Race Neon info on stripping my wiring harness down

[dave.franchino@gmail.com]

Howdy,

We are building a neon for the 24 hours of lemons series. Using an R/T motor. We'd like to strip down the engine compartment as much as possible to eliminate possible failure points. We have no dashboard, no lights, no ABS, no power steering, etc. Everything is stripped out to save weight. All was want remaining is the bare minimum for making the engine run.

We went through the motor compartment wiring harness and engine wiring harness and made a list of what things we think we can eliminate. I also copied the relevant sections from the repair manual justifying why we think we can eliminate these sensors. Can anyone confirm we're not pulling out something that will make the motor run poorly (or leaving something in that can be pulled out?). Thanks!!

Keep:

Engine Coolant Temp Sensor
Engine Oil Pressure Switch
Camshaft Position Sensor
Crankshaft Position Sensor
Fuel Ejectors 1-4
Inlet Air Temperature Sensor
Knock Sensor
Manifold Absolute Pressure Sensor
Manifold Tuning Valve Solenoid (R/T)
Oxygen Sensor 1/1 Upstream
Throttle Position Sensor

Remove

Ambient Temperature Sensor
Battery Temperature Sensor
Evap / Purge Solenoid
Idle Air Control Motor
Input Speed Sensor (not sure we have these)
Output Speed Sensor (not sure we have these)
Oxygen Sensor 1/2 downstream
Radiator Fan Motor (Can we just hardwire this?)
Vehicle Speed sensor
A/C Compressor Clutch
A/C High Pressure Switch
A/C Low Pessure Switch
Backup Lamp
Brake Fluid Level Switch
Brake Lamp Switch
Controller Anti-lock brakes
Left Fog Lamp
Left Front Side Marker Lamp
Left Front Wheel Speed Sensor
Left Headlamp
Left Park/Turn Signal Lamp
Low Note Horn
Power Steering Pressure Switch
Right Fog Lamp
Right Front Side Marker Lamp
Right Front Wheel Speed Sensor
Right Front Wheel Speed Sensor
Right Headlamp
Right Park/Turn signal lamp
Speed Control Servo
Windshield Washer Pump

Found this in the manual. You’ve probably seen this.

Based on inputs it receives, the PCM adjusts fuel injector pulse width, idle speed, ignition spark advance, ignition coil dwell and EVAP canister purge operation. The PCM also determines the appropriate transmission shift schedule and shift points, depending on the present operating conditions and driver demand. The PCM regulates the cooling fan, air conditioning and speed control systems. The PCM changes generator charge rate by adjusting the generator field. The PCM also performs diagnostics.

The PCM adjusts injector pulse width (air-fuel ratio) based on the following inputs.
• Battery voltage
• Coolant temperature
• Exhaust gas content (oxygen sensor)
• Engine speed (crankshaft position sensor)
• Intake air temperature
• Manifold absolute pressure
• Throttle position

The PCM adjusts ignition timing based on the following inputs.
• Coolant temperature
• Engine speed (crankshaft position sensor)
• Knock sensor
• Manifold absolute pressure
• Throttle position
• Transmission gear selection (park/neutral switch)
• Intake air temperature

The PCM also adjusts engine idle speed through the idle air control motor based on the following inputs.
• Air conditioning sense
• Battery voltage
• Battery temperature
• Brake switch
• Coolant temperature
• Engine speed (crankshaft position sensor)
• Engine run time
• Manifold absolute pressure
• Power steering pressure switch
• Throttle position
• Transmission gear selection (park/neutral switch)
• Vehicle distance (speed)

The Auto Shutdown (ASD) and fuel pump relays are located in the Power Distribution Center (PDC). The camshaft position sensor and crankshaft position sensor signals are sent to the PCM. If the PCM does not receive the signal within approximately 1 second of engine cranking, it deactivates the ASD relay and fuel pump relay. When these relays are deactivated, power is shut off from the fuel injectors, ignition coils, oxygen sensor heating elements and fuel pump. The PCM contains a voltage converter that changes battery voltage to a regulated 5 volts direct current to power the camshaft position sensor, crankshaft position sensor, manifold absolute pressure sensor, throttle position sensor, A/C pressure switch, A/C pressure transducer, and vehicle speed sensor.

Questions:

• From this, do we need both O2 sensors?
• If we drop air conditioning sensor, power steering sensor and battery temp, will anything weird happen at idle. Do we care if idle is a bit wonky?
• The PCM controls the evap purge. Do we need an evap purge? Can we just drop this?

[neonrog]

I think you are on the right path, but my knowledge is based more with older pre-OBD Chrysler turbo cars. I believe you are going to want to keep the idle control motor, simply because, the car will be sitting idling in the pits, waiting for your turn on the track and so forth. Also, any of the solenoids you eliminate, consider a resistor. And I'm not sure what value resistor works best. The computer sends a signal for the solenoid to open or close. If it doesn't see continuity on that line, it might set a code and put the system into limp mode. Not optimal running for a race car.

I have done two pre-OBD harness', one for a drag car, the other in a dune buggy and over 12 years ago. I have a Ford Ranger powertrain that I want to stuff into something (four banger we took out for an Explorer V6...). I ALMOST had my hands on a 1963 International Scout 80, just the body and frame... But if I find something to toss that powertrain into, I'm going to have to whittle that harness down....

Ever since helping that buddy with the dunebuggy, I've wanted to do the same. I think now I'd use a 2000-2002 wiring harness and PCM to avoid the issues of the 2003 and up NGC computer... Good luck, let us know how it goes!

[ragek23]

Talk to kevin sykes on facebook he probably can get you a PCM reprogrammed to stop all these removed sensors from tossing the car in open loop.

[dave.franchino@gmail.com]

Rage,

There are a zillion Kevin Sykes on Facebook. Do you have any contact information for him?

Thanks!

Dave

[NickKo]

Rage,

There are a zillion Kevin Sykes on Facebook. Do you have any contact information for him?

Thanks!

Dave

This is his site:
http://www.sykedecutuning.com/

I understand that he is easiest to reach via Facebook.... You can try emailing him, but depending on how busy he is (he runs his own business), he may not get back to you very quickly.


- Nick