Quick help on current performance harness, trying to start

[68c20lwb]

Hello, I am trying to start my 5.3 on the engine stand in the garage. I have been struggling with this for a little while and I am stumped. I hooked up my battery negative to ground on block, battery positive to starter. I then touched my yellow/black (cranking signal) to positive and nothing. I then touched my pink/black (12V switched) and heard a relay click. I then touched both to the positive and nothing other then the relay click. I jumped my starter with a screwdriver to turn the engine over and check oil pressure, that was no problem. With my battery connections I should be able to touch my standing signal to positive and the engine should turn over correct? Am I missing something obvious here? All fuses are good, all grounds connected.

2005 5.3 everything original to the truck. Current Performance harness, speartech tune.

Thank you,

August

[BR3W CITY]

Do you have a grounding block in use for the engine grounds? Just the batter terminals prob won't be enough to run, these efi engines are very sensitive to grounding and current loss.

[68c20lwb]

No I do not have one, good suggestion. Any idea how to wire that?

[BR3W CITY]

I've never run an engine on an engine stand, unless it was actually a wet-stand like you'd find in a dyno room. Thats the thing that usually has a little fuel and coolant tank etc to do full hookups. On many of those, there is a nice big chunk/surface with with a bolt, and it ties to the rest of the body. The hard mounts on the stand technically should do the grounding for the block and/or heads, but using the ground point you can hookup the starter/frame grounds and the battery ground as well. If you look at the battery mounting point on engine dyno's sometimes you'll see pre-drilled spots to pop a bolt thru to ground. Same with on the carriage/stand (as well as the internal grounds on the harness)

In a pinch you could probably just ground it to the stand, but you can also take a heavy piece of scrap and put a bolt thru it, then bolt or tac it to the stand. On the same accord, you might want to look at just trying a small ground on the ecm case itself (the internal ground can fail, and grounding the case will help with errors or sporadic electrical failure).

When you jumpstarted with the screwdriver, did the engine run? With the engine outside the car, certain things might be harder to troubleshoot. So right now, is the engine plugged in with ecm and all that stand-alone on the stand?

[68c20lwb]

Everything was plugged in on the engine. I didn't have fuel to the engine yet because I wanted to turn the engine over with the harness to confirm proper operation. When I jumped the starter I had neither of the 2 wires connected. So I cannot say if it would have ran or not. I will have to try grounding out the system to the stand somehow and try that if I get a chance this week. I hope this could work. Here I am doing an LS swap and know less about wires then a newborn baby (exaggeration). Thus the reason for paying for a harness modification. I will try that as soon as possible and get back to you. Any other thoughts in the meantime?

Thanks,

August

[ls1nova71]

Originally Posted by 68c20lwb

Hello, I am trying to start my 5.3 on the engine stand in the garage. I have been struggling with this for a little while and I am stumped. I hooked up my battery negative to ground on block, battery positive to starter. I then touched my yellow/black (cranking signal) to positive and nothing. I then touched my pink/black (12V switched) and heard a relay click. I then touched both to the positive and nothing other then the relay click. I jumped my starter with a screwdriver to turn the engine over and check oil pressure, that was no problem. With my battery connections I should be able to touch my standing signal to positive and the engine should turn over correct? Am I missing something obvious here? All fuses are good, all grounds connected.

2005 5.3 everything original to the truck. Current Performance harness, speartech tune.

Thank you,

August

I always start my engines on the garage floor anymore just to make sure they run and never had a problem. I do it real ghetto too, with all the pink and orange wires tied together and clamped to a battery with vicegrips. No special grounding is necessary as long as all your harness grounds are hooked up.

That said, I'm not familiar with the current performance harness, but most stand alone harnesses don't have starter wires in them. Does yours have a starter relay built into it? If it does, and your engine is on a stand, my guess is there is no transmission hooked to it and therefore no neutral safety switch hooked up. With the NSS unhooked it won't crank.

[68c20lwb]

I am not positive about the starter relay, I do not believe it does, I will check on that. I thought it might be something stupid like a NSS, I will hook that up and try. I am starting for the same reason you are, to check and make sure everything is in proper operational condition. Sounds like we ghetto rig it the same way as well. Hey, by the way, you have any ribbed cruise control switches?

[dec010974]

If current performance hasn't changed there relay boxes, the relay box has the following, (9) fused power circuits, (2) fan relays, (1) starter relay, (1) ignition relay, (1) fuel pump relay, & (1) a/c clutch relay. If I said it once, I said it a hundred times, not to, speak bad about current performance, they wire their relays different. When I used there relay box, I rewired the relay box to a standard fashion, to run my LSx swap. I'm not saying that's the problem but it may lead you to solving ur wiring problem. To give you an example, 87-sends power to all my accessories . CP- 87 is fused battery power. batteryTo get a consensus, how do everyone wire their relays? I'll revisit this thread to see if we can help another brotha' get his LSx swap going. Good luck.

[68c20lwb]

I guess I'm not familiar with how to wire relays and different ways to wire them, I just thought there was only one way. I checked my box and you are correct, that is how the box is set up with the relays and fuses. I hope we can get this figured out I am very motivated to get this going with the now warmer weather and the fact that my 350 is getting awfully tired. Thanks for the help and let's keep this going!

[ls1nova71]

Originally Posted by 68c20lwb

I am not positive about the starter relay, I do not believe it does, I will check on that. I thought it might be something stupid like a NSS, I will hook that up and try. I am starting for the same reason you are, to check and make sure everything is in proper operational condition. Sounds like we ghetto rig it the same way as well. Hey, by the way, you have any ribbed cruise control switches?

Oh, I don't think you're even close to as ghetto fabulous as mine, you have a fuse box. I start them so I know they'll run, but also to satisfy the little kid in me that gets a thrill from seeing an engine run sitting on the garage floor.

As for the ribbed cruise levers, I don't have any at the moment, and not sure if or when I will have any more. The ribbed part comes from a somewhat obscure early '90's GM car, and I haven't seen any in the junk yards lately. The smooth one I still have.

Heres a video so you can see my redneck ingenuity at it's finest! The video is a little shaky, so you might get sea sick watching it, but it's because I was working alone.....

Originally Posted by dec010974

If current performance hasn't changed there relay boxes, the relay box has the following, (9) fused power circuits, (2) fan relays, (1) starter relay, (1) ignition relay, (1) fuel pump relay, & (1) a/c clutch relay. If I said it once, I said it a hundred times, not to, speak bad about current performance, they wire their relays different. When I used there relay box, I rewired the relay box to a standard fashion, to run my LSx swap. I'm not saying that's the problem but it may lead you to solving ur wiring problem. To give you an example, 87-sends power to all my accessories . CP- 87 is fused battery power. batteryTo get a consensus, how do everyone wire their relays? I'll revisit this thread to see if we can help another brotha' get his LSx swap going. Good luck.

I usually use 30 as power and 87 as power out, but if you're not using the relay to switch back and forth from 87 and 87a, it really doesn't matter. But their way does seem kind of backwards.

[68c20lwb]

You absolutely got me beat on ghetto rig for sure. I'd probably take a smooth one. Does the way they wire the relay really matter? I mean they produce them this way for a reason right?

[First c10]

Originally Posted by 68c20lwb

Hello, I am trying to start my 5.3 on the engine stand in the garage. I have been struggling with this for a little while and I am stumped. I hooked up my battery negative to ground on block, battery positive to starter. I then touched my yellow/black (cranking signal) to positive and nothing. I then touched my pink/black (12V switched) and heard a relay click. I then touched both to the positive and nothing other then the relay click. I jumped my starter with a screwdriver to turn the engine over and check oil pressure, that was no problem. With my battery connections I should be able to touch my standing signal to positive and the engine should turn over correct? Am I missing something obvious here? All fuses are good, all grounds connected.

2005 5.3 everything original to the truck. Current Performance harness, speartech tune.

Thank you,

August

My 5.3 had a purple wire from the solenoid and so did the original 1970 starter wire to the original solenoid. Did you add the yellow/black wire?
before I buttoned up my wiring I just spliced all the power wires and the ground and clamped them to the battery touched my purple wire to the battery and she started right up! it was ghetto as some would say, except it was sitting in the truck

[68c20lwb]

Well I set the trans on the ground next to the motor, strung the battery negative to block to trans. Plugged in the trans connectors. Battery positive to starter. Now I hear a relay click when I touch crank signal to positive. That didn't happen before. So relay click with crank signal touched, relay click with 12V switched touched, and both click when both touched. Nothing more. Still no crank. No codes on the system. All I changed was hooking up trans connections and grounding trans case. What next fellas?

[68c20lwb]

First C10, my yellow/black and pink/black came with the harness I had modified by Current Performance. Yellow/black is labeled cranking signal.

[dec010974]

Are you using a stock harness or a current performance harness? If you are using a current performance harness, call Jared, the owner and ask him to help u trouble shoot. I'm sure he's a wizard with his own harness. I used his relay block for a past LSx swap. I couldn't get the relay box to work so, I rewired the box my way and voila, I was LSxified. The clicking in the relays are a good sign. Now u gotta get the power to the right sources. Call me if u need help
305-815-6660. Clark.

[First c10]

Does the yellow/black come from the ignition switch? on my harness which I re worked from the stock harness does not include the starter solenoid wire. The motor package had the wire(purple wire with a special connector that plugged into the starter solenoid) that I connected to my current purple wire on the 70 stock harness.

[68c20lwb]

I had the stock harness modified by current performance, so it is now a current performance harness. I wish I knew how more about wiring and maybe I would re-wire the relays myself if that seems to be the problem.

FirstC10, my engine in in the garage, not in the truck, so there is no ignition switch. Just the wires coming off the harness. Yellow/black labeled cranking signal, and pink/black labeled 12V switched. On the current performance harness there is a wire that goes to the smallest terminal on the starter, unsure of color as it is covered.

[dec010974]

68c20lwb, just get a direction of where you're going, if possible, when everything is connected, even the relay box, can you use a test light and see if you have power to the coils, injectors, maf sensor, tranny, tac module, if you have one, etc? If you have power to all the following, that will be a start. Call me and I'll be able to go wire by wire. My relay box is not in use. But I have the wiring schematics cp uses to assist you with your LSx. Clark

[ls1nova71]

Originally Posted by 68c20lwb

Well I set the trans on the ground next to the motor, strung the battery negative to block to trans. Plugged in the trans connectors. Battery positive to starter. Now I hear a relay click when I touch crank signal to positive. That didn't happen before. So relay click with crank signal touched, relay click with 12V switched touched, and both click when both touched. Nothing more. Still no crank. No codes on the system. All I changed was hooking up trans connections and grounding trans case. What next fellas?

Are the relays labeled at all? I'm guessing not. The relay that clicks when power is put on the wire labeled cranking signal, you could try taking it out and jumping the terminals 87 and 30, if it doesn't crank then, you've got power to one terminal on the relay, the one that powers the relay, but not the one that powers the starter side.

[dec010974]

Ls1nova71-side note: do you need some assistance? I assume you're you getting ready to start your blazer build, right? I can sell my truck, to fund your blazer build. Lol. I could use a good story line. "The walking dead," is off, the nfl season wont be here until September, and " fast n loud" is showing repeats. Just say the word, I'm all eyes and the 1971 c10 is gone. I'm sure my wife would like that. Your builds threads makes me appreciate teachers. They teach us to read. Also, you can use my garage.

[68c20lwb]

Okay, I just jumped 30 and 87 on the starter relay (cranking signal) and no crank. So I have power into the relay, but not out, correct? What does this mean?