. No power. I will check the ground, but the ground should be coming out the back of the relay correct, and the grounded near the relay box's?

[ls1nova71]

Originally Posted by afcamaro

Alright I checked the #86 and #85 terminals with someone cranking the engine. No power. I will check the ground, but the ground should be coming out the back of the relay correct, and the grounded near the relay box's?

Not sure where someone would put the ground on a modified harness, but yes it should come out of the back of the relay. But since you don't have power when cranking, we'll assume for the time being that the ground is ok.

First, back to basics. Do you have a factory '72 NSS mounted on your column?

What year of harness are you working with?

The purple wire that originally went to your starter, what did you hook it to? Should be hooked to a pink wire going to the NSS on the side of the transmission, if it's a '99-04 ( I think it was '04 that was the last year for the 2 plug NSS) it will be #12, '05-'07 have a single plug NSS and will be at position E. You'll need to unhook the plug and check for power at that terminal while someone turns the ignition to "crank"

[afcamaro]

To the best of my knowledge I have a '70 truck harness on the column. I never messed with that but the cabs a 70. The engine harness is out of an 04 Sierra. Ill check the routing of the nss when I get home and the purple wire to the starter.