PUNISHER VETTE

Okay. Sorry if a lot of this seems basic but I'm new to wiring and i'm getting super confused. LS1 into a '69 vette.

Trying to figure out what wires from the old harness need to still get hooked up along with the new LS1 wiring harness.

1. The picture from PSI harness only had 1 wire hooking up to the starter yet I have two...not sure if one is a motor ground? or if both hook to the large post on the starter solenoid.
(they are the two in my hand)

-From the old harness I'm showing the two large connectors and two small. I'm diving into my wiring diagram to figure them all out. Pretty sure my old solenoid had 4 posts and each one went to a different post. Not sure which ones are needed now that I only have 2 usable posts.

garys 68

iTrader: (1)

Your old starter had a post from the solenoid that energized the coil with a full 12 V during cranking, it bypassed the ballast resistor. You dont need that with the LS motor.

PUNISHER VETTE

Thanks.


Yeah. I just traced back wires on my diagram and have figured out the old harness!

large red= hook up to solenoid..it goes to horn rely and eventually to ignition

large black=engine ground. might as well hook up to block.

small black= wire that went to the old coil. Leaving unhooked.

small purple= wire that goes to ignition/clutch synchro/neutral safety swith. I hooked it up to the small post on the solenoid.

BUT
I'm even more worried about the two connections from the new harness.
I was going to put them both on the large post but that means constant power all the time right?

The only two large red wires going into the fuse panel are:
-10amp fuse giving constant power to PCM
-Igntion relay which says should be switched

if they are both hooked to the large post they are both constant power right?

PUNISHER VETTE

Here is a picture off PSI's website that looks like they just updated for the new harness with 2 connections.

As you can see they have two connection labeled for the starter BUT they have one that is obviously much smaller. I'm wondering if they screwed mine up and I should have one small one for the switched ignition relay to the small post on the solenoid?

garys 68

iTrader: (1)

I hate to tell you this, but with an early corvette with the ammeter it's more complicated.
If you want the original dash to work correctly, hook the constant hot up to the horn relay distribution point.. Wait, it gets worse...
Early corvettes have an ignition that only provides voltage to the coil when in run. When cranking, coil voltage is provided by the starter solenoid bypass wire. You'll need to check your ignition for a hot lead when cranking and in run. That wire goes to the "hot in run" leads.

PUNISHER VETTE

I'm pretty sure how I have it hooked up now should work. Only wire that I'm not using is the one that used to go to the coil. Purple is still a switched wire and red is still a constant so nothing changes there.

My biggest concern now is why they sent me two of the large terminals when I'm pretty sure one needs to be tiny to be on the switched post.

74modified

Purple at starter is switched on when key is turned to start (energize the starter), when you let the key back to run position it is off. You need a power on in run postion.

PUNISHER VETTE

lol. How do you guys keep up with so many forums? Or are you stalking me?

I need to do some searching I think. Everywhere I look it's showing the purple wire goes at the top small post...

Stolen from a C5 corvette post.

74modified

You can run but you cannot hide... LOL
Yes it goes on the small starter lug, but you cannot get your hot in run power there for the rest of the wiring

PUNISHER VETTE

But...but...but....

If the purple is the same all that is left is the large red from the old harness which should be constant power right?

was the coil supplying power to the run accessories? That's the only different post i'm missing...
Maybe the horn rely controlled the run power to the stuff that needed it?

74modified

I think that was what Gary was saying. The purple is hot with key in start. The big red is hot all the time. You need one that is hot in start and run, and I think that is hard on a 69

74modified

This may be a way. No guaranty
http://www.trifive.com/forums/archiv...p/t-11431.html

Edit - or maybe not. This could be a 68 back problem. You need a meter or test light and someone to turn the key while you find a circuit that is hot in both run and start.

PUNISHER VETTE

I guess I'm not sure why I need "hot in run" stuff? the PCM looks to need constant... everything else is switched through the ignition.

I don't see anywhere that I need to give "hot in run" power to in the new fuse box...

Only the two wires here are what I was planning on adding...
1 fuel pump, 2 constant power...for some reason that they couldn't get from the solenoid...

74modified

I know this is a pain, but look at the picture. It says switched must be on in run. (run position on the key) You have to find a curcuit that is hot in run & start. IF your ingnition is hot in BOTH you are good.

PUNISHER VETTE

I guess I'll call PSI one of these days when I'm free as I'm still super confused.

I assume one of the two terminals they have in the photo below goes to an "ignition/run" post on certain solenoids? ...but NOT the stock LS1 solenoid...since it only had constant and start.

Everything else in the harness is already pre-wired so to get "run" power it has to be through one of the connections they provided.

LS1MCSS

iTrader: (18)

The reason they are saying that a certain wire has to be hot in run and start is, itthe motor won't start if it's not that way. A wire may be hot in the run position of the switch and lose power when you go into the start position. If it does that, the car will NEVER START. I see you are confused about the term "hot in run". Hot in run and switched power are the exact same thing.

PUNISHER VETTE

I guess I'm confused that my old wiring never used "run" power and the new pre-wired harness is for a stock LS1 and it isn't set up for finding run power so...

I see switched as off when key is off, on when key is on.
It's been a long day, maybe it'll hit me some other day.

psiconversion

iTrader: (5)

Wow I don't scour the board 1 day

To answer your question, we have updated the picture in the instructions to show both Large Ring terminals (that you have a question about) go to CONSTANT POWER. Typically this is the large lug of your starter motor since that is where your battery cable is hooked to.

Regarding the starter motor wiring (to crank the engine). This must be supplied by the vehicle you are putting the engine in. Typically it consists of a purple wire from your ignition key and another constant power wire that feeds your fuse box in the vehicle. Hope this helps, if not give us a call when you have time, 732-691-6531. Thanks.

Jon
PSI

PUNISHER VETTE

Awesome! I didn't know you guys were members lol.

The updated picture helped a lot when I saw that but the two large terminals made me worried so that's good they both go to constant(as I already hooked them up that way and don't want to crawl under there again lol)

But yeah, the build quality of the harness so far has been great. I wish I set it up to go into the drivers side of the engine bay but ended up having enough length and it still looked decent the way I routed it.
I had to extend my O2 sensor plugs since I'm running sidepipes but that was unavoidable since they weren't even bought/built yet when I ordered the harness.