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Frequently Asked Questions

Find answers to the most frequently asked questions about Painless Performance Products by clicking on the links below.

If you have a question not answered on this page, go to the Contact Us section and submit your question to our Tech Support or simple give us a call 8-5 Monday-Friday at 800-423-9696.

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4.8L - 5.3L - 6.0L
60217 and 60218 truck harnesses fit these engines.

The Painless Performance 60217 and 60218 harnesses fit 1999-2005 non throttle by wire 4.8L, 5.3L and 6.0L engines and 4L60E/4L80E transmissions.
  
Note: throttle by wire engines can be retrofitted with a cable throttle body to be used with these harnesses.
Note: these harnesses do not include the flex fuel injector connectors.
 
Flex Fuel

General Motors manufactured full size trucks with two different types of flex fuel systems.
The early type used from 2002-2005 utilized a fuel composition sensor (FCS).  This sensor measured the ethanol content and temperature of the fuel and sent a pwm signal back to the ECM.  The ECM applied this signal to a look up table which gave different commanded air/fuel ratios according to different amounts of ethanol in the fuel.  Fuel injectors on these engines are larger than the non-flex fuel type and also use a different connector.  ECMs from these vehicles require the signal from a FCS in order to command the correct air/fuel ratio.  If no signal is present the ECM commands an air/fuel ratio that would allow the engine to operate regardless of ethanol content in the fuel.  This default afr is  rich for 100% gasoline and lean for 85% ethanol. 
 
Options to using a 2002-2005 flex fuel engine with a Painless fuel injection harness:
  1. Keep the flex fuel design when transplanting the engine which requires a FCS sensor along with the matching ECM.  Painless harness numbers 60221 & 60222 are designed to use the flex fuel calibrated ECM, injectors, FCS and factory throttle by wire system.  These harnesses are also designed to operate the 4L60E and 4L80E transmissions.
  2. Do away with the flex fuel design by changing out the fuel injectors and changing the VIN on the ECM to a non-flex fuel VIN.  Call the Painless tech line for more information on this.  Painless harness numbers 60221 & 60222 come with a pigtail that allows for connections to non flex fuel truck injectors.
In 2006 GM changed the way ethanol percentage of fuel was calculated by their trucks.  This new system was deemed Virtual Flex Fuel System.  Instead of using an additional sensor in order to measure ethanol content, the ECM had a software upgrade which allowed it to make this measurement by utilizing the fuel tank pressure sensor and level sensor signals.  At a key on event the ECM looks to see if the fuel tank level sensor signals atleast a 2 gallon change from the last key off.  If so, the ECM shuts the tank vent solenoid, monitors the fuel level and fuel tank pressure.  These readings are applied to a formula which gives an ethanol percentage.  The commanded air/fuel ratio is then changed according to ethanol percentage of the fuel.
 
In 2006 GM trucks used the same 160 pin ECM with blue and green terminal position assurances as did the 2002-2005 trucks.  Painless harness numbers 60221 & 60222 are designed for this ECM and use the factory accelerator pedal and TAC module from the transplant vehicle.
 
Vehicle Antitheft Systems

All trucks manufactured with Gen III & IV engines have a serial anti-theft system.  The ECM, BCM, IPC and steering column communicate whether the correct ignition key is inserted into the steering column.  If so, the engine starts and stays running.  If not, the injectors are shut off and the engine dies.  This serial anti-theft system is only defeatable through ECM reprogramming.  Please go to the ECM reflash page on this website for more information about having your ECM reflashed.

 
Throttle by Wire Gen 3 Fuel Injection Harnesses.

Yes, we offer fuel injection harnesses to cover most of GM's V8 throttle by wire lineup. 60219 & 60220 cover 2000-2002 Gen 3 truck engines with throttle by wire and either the 4L60E or 4L80E transmissions. 60221 & 60222 cover 2003-2006 Gen 3 truck engines with throttle by wire and either the 4L60E or 4L80E transmissions. The year break between 2002 and 2003 is because of a throttle body design change for the Gen 3 truck engines.  Engines built in 2002 or earlier came with a throttle body much like the LS1 in the Corvette.  These throttle bodies are easily identified by the black TAC motor on the passenger side of the throttle body and the TPS opposite to it.  2003 and later throttle bodies have the TAC motor and TPS both on the passenger side.
 
60219 & 60220 harnesses fit these engines.

2000-2002 throttle by wire 4.8/5.3/6.0L with 4L60E/4L80E transmissions.  Must use PCM with service #12200411.