Mac's Car Refresh

Mac said:
Lots of work this weekend. Got the engine harness married with the computer harness. Checked, loomed, heat shrunk and now installed. I did forget one sleeve of heat shrink and ended up unwinding the main connectors to slide a piece on. After all this work, I wasn't going to have one joint with electrical tape....dammit.

Got the harness installed and terminated to the relay panel. Played around with routing to make sure I had slack and nothing touching where it would get hot. I had to drill and tap a couple spots to get clamps where I wanted them. I had to order more clamps to start going over the hoses.

The next steps are to start terminating accessories and the ECU power supply to the SwitchPro.

Other mentionables....Got the rear suspension powder coated, ordering GearOne super CVs and waiting to finish the engine setup before installing the rear suspension.
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this attention to detail is top notch! 🤩
 
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Mac said:
We have power!

Having a configuration issue. Everything works as advertised with the exception of ECU power. It comes on but when you try and turn it off through the SwitchPro, it cycles the fans and won't turn off. You have to kill the battery.
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I assume you have something back-feeding the ECU switched circuit. With the battery unplugged, use a DMM and probe for continuity from the ECU trigger coming out of the Switch Pro to the output side of the relays for the fans and other ECU-on circuits to see if you're looping power somewhere.

Clean ass yob though, and looks actually functional, not just pretty.
 
Mac said:
We have power!

Having a configuration issue. Everything works as advertised with the exception of ECU power. It comes on but when you try and turn it off through the SwitchPro, it cycles the fans and won't turn off. You have to kill the battery.
Click to expand...
Are your fan relays still grounded by the FT?
 
Rockwood said:
I assume you have something back-feeding the ECU switched circuit. With the battery unplugged, use a DMM and probe for continuity from the ECU trigger coming out of the Switch Pro to the output side of the relays for the fans and other ECU-on circuits to see if you're looping power somewhere.

Clean ass yob though, and looks actually functional, not just pretty.
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Not sure I'm following.

I have a power distribution that has a main battery disconnect. From there, the power distribution feeds the relay power through breakers and the Switchpro. From the Switchpro, I have a main power on/off (button 8) then an ECU button to turn the ECU on (button7).

Everything is working with the exception that the Switchpro is not turning off the ECU. Once the relay is latched, it's not unlatching. I read out the Switchpro distribution and it is controlling power but the ECU circuit is only dropping to 6 volts and staying latched. Still troubleshooting this. I've removed wires form the relay and trying different combinations to try and figure this out.
 
Mac said:
Not sure I'm following.

I have a power distribution that has a main battery disconnect. From there, the power distribution feeds the relay power through breakers and the Switchpro. From the Switchpro, I have a main power on/off (button 8) then an ECU button to turn the ECU on (button7).

Everything is working with the exception that the Switchpro is not turning off the ECU. Once the relay is latched, it's not unlatching. I read out the Switchpro distribution and it is controlling power but the ECU circuit is only dropping to 6 volts and staying latched. Still troubleshooting this. I've removed wires form the relay and trying different combinations to try and figure this out.
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There's probably one sad little strand of wire, or something stupid like an alternator light, somewhere making continuity back to the battery on the ECU's switched power wire (output of the Switch Pro). Either the ECU turns on relays (fuel pump, fans, ignition) that are then backfeeding the ECU switched power, or something else is hinky. Ruling out the switch pro would be just unplugging the output of it, or pulling the power terminal from it.

If that doesn't do it, the above procedure would be how you'd check for which circuit is back-feeding. Just set the DMM to Ohms with the sound chime:

1741290254153.png

Put one probe on the ECU's switched power wire, then the other on shit that turns on FROM the ECU (like fuel pump, fans, that kind of shit) and see if you hear the chime go off to narrow it down. Only other thing I can think of is some constant + source from the battery is bridged over VERY slightly. Not enough to fire the ECU and associated relays, but enough to keep it going once energized.
 
there are ground loops possible with some ecus. all powers must come from a "main relay" post ecu. so the switch pro should only power up the ecu input (nothing else) it would be common for folks to have this same wire power up the ecu also give power to the 86 coil side of the relays--you "cant do that" or anything like it. (with some ecus) to change that routing the ecu gets a dedicated input from switch pro, then the ecu grounds a realy that can then supply power to the 86 pin of all relays, etc

try pulling all your relays. power up ecu and then see if it turns off. if it does then you have a looping issue going on
 
03/07 UPDATE

Electrical all checks out.

The issue was one wire was connected on the wrong really pole and yes, causing a looping issue. (@John@Outfront , Thanks for the input). So a reposition of that wire and everything works as advertised. I was cringing at the idea that I might have something off in my harness after all the work I put into it.

So on to the next phase.

I need to go over the engine and trans, and check all the hoses, connections, bolts, etc. I need to clamp the hoses to prevent rubbing and secure in place. Then, install the rear suspension. I hope to have it back to a roller by next week. In the meantime, I need to start sanding and taking panels down to powder coating. I hope to order my new seats today or early next week.

Getting there!
 
Mac said:
03/07 UPDATE

Electrical all checks out.

The issue was one wire was connected on the wrong really pole and yes, causing a looping issue. (@John@Outfront , Thanks for the input). So a reposition of that wire and everything works as advertised. I was cringing at the idea that I might have something off in my harness after all the work I put into it.
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cool!
 
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