Electrical Stock 03' Starting Issue After Alternator Replacement

[Jordan_FL]

basic rundown:
2003 mustang GT convertible
automatic trans
128k miles
K&N intake (only mod)

CEL codes P0340 P1233 P1237

so a few weeks ago i noticed that every once in a while the car would have the slightest issue starting, id get in for a cold start, turn the key, the car would fire up then die straight away. after a few times of this happening i got a cel code P0340, read up and saw this was usually the alternator. went and got it tested and confirmed excessive ripple. no other codes were stored at this time.

i bought a factory replacement unit and installed it myself, did all the usual precautions, disconnected battery etc. after the install i started the car up and everything checked out perfectly, no CEL, no sputtering and anything of that sort. after a 10 minute test drive i was satisfied that i was good to go and parked the car.

after about 4 hours i went back outside to meet up with my GF, as soon as i started the car up it began idling very rough and at a minimal rpm, i figured the car was just relearning its fuel map and whatnot so i decided to give it a minute to work it out, nothing changed, crappy idle. upon putting the car into gear the car died and would not start back up.

i switched the new alt out with the old once and it made no change.

the car threw 2 more codes p1233 and p1237

every once in a while you can get the car to start and idle very weakly for a couple of minutes but thats it.

id really be surprised is the fuel pump failed, just because it would be incredible coincidental for the alt and fuel bump to fail at the same time. but then again who knows.

 

[wmburns]

The P1233 DTC basically means that the fuel pump isn't running. This could be because it has failed. Or isn't getting power. At the risk of stating the obvious have you checked all of the fuses? Have you check the IFS shutoff switch in the trunk?

My vote is that you have accidentally disconnected something during the recent work. There's a larger black wire with a white stripe that runs around the battery. It usually connects to a larger single pin round connector.

Turn the key on but do NOT crank. Do you hear the fuel pump run for a few seconds at initial key on? If not STOP and find out why. The car will never run correctly until the FP runs during initial key on.

>>
P0340 - Camshaft Position (CMP) Sensor Circuit Malfunction

• CMP circuit open
• CMP circuit short to GND
• CMP circuit short to PWR
• SIG RTN open (VR sensor)
• CMP GND open (Hall effect sensor)
• CMP misinstalled (Hall effect sensor)
• Damaged CMP sensor shielding
• Damaged CMP sensor
• Damaged PCM

P1233 - Fuel System Disabled or Offline

P1237 - Fuel Pump Secondary Circuit Malfunction