SebMDtuning

Hi guys,

I am in the middle of creating my own engine harness and I wanted to clarify some ignition, power and ground questions before jumping into the production.

Car: Civic 97 Coupe si
Used for: Drag racing only
Base Engine: B18C
Panel switch: ARC8000
Computer: Hondata S300 v2
Other: 16V battery

Goal: get rid of my OEM wiring and fuse box and make my own harness!

1- IGNITION
----
I am sending the ignition signal (relay#2) directly to the IGP1 in my S300 basically replacing the OEM main relay.

I am also sending another ignition signal (relay#6) directly to my ignition coil to power up my distributor separately.

Should I send the ignition signal to something else?


2- 12v POWER
----

Based on the following diagram, IGP1 receives power from main relay and IGP2 sends 12v to INJECTORS and IAC. I am planing on using a deadend plug to distribute the power and run some extra wires just in case I need a 12v somewhere else.






Can I use that power output to power up my cluster harness as well?

3- Grounds
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In my plan, I send PG1/PG2 and LG1/LG2 from 4 different wires directly to the thermostat on the engine. The I use a deadend connector once again to distribute that ground to connectors that requires it

Is this a correct procedure? Am I on the right path with those information?

Finally since I will be removing all OEM wiring, I plan on using a switch to control the ground on the ARC8000 panel so that the panel wont stay ON all the time, even tho I have a kill switch ON my wiring panel and on the rear bumper. Let me know if that is a good idea!

Thanks guys!

Seb

Former User

What's wrong with the OEM wire harnesses?

TomCat39

I'm going to hazard a guess that since it's a drag car, the OEM harness is excessive for what is needed.

Already using a stand alone Engine Management System so all extra wiring and peripherals (like lights etc) are redundant and dead weight. For drag, less is more.

I do believe that is the purpose of the goal.

OP feel free to correct me if I'm wrong.

SebMDtuning

Yes, it's mostly about the weight and efficiancy. Everything on my car servs a purpose, if it's not needed, it's not present.

Also the idea is to remove all extra wiring for signal performance. There will be no soldering, only new terminals hooked with tefzel wire. I can also control what I want the way I want it.

I just need to be 100% regarding the questions above.

Thanks!

TomCat39

I'm going to move this thread to the drag racing section as the 92-00 civic section is more stock repairs type of orientation.

The drag guys will likely know a lot more and be able to provide you the details you need more so than the regular guys like myself over in the regular 92-00 tech forum.

SebMDtuning

Thanks, good idea. Just noticed that there was a Drag Section!

turbohatch96y7

iTrader: (15)

igp 1 and 2 are both 12v inputs to the ecu.


All other 12v accessories ( vss, iacv, injectors etc) need a 12v signal also


As for ground.


I redid my entire engine harness more than once and did not use the thermostat as a ground. The motor is grounded to the chassis and should have 0 resistance when checking with a multi meter. I have all my grounds for ecu, vss etc grounded by the ecu kick panel.


Its up to you if you want to play it safe and use the thermostat as a ground.

SebMDtuning

Thanks alot for this!

So the ECU doesn't send any 12v to the accessories?

I guess I simply need to use my ignition relay to distribute the 12v to the ECU and all accessories?

Thanks for the clean answers!

a1320addict

iTrader: (1)

You're wrong. What should happen and what does happen are two different things, and you'll find multiple ground planes will play a role. If the chassis has not been modified past 'stock', the fact that you may have continuity through the frame doesn't tell you much more than just that.


The ECU should be grounded to the cylinder block/head, which should have it's own ground to battery. I'm sure the OP will have pumps/fans/etc grounded to the chassis, which is fine. Electronic devices which offer their own ground references (sensor 0V/logic) should always be to cylinder block/head/battery negative. The thermostat housing is simply where people are under the impression the ground should go, but I prefer a larger diameter receiving thread for a ring terminal.


*Seb*


For S300:
-Switched 12V to A25, B1. You can also have your injectors and any other 12V solenoid/sensor like front speed or rear speed share this supply.
-Block/BAT Ground to A23, A24, A26, B2. Logic grounds can be used as splice points for digital sensors and shield drains with an OE ECU.
-Cabin mounted control switch for the ARC is a good idea, however not required. The panel's relays are not physically 'on' until the corresponding switch is pressed. From memory - the ground you are talking about on the panel is solely the relay 85/86 ground. Even with a switch here, the panel will still be receiving it's 12V supply from battery unless your main kill switch is off. The only draw you'll have is the dim 'off' lights on the panel.

SebMDtuning

Wow thanks for this clear and really helpful answer a1320addict! I will put this into work tonight!!

So I guess, my IGNITION Button from ARC panel will send 12v to ECU on both IGP1 and IGP2. Then I will run an extra wire from that same relay to a dead end plug and use this to bring 12v to my accessories. I guess that answers my question whether or not I can power up my cluster with that

Only thing left is to find a good place to receive my grounds and to send the Logic ones to the accessories who needs one!

Seb

turbohatch96y7

iTrader: (15)

My sensors all read correctly.