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5.0L (1979-1995) MustangTechnical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.
The following link has specific tests for code 87.When VPWR is mentioned,its referring to the Red wire.This wire goes hot when the ignition key is turned to the On or Start position. Its the switched 12volt wire in the ecm circuit and the wire is shared by alot of components. The eec relay,fuel pump relay and the injectors are just a few of the components powered by this wire.The wire begins at pin 37 & 57.
It's got a dummy switch in place and until recently it's never had any issues.
Dummy Switch??
Are you referring to the egr eliminator plug,when using the words dummy switch?? If yes,an issue with it wouldn't cause your problems.It just prevents the cel from coming on,if the egr valve has been deleted. If youre referring to mil eliminaters instead,to keep the cel off because of the missing o2 sensors,they wont work.
(Source: Joel 5.0 @ SBFTECH)
**** MIL eliminators are only used for the downstream or post-cat O2 sensors (not used for fuel trimming) in OBD-II setups.... not present in OBD-I EEC's. If you install MIL eliminators to replace the upstream O2's, you will cause false info on which the EEC will calculate incorrect fuel trims. ****
If you delete the o2 sensors on a 86-93 Mustang,you will limit the EEC to use the base tables programmed in the system and no "learning" (adaptive strategy) regarding fuel trim corrections will happen.The system will operate in a permanent open loop mode,
which will disable the adaptive learning feature of the EFI system.
Last edited by wbrockstar; 03-21-2018 at 09:06 PM.
Im not sure what you mean by a dummy switch for the 02 sensors, unless it has an 02 simulator attached, the dummy plugs are not going to show the rapid on/off wave form the computer uses to trim fuel and timing.
Ping or detonation as it is other wise known is caused when the fuel ignites to far before top dead center. That can be caused by a fuel mixture that is too lean, over advanced timing, or a hot spot on the valves, piston , or cylinder walls from a collection of carbon. If the computer has not been able to trim the fuel mixture it defaults to an over rich condition. While it may seem as if the car is running ok, it really is not. If left to run in this condition it will cause a build up of carbon on the valves, piston and walls. Eventually this carbon build up can start to glow red causing the fuel mixture to ignite as it enters the cylinder.
03-21-2018, 09:27 AM
