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1975 corvette
So I'm running a standalone wire harness but I need to find a wire that will stay powered on as the car is cranking. Can anyone help with that?
Just FYI.... methinks the IGN is active in both Start AND Run...... in case that matters to you.....
Originally Posted by DragonZ06
1975 corvette
So I'm running a standalone wire harness but I need to find a wire that will stay powered on as the car is cranking. Can anyone help with that?
Just FYI.... methinks the IGN is active in both Start AND Run...... in case that matters to you.....
Not true-
You have acc and ignition - wipers /radio- that is NOT hot in starting
and
not hot in ACC but in ignition and start ( gauges)
If doing a standalone ignition- I would use a relay switched to control the ECU- rather than a "dirty" wire off the fusebox.
The ECUs don't like dirty power/grounds and voltage drops and could cause issues.
Thank you for replying. After I read this post I went back out to the car and noticed a red 12 gauge wire that had been hooked up to the original distributor, so I think I have it figured out. I am going to have my neighbor help me check it tomorrow before I hook it up and possibly blow//pop something if its not.
Thanks for replying. I will keep the post in case things change.
You have acc and ignition - wipers /radio- that is NOT hot in starting
and
not hot in ACC but in ignition and start ( gauges)
If doing a standalone ignition- I would use a relay switched to control the ECU- rather than a "dirty" wire off the fusebox.
The ECUs don't like dirty power/grounds and voltage drops and could cause issues.
Richard
Last edited by carriljc; Jul 26, 2024 at 06:35 PM.
Having just installed a Sniper 2 I was using the ING for cranking voltage. After installing the Sniper it reported back that my voltage was dropping to around 8 volts intermittently. Did some research and found someone stating that this input is the input that is displayed on the Holley handheld. I wired it directly to the ING out of the fuse box. Then I installed a Bosh relay and the noise was still there. This is where the confusing started as others stated the ECU main power should be wired directly to the battery. I had mine wired through a fuse box I installed. While troubleshooting I jumpered in power and ground from the Sniper main power/ground directly to the battery and my voltage is a steady 13.5 volts. So for all that is going Sniper EFI the voltage reported on the handheld is MAIN VOLTAGE not cranking or ING voltage.
With all that said unless the ING is really noisy and has voltage drops it should do what it needs to do during cranking without a relay but a relay does solve a lot of issues.
I'll check my wiring to see where I attached my relay for components that need power during START & RUN. Initially I ran a couple of components directly from there but later I also installed a relay and got power from the Horn Relay Bus Bar..... now the voltage indicated on my EZ-EFI is really close to battery terminal voltage now. AND yes my EZ-EFI is directly connected to the Battery.
Originally Posted by theandies
Having just installed a Sniper 2 I was using the ING for cranking voltage. After installing the Sniper it reported back that my voltage was dropping to around 8 volts intermittently. Did some research and found someone stating that this input is the input that is displayed on the Holley handheld. I wired it directly to the ING out of the fuse box. Then I installed a Bosh relay and the noise was still there. This is where the confusing started as others stated the ECU main power should be wired directly to the battery. I had mine wired through a fuse box I installed. While troubleshooting I jumpered in power and ground from the Sniper main power/ground directly to the battery and my voltage is a steady 13.5 volts. So for all that is going Sniper EFI the voltage reported on the handheld is MAIN VOLTAGE not cranking or ING voltage.
With all that said unless the ING is really noisy and has voltage drops it should do what it needs to do during cranking without a relay but a relay does solve a lot of issues.
You have acc and ignition - wipers /radio- that is NOT hot in starting
and
not hot in ACC but in ignition and start ( gauges)
If doing a standalone ignition- I would use a relay switched to control the ECU- rather than a "dirty" wire off the fusebox.
The ECUs don't like dirty power/grounds and voltage drops and could cause issues.
Richard
Are you sure about that? Myself (and many others, I believe, have replaced factory points dizzy with an HEI, and wired it to the IGN terminal on the fuse panel. If it isn’t live in start or run, the HEI wouldn’t work in either position.
I *think* IGN is powered up in START and RUN but I am not going to disagree with Richard454 until I verify.
Once I check i will state what I find.
He is usually fairly accurate so I have to check myself.
Originally Posted by wwiiavfan
Are you sure about that? Myself (and many others, I believe, have replaced factory points dizzy with an HEI, and wired it to the IGN terminal on the fuse panel. If it isn’t live in start or run, the HEI wouldn’t work in either position.
"I *think* IGN is powered up in START and RUN but I am not going to disagree with Richard454 until I verify."
Sorry- I was not saying the "ign" on the fuse box was not hot in start-
To clarify-
The are numerous threads where somebody has used the yellow for wipers- that is Hot during ignition - but not during start.
But I am saying- just because the wire is HOT during ignition does NOT mean it will be hot during cranking..
AND when you are adding aftermarket things to these cars that were designed over 60 years ago- when dirty power was not an issue-
It will require some thought to add on correctly- going directly to the battery and using relays is the cheapest and easiest to help keep electrical gremlins at bay.
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Need to find a live wire while in Crack position
