12v switched source for red and white wire on Terminator EFI

[Chevelle489efi]

I cant find a good 12v source. The one I found has 12v switch on and 9.75 while engine cranking will that still trigger relay to turn fuel pump on?

[wayward]

does your voltage drop if you measure directly at the battery when you are cranking the engine?

[Chevelle489efi]

No. at the switched source fuse box under dash.

[shep]

9 volts should trigger the relay.

[Chevelle489efi]

The source puts out 13 plus when it goes backs to on after starting. just worried because the trigger wire is triggering another relay that runs fue pump and first relay runs injectors. So if it triggers the relay will relay put out 12v to injectors an next relay?

[Derek@ModernSpeed]

The switched 12V wire is not directly associated with the relay on the main harness. That wire provides 12V to the ecu, and in some cases the ignition connector.

[Chevelle489efi]

Any suggestions were to hook up or is 9v good enough during cranking? thanks

[Chevelle489efi]

If I can not find a constant 12 v source can I hook the red and white wire to battery and install a toggle switch to turn on when I start and leave on to provide the 12v's

[wayward]

My suggestion would be to understand why it drops to 9 volts.. Not to be a smart a$$. But...

That seems like an extreme drop and I would want to verify 1. if that were normal, 2. all my electrical connections were tight and secure. ( If they are loose they create resistance/heat and can cause a fire) 3. I don't have a weak cell in my battery.

If you feel comfortable with all that:
before I ran a separate switch I would set up something temporary and test to see if it works. I would image if the drop is just during cranking you would be fine. The pump runs for a few seconds when the key is turned on. That should give you the appropriate pressure and worst case scenario it would function at full yield after the engine starts.

[Chevelle489efi]

Will check all that this weekend Thanks.

[wayward]

I. Just read dj94qt response from yesterday. Sounds like you are on the wrong wires.

I haven't hooked up my holley yet so I don't know.

Message regal454, he has one running and I helped him with some of the hookup but don't remember what we did. His name is Marc and would be happy to help..

[Derek@ModernSpeed]

Wayward is on the right path. If you have 13V+, and it drags down to 9V when cranking, that issue needs to be addressed before hooking up the Holley the rest of the way. They system works great, but it can get really funky when voltage drops below 10.8. As for the idea of adding an interrupt switch, I'd scratch that idea and fix the voltage drop issue.

[astroracer]

The relays #87 terminals SHOULD be hooked directly to a 12v distribution block for "running" voltage. I run my relays backwards (terminal 87 is "in" voltage, terminal 30 is "out" voltage) Using terminal 86 as the switched source this voltage can be very minimal to turn on the relay. All the switched source is doing is turning on the relay. The actual 12volts will come through terminal 87 from the 12v distribution block. Wire a good distribution block directly from the Batt Terminal on the alternator to the firewall and make sure you are using fuses. The relay will remain "on" as long as the key is in the run position.
Mark

[wayward]

The relays #87 terminals SHOULD be hooked directly to a 12v distribution block for "running" voltage. I run my relays backwards (terminal 87 is "in" voltage, terminal 30 is "out" voltage) Using terminal 86 as the switched source this voltage can be very minimal to turn on the relay. All the switched source is doing is turning on the relay. The actual 12volts will come through terminal 87 from the 12v distribution block. Wire a good distribution block directly from the Batt Terminal on the alternator to the firewall and make sure you are using fuses. The relay will remain "on" as long as the key is in the run position.
Mark

I would also highly recommend running relays as described to any item that draws any "measurable" current...

Great input...

[Derek@ModernSpeed]

Ok, so I pulled up a print to make sure I'm on the same page as you. According to the blueprint of the main harness for Terminator systems, the switched 12V wire has nothing to do with the relay in the system. This red/white wire provides power to the ecu (pin A10), and power to the Ignition connector (location E). The solid red wire (from relay on harness) should go directly to the battery. So this is what I see.

Solid red goes from the battery to 87 terminal on relay
ECU pin A2 sends the "trigger" to relay on terminal 86
Relay terminal 85 is the ground (loose wire), and also goes to pin (D) on the ignition connector
Relay terminal 30 is the 12V output to the fuel pump (loose green wire), and pin (A) on the ignition connector

Relay is not connected to the red/white 12V trigger wire. Address the voltage drop issue, and hook the red/white wire up to the fuse panel so that it has power in the crank and run position. As long as it keeps 10.8V, the system should be happy. Anything less will strain the digital components inside the ecu. Make sure all constant power/grounds go to the battery. Clean power/ground is a necessity. Distribution blocks, and bus bars are not clean sources.

[wayward]

Should the fuel pump be on a relay, or is the ecu designed to handle?

I'll pull my docs out and look as well... you can teach us both... :-)

[Derek@ModernSpeed]

The relay on the main harness has a loose green wire to provide 12v to a fuel pump. However I think it's rated up to 10-15amps. If a high flow race style pump is used, another relay should be used and the green wire would be used as the trigger for the 2nd relay

[Chevelle489efi]

Nothing worked. Redone all connection, new battery, trying voltage stabilizer next thanks for all your help

[wayward]

voltage still drops ? measure the voltage directly on the battery when you are cranking...

is the motor a high compression motor?

voltage stabilizer ??? are you talking about a large capacitor?

[Chevelle489efi]

Yes to all.

[wayward]

I downloaded the wiring diagrams for the Holley and started laying out my harness today. So I guess I could be a little more help now...

If you have known good battery, power and ground connections, and verified and your whole system voltage is dragging down, I would attempt to make sure you can explain the voltage drop prior to rectifying the symptom... Typically voltage drops are created by resistance or lack of capacity. The voltage drop will automatically increase your amperage draw and that is what will damage the electronics.

Do you have 1Gauge cables or larger on the power and ground connections?

When you feel comfortable with all that I think the capacitor would be a sound resolution. This would also help clean up the power of other items as well...

good luck, if I can help let me know...
EL

[Chevelle489efi]

Got it up to 10.67 during cranking, battery was at 12.45 ten i figure after full charge at 12.8 it will be 11v

[wayward]

Sounds like your working toward the right solution...


In accordance with dj94rt the holly tech rep. Keep the voltage above 10.8 vdc to ensure consistence performance of the ecu..

For my future wiring what did you do to get the voltage up?

I would imaging a drop of 1-1.5 vdc would be normal.. Although this is just a guess, I'm sure someone here know the exact tolerance..

[Chevelle489efi]

replace all the grounds and install three earth grounds. Battery to engine, battery to fame and engine to frame.

[wayward]

I personally would proceed and keep it in mind if its a little flaky...
I buy your theory on the 11vdc is very possiable... you will definatly get some drop when cranking.


Might want to reach out to dj94rt just to verify. But it sounds like you have done a good job and have a solid baseline to work from...

[Chevelle489efi]

Got it running with 9,7 volts during cranking and works fine.

[Robrich342]

Hey Chevelle , where exactly did you hook your red and wire up to? and how if it required anything special.

Thanks Rob

[dhutton]

Hey Chevelle , where exactly did you hook your red and wire up to? and how if it required anything special.

Thanks Rob
On a GM car you can hook the red and white wire to any pink wire. The current is low, it’s only used to sense ignition on.


Don