Scotty, got a big one messing with my mind. 2007 Ford Crown Vic Police Interceptor, 4.6L 2 valve, 228,000 miles.
My engine has what seems like 3 cylinders down at idle, and maybe 2 cylinders firing under load. I've been leaning towards coils and plugs, but have also been thinking it might be fuel starvation from a weak pump. Now for what holds everything up, my OBD port has no power, and scan tools aren't picking up that they are hooked to anything. I'm thinking that I have a bad fuse to the port, but hoping it's not a dying ECM. Plz help
If you aren't able to connect to the OBD port, you have a bad ECM. Not what you want to hear I know but that's a surefire sign the ECM is not communicating as intended.
So, that went from an $800 driveway repair, to a full shop visit
You're right to suspect it could be just a fuse.
In your case it would be fuse #16 in the passenger compartment.
| Fuse 16 | 20Amp | 2007-2008: Cigar lighter, OBD II |
If that fuse is OK you may want to determine if your data port has power and grounds to operate and communicate with a scanner.
Grab a multimeter and check Data Port Pin 16 for battery voltage (12 volts+) and both pins 4 and 5 for ground.
So switch the multimeter to 200K on the OHM scale.
Connect the black lead of the multimeter to a good ground and probe both Data Port pins 4 and 5 with the red lead.
You should be reading 0 on both pins
Now switch your multimeter to Volts DC and set it to the 20 volts scale.
Again, connect the black lead of the multimeter to a good ground and probe Data Port pin 16.
It should read battery voltage. Around 12 volts.
All Data Link connectors are the same for these 3 pins but be careful. Sometimes they're installed with the wide side on bottom. So in that case Pin 16 would be on the upper left instead of the bottom right.
Don't go poking around the other pins, just check these 3.
Thanks Jack62, yeah, got the fuse swapped, and pulled up a few codes, only 2 though, multiple misfires, and cylinder 7 misfire, problem is, the engine has at least 4 to 6 misfires under load, and the OBD only shows the 2 codes, but I have yet to get a good scan tool on it to pull saved codes
Thank you to both of you, I gotta get this worked out, and ya'll have helped
If you suspect 4 misfires under load check the freeze frame data from when it's throwing the codes. If it's a fuel starvation issue the pcm will be trying to adjust that lean condition by adding fuel.
See if the fuel trims are high positive on both cylinder banks or just that bank #2 cylinder bank
The obd port should be the same fuse as the cigarette lighter from my experience
