I have a 2005 Pontiac GTO. The original battery just died, so I replaced it. Now it will not start. It turns over, runs about five seconds, then shuts down. When I try to restart it, it will not even turn over. The battery I put in it is new and fully charged. Any Ideas? Thank you, Dave.

SOURCE: 2005 PONTIAC GTO gas pedal electrical plug

Connector Part Information
• 7223-9730-30 • 10-Way F (GY) Pin
Wire Color
Circuit No.
Function
1
BN
1271
Reference Low Signal
2
WH/BK
1164
5-Volt Reference Signal
3
L-BU
1162
Throttle Pedal Position Signal
4
--
--
Not Used
5
BU
1161
Throttle Pedal Position Signal
6
TN
1274
5-Volt Reference Signal
7
PU
1272
Reference Low Signal
8-10
--
--
Not Used


Hope that helps, Good Luck

SOURCE: Problem starting 2004 Pontiac GTO

have you had the starter checked

Marvin

• 85242 Answers
• Posted on Mar 30, 2009

SOURCE: car starts run's 3 seconds shuts down

Your car is equipped with a system called PASSKEY standard on all GM cars and light trucks, try the following procedure to reset the system, the battery being dead will trigger the system.

PASSKEY LOCKOUT RESET GM CARS 1999 UP
1) Put the key in the ignition and turn to the "ON" position. Leave it that way for 10 minutes. After 10 minutes turn the key and take it out. Repeat this process (2) more times (3 times, 30 minutes total) This should reset the passlock system to recognize your key.

SOURCE: just changed original cats with direct fit magnaflow

Some systems actually depend upon a certain amount of restriction in order to work properly. The additional flow in the new system will mess with factory set flow expectations. If one of the O2 sensor wires have not been moved and have burned onto an exhaust pipe, You can either ignore the light if it's running well, or take the next (expensive) step and install a programmable engine control unit. However, in many states the light being on will cause you to fail inspection.
If you want to retain the exhaust system, you also could put a reducer in the pipe behind the cat to slow down the exhaust flow. It would not give you the added mpg that an open system will, but may restore the O2 sensor operation and likely you will still have the same sound effect that the system produces. Have a fault scan done...if it shows O2 sensor failure, that's where to go.

SOURCE: starts and runs 3-5 seconds and shuts down

Sounds like your security system is shutting the car down. You should be able to leave the key on for 15 minutes and it will reset itself. Make sure you are using factory keys, and they are in good condition.