General Installation Troubleshooting

WHERE

DOES THE SINGLE RED WIRE COMING FROM RELAY BLOCK GO?

•  

 The red wire provides switched power signal for the PCM.

Connect to a 12 volt source that has power with the key ‘ON’ AND WHEN

‘CRANKING. Note that in older GM Vehicles, the ignition wire in the

engine compartment (White cloth covered) is not a 12-volt source. The

most common spot to find this type of power is in the factory chassis

fuse box. It is typically marked as ‘IGN’ power NOT ‘ACC’ power.

 

WHERE

DO THE TWO RING TERMINALS AT THE STARTER GET CONNECTED TO?

•  

 The 2 black wires with the large ring terminals provide all

the power to the harness. They get connected to the large stud on the

starter, which should have battery power.

WHY

DON’T MY OXYGEN SENSORS PLUG IN?

•  

 PSI harnesses are designed to use the most popular Oxygen

sensor applications. For peak engine performance, PSI recommends the

oxygen sensors be replaced, especially if vehicle/engine history is

unknown.  New Delphi Oxygen sensors can be purchased from PSI,

or Table 2 of your harness instructions will provide GM part numbers

for the correct sensor.

WHERE

SHOULD I INSTALL MY OXYGEN SENSORS IF I HAVE LONG TUBE HEADERS?

•  

 O2 sensors should always be installed as close to the engine

as possible in order to allow for proper sensor heating and function.

The further from the engine the sensors are installed the more time the

sensors will take to heat up and put the engine in closed loop.

HOW

DO I HOOK UP MY AC REQUEST WIRE?

•  

 The AC Request Wire must be hooked up to a 12-volt source

when the ac compressor clutch is engaged.

WHERE

DO I PLUG IN THE PURPLE AND YELLOW WIRES.

•  

 This varies depending on your specific Harness.

 Please check your wiring harness instruction manual - Instructions

WHAT

DO I DO WITH ORANGE WIRE?

•  

 Run to ground (IN PARK AND NEUTRAL). It is not a neutral

safety wire and will not prevent the engine from starting. Hooking this

wire up is ‘Optional’.

DO

I NEED TO HOOK UP MY OIL PRESSURE CONNECTOR?

•  

 Oil pressure wiring only needs to be hooked up if you are

using Variable Valve

Timing (VVT). This function is only present on Gen IV (58X) engine

applications. For all other applications the engine oil pressure wiring

is not required to make the engine function properly. When using an

aftermarket oil pressure gage, you must use the sender that came with

the gage and wire it directly.

WHERE

CAN I INSTALL MY COOLANT TEMPERATURE GAUGE SENDER?

•  

 When using an aftermarket water temperature gage, the sender

that came with the gage must be used and wired directly to the gauge.

Most aftermarket gauges use senders with standard US threads. However,

LS engines have metric threads, therefore a fitting must be used to

adapt the threads. The port on the rear of the passenger cylinder head

is most commonly used for this function. These adapters are available

through PSI.

HOW

DO I WIRE UP MY FUEL PUMP?

•  

 Using Figure 2 and specific connections indicated in Table 4,

connect the wiring as directed. All connections in table 4 are required

unless otherwise noted.

HOW

DO I WIRE UP MY SPEEDOMETER?

•  

 Connect our black "under dash" wire to speedometer. NOTE: Do

not tap into VSS wiring in the harness as this can result in the

transmission NOT shifting due to a split VSS signal. Following

installation, ensure proper calibration of the speedometer per the

manufacturer’s instructions.

HOW

DO I GET MY AUTO-METER TACHOMETER TO WORK?

•  

 Connect our white “under dash” wire to their green wire of

your tachometer. Note that most aftermarket tachometers work with a

12-volt signal. However, LS controllers use a 5-volt signal which is

not directly compatible with most aftermarket tachometers. In these

cases a resistor must be wired into the tachometer signal wire. This

wiring diagram is located in the PSI instructions which came with your

harness.  

NO

SIGNAL TO THE TACH AND SPEEDO GAUGE(S)?

•  

 Most aftermarket tachometers work with a 12-volt signal.

However, LS controllers use a 5-volt signal which is not directly

compatible with most aftermarket tachometers. In these cases a resistor

must be wired into the tachometer signal wire. This wiring diagram is

located in the PSI instructions which came with your harness.

VEHICLE

RUNS PERFECT BUT NO 5V SIGNAL AT TACH WIRE (GAUGES)?

•  

 Check that gauge is installed correctly.

•  

 Contact PSI Tech Support to determing if PCM 'Tach

Resolution' is set correctly.

I

HAVE A TH350/MANUAL TRANS. DO I NEED TO PLUG IN THE VSS?

•  

 The VSS is not required, however, it is recommended. In some

instances, if the VSS is not hooked up, the PCM will not know how fast

the vehicle is going and therefore under hard stopping conditions could

abruptly hunt for idle or stall. This condition can be alleviated by

installing a VSS or through a local tuner once the swap is completed.

CAN

I EXTEND MY MAF CONNECTOR WIRING?

•  

 Yes you can extend the MAF connector using a properly made

extension harness. These are available through PSI in varying lengths

to fit many different configurations.

CAN

I EXTEND MY OXYGEN SENSOR WIRING?

•  

 Yes you can extend the oxygen sensor connector using a

properly made extension harness. These are available through PSI in

varying lengths to fit many different configurations.

CAN

I TAP INTO THE VEHICLE SPEED SENSOR (VSS) WIRING PROVIDED WITH MY

HARNESS SO MY SPEEDOMETER WILL WORK?

•  

 No, at no time should you tap into any of the engine sensor

wiring supplied with your PSI harness. You speedometer should be wired

per the manufacturer’s instructions. This typically requires that you

connect the speedometer to the output wire supplied with the PSI wiring

harness ‘under dash wiring’ section.  

CAN

I TAP INTO THE COOLANT TEMPERATURE SENSOR WIRING PROVIDED WITH MY

HARNESS SO MY COOLANT TEMPERATURE GAUGE WILL WORK?

•  

 No, at no time should you tap into any of the engine sensor

wiring supplied with your PSI harness. You temperature gauge should be

wired per the manufacturer’s instructions. This typically requires the

sender that came with the gauge to be used.

HOW

DO I ENSURE THAT MY COIL SUB-ASSEMBLY WIRING HARNESS IS ON THE CORRECT

SIDE?

•  

 When using PSI coil sub-harnesses it is critical that they

are oriented correctly. An easy way to check orientation is to confirm

the wire color in position 'C' of each coil connector. The colors and

corresponding cylinders are as follows:

HOW

DO I MOUNT MY EXTERNAL FUEL PUMP TO MY VEHICLE?

•  

 The external fuel pumps require insolated mounting brackets

to ensure proper, long lasting performance. Most customers will

fabricate mounts based on their application or use rubber insulated

clamps

to secure the pump.

•  

 If using a Walbro external fuel pump, a mounting kit is

available through PSI.