Engine No Start Need Help Please


New Member
Feb 15, 2016
Just recently bought 1999 Mustang GT 4.6L 5 speed from a private owner and had the car for several months now. Here is what we were told when it was purchased:
was told it was a 5.4 (but its actually 4.6)
cams have been changed to next step up from stock
Higher flo injectors
flowmasters with x pipe
aftermarket throttle body
Computer tuned for changes and car needs to be run on 93 octane

This vehicle had a red wire running across the firewall to the passenger side and down near the accumulator to who knows where (guy told us it was for radio memory) which didn't sound right.

Long story short, car has been running great for 2 months until that red wire came undone. The red wire was run to a switch under the dash which had key power from the fuse panel. Car will no longer run (have no injector pulse)
Tried having keys reprogrammed but locksmith says his reader states "fault" and can not read code for key. Ive also tried my snap on scanner and it will not communicate either.

Any ideas?? I have no clue where that red wire could have been tapped into, but im guessing it was powering the injectors. Any help is appreciated ive been working on this for 3 days with no luck!
  • Sponsors(?)


New Member
Feb 15, 2016
The red wire that became un attached was in the engine compartment (have no idea where) the switch was inside the car hidden under the dash. Im trying to reattach it but have no clue what it may have attached to


SN Certified Technician
Aug 14, 2009
Houston Texas
Just wondering. Have you checked ALL of the fuses in the engine bay and driver's kick panel? Seems likely to me that the red wire shorted out and blew a fuse. Depending upon which fuse blew may have affected other car systems.


Drone Driver
Mod Dude
Mar 2, 2003
Sea of Tranquility
I'm not an expert on car alarms but I don't think any alarm components are under the hood except for the siren or horn. If the wire is under the hood my guess it's for that...and it wouldn't cause a no start. Try what wmburns said above on fuses.


I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
Sounds like you've lost power to the computer....do you have a schematic to check power and ground at the computer harness. Do you have spark ? Is the fuel pump coming on ? With a key issue the computer should still communicate. Most alarms kill starter power from the ignition switch. Hope you get it figured out.