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Hey guys and gals, I'm having trouble with my Ls1 powered Nova. It's a new build and I'm working out the bugs. I drove the car about 400 miles (mostly highway ) before the problem surfaced.
The 1st time it happened, I drove about an hour (15 min. Back roads, 45 min. Highway) slowed down and stopped in traffic ,then my gauges started to flicker and shut off . My engine ran for about 30 sec. more before it shut off. I saw some smoke come out from under the hood. I 1st thought my horn relay fried but it turned out to be the power wire that comes out of the horn relay and powers the fuse box. I replaced the horn relay (just because) and replaced the melted wire. Now when I dive the car for a 1/2 hour or so my gauges start to flicker , and the engine stumbles. My electric fan relay will click on and off and I can see the voltage randomly drops down to 9.5 or 10 for a split second.
Now this other issue I've had since day 1 of the new build .It may not be related but maybe it is.... when I turn the key to start the engine, I release the key but the starter continues to crank for a sec. Or 2. Also when I turn the key off it takes between 1 to 4 sec. To shut off.
I have the battery in the trunk with a "ford" style solenoid also mounted in the trunk with a small jumper wire on the starter. This is how I have it wired :
Any ideas or suggestions would be greatly appreciated. 2 trips home on a flatbed is enough...
My specs:
70 Nova
1999 LS1
Holly EFI HP system w/ 3.5 touch screen
75mm single turbo
manual 4L80E
I would look at the ignition switch because of the cranking and shut off delays. Is the key in dash on on the column? In dash, just get a new GM switch (knock-off) and see if your problem goes away. Same if it's column mounted, just replace the terminal at the bottom of the column.
I changed the switch that mounts further down on the top of the column, but I have not changed out the key ignition switch.... Do u think it is related to my voltage issue?
No, the key on the column only operates the rod that goes to that switch. Make sure that the rod moves smoothly as you turn the key. Also do some research on how to adjust that rod/switch. You may have fried SOME of your alternator. During normal driving what does the voltmeter read? Have you had the alternator tested?
I used to have that wire on my Nova fry that wire on the horn relay too. It is the main power source for the whole car. I ended up bypassing it when I did my LS swap and its been fine since. As for the starter hanging for a second, that is because of the Ford starter relay, and they're known for doing that. On my LTD wagon I tried to use it and put the small jumper wire on the starter and it always would keep the starter engaged for a second. I wired it like a GM and didnt use the Ford relay and it fixed it. A lot of mustang swaps have had the same issue.
One other thing, how do you have your fans wired? You need the main power for them wired direct to either the battery or alternator and not from the wire that comes from the horn relay, since they draw way too many amps to use that small of a wire.
As far as how i wired the fans . I know I used a single high amp relay . I ran it to a term post that's powered by the battery when the key is on. But let me say this, when the issue was occurring I disconnected the power to the fans and there was no change....
is there a way I can post a 30 sec. Video of my 3.5 Holley display when the problem happening? I know I can send it through Facebook.
I have mine wired just like your except I have my Ford relay under the hood. I have no problems with the starter staying engaged. Maybe I am just lucky because I was told the same thing that it would hang up using that arrangement.
you'll want to check voltage at the battery, at the junction box, and at the alternator output, with load off and load on. a voltage drop along any of those routes can help you better locate the problem.
I had similar issues, albeit not nearly as bad, and ran an small wire forward from the battery to test the voltages (hat tip to -TheBandit- for the idea). this can help determine if you're having ground issues. you should have a few tied between the engine block, front subframe and body.
finally, if you're using that diagram for your wiring, note that 8ga wire is only good to about 50-60 amps at the length run from the trunk. you should use 4ga for both the alternator and power distribution, as the added electrics with an LS can quickly add up (for example, my taurus fan pulls 36 amps on high).
[QUOTE=hookemdevils22;19677546]
ran an small wire forward from the battery to test the voltages (hat tip to -TheBandit- for the idea). this can help determine if you're having ground issues. you should have a few tied between the engine block, front subframe and body.
can you explain that differently? Im not totally understanding... Did u run a ground wire forward from the battery?
Last edited by Popsnova; Jul 17, 2017 at 07:07 PM.
Alright, just went out , ran the car up the street and back , let it idle for a while , shut it off let it build some heat . started it back up , let it idle some more .It got pretty hot. But i couldn't duplicate the problem..... I did however take some voltage readings . With the car running, I put a volt meter between ground and the starter solenoid (in trunk) where the wire from the alternator attaches to charge the battery. It read 13.15V max @ 1000 rpm.
Then I hooked up another volt meter up front on a ground and the alternator hot post. It read 14.00V max @ 1000 rpm. That means im losing around .85 of a volt from front to back right?
Would you guys say that the charging wire (8awg) is too small for my set up?
When I built the setup I spoke to the Electrical guru at M.A.D Electronics he told me 8 awg will be plenty , but Im not sure he was aware of the fact that I have an LS with computer , fans , radio etc...
I used this info:
"If the battery is relocated to the rear using rear mounted starter solenoid system, then the battery charging wire will be much longer. In that case we recommend twelve to twenty feet of 8gauge battery charging wire with a 12gauge fusible link at the rear. (Preference for length is with about eighteen feet of the 8gauge charging wire."
What do you all think?
Last edited by Popsnova; Jul 20, 2017 at 03:55 PM.
8ga is only good to about 60amps at 10'. I doubt that's your issue, however. What is your battery grounded to? You should run a dedicated bit of wire to the battery ground to check your voltages, and see if that's the issue.
For sanity's sake, you might want to double-check your wiring at the new horn relay, or the new relay itself (I don't know how it's wired, since I rewired mine long ago). Either your wire initially melted due to age or current exceeding its capacity. The latter is entirely possible if you're running your Holley/LS electronics off the same wire as your body/lighting. Just for giggles, check voltage at the fuse box input from the horn relay. I'm also hoping you have a dedicated feed for your fan relay(s).
And about the video: you can upload it to Youtube and embed it here by copy/pasting the link.
Make sure you have a ground strap from engine to body / frame. Engine, tranny, rear end, and exhaust system are all mounted in rubber and you must provide good grounds. I've seen cars that were only grounded with the throttle cable and E brake cables. Not good enough.
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Voltage drop issue 
