Power wire upgrade and ground wire upgrade

scojack_2001

Livin' Like A Refugee
Anybody have any ideas on what kind of wire to use? And what gauge? Been fighting a high IDC condition and low voltage on my SM. Even the injector hotwire didn't seem to help. Car is getting 13.5V at the pump (has new Racetronix hotwire kit) and fuel pressure is 74psi at 27psi of boost. Running a single XP+ pump. Figured I'll start with the power wire and the grounds as well and see what that does.

I know nothing about electronics and wiring. So take me to school here and tell me what the best, most reliable way to do this is. How would I tie in the ECM power wire? Running a standard 75 series side post battery.
 

Boost231

What's An Intercooler
Staff member
What voltage is the scanmaster Reading? You sure you have a voltage problem or are you out of pump? You monitoring fuel pressure?
 

scojack_2001

Livin' Like A Refugee
What voltage is the scanmaster Reading? You sure you have a voltage problem or are you out of pump? You monitoring fuel pressure?

ScanMaster reads reads ~12.7 or so at WOT. Idle is higher, around 13.5V or so. Not sure on anything this car does any more... Pump seems to be fine. Getting 74psi of fuel pressure at 27psi of boost, at a 43psi base. Logging FP through the PL.

Gonna check and recheck all my voltages tomorrow if I can get time.
 

Nick Micale

Tech Advisor
Staff member
The most common electrical issues on our cars are due to improper grounds.

Direct current requires that the ground MUST return to the battery with the same conditions as the power side.

If you have 13.5 volts supply at an electrical component, the circuit must have the same "path" as for the return or ground side which means at least the same gauge wire.

A hot wire kit is only one leg for a proper circuit especially for an item that is critical for high performance when most all in-tank fuel pump output is measured at 13.5 volts or more

One illustration of this is a Scanmaster reading a volt or 2 less than the alt output because the SM is grounded to the body which is NOT a good path to the battery.

If you ground your fuel pump to the frame for example, that is a terrible spot for the electrical path to the battery as that is one of the worst electrical conductors to use?

A stranded copper wire vs. a 30 year old frame made up of several pieces of rusted, corroded low grade steel is no contest on which is better. :)

Where does Racetronix have you ground their hot wire kit?
 

scojack_2001

Livin' Like A Refugee
The most common electrical issues on our cars are due to improper grounds.

Direct current requires that the ground MUST return to the battery with the same conditions as the power side.

If you have 13.5 volts supply at an electrical component, the circuit must have the same "path" as for the return or ground side which means at least the same gauge wire.

A hot wire kit is only one leg for a proper circuit especially for an item that is critical for high performance when most all in-tank fuel pump output is measured at 13.5 volts or more

One illustration of this is a Scanmaster reading a volt or 2 less than the alt output because the SM is grounded to the body which is NOT a good path to the battery.

If you ground your fuel pump to the frame for example, that is a terrible spot for the electrical path to the battery as that is one of the worst electrical conductors to use?

A stranded copper wire vs. a 30 year old frame made up of several pieces of rusted, corroded low grade steel is no contest on which is better. :)

Where does Racetronix have you ground their hot wire kit?

Nick, I havent been under the back of the car in a while: but I believe its in the back on one of the bumper shock bolts.

As for the electrical issues, I'm going to start with a second new 8 gauge power wire from the alternator to the battery and ground the alternator case to the body and the battery. This may not help me any, but I feel it can't hurt.

Can i move the grounds for the FP hotwire and the SM to the negative battery post?

Also going to put my new billet tensioner on the car and a proper sized 5060635 belt. I'm running a 4060635 belt now.

As for the car itself, I have no intentions of racing the car until the fall. It's time to replace some worn out parts.
 
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