2000 GT PATS Issue - No Start

[SilverNewEdgeGT]

Hello everyone,

So I've been working on my 2000 GT for the past month and have been making some great progress. I decided to drive it to work, and it started up no problem.

After leaving it parked, I went to put the key in the ignition and once I started it I heard what sounded like the starter, and then nothing turned on.

I had a theft light flashing but it wasn't with any frequency. And when I would try to turn the car on again I wouldn't get any power to anything (no lights or anything)

I left it there and came back with my other car to try and start it with a boost (I wasn't sure what was going on at the time). The boost didn't work, so I tried the "twisting the steering wheel" method and then I tried using the spare non chip key to no avail.

Finally someone came along with a big booster pack and after an hour of trying, the car managed to start and I drove it home. I since replaced the battery since I was told the cluster sweeps when the battery is low. After replacing the battery, the cluster is still sweeping once the key is turned in the on position, yet I'm still having the same no start issue.
I'm not entirely sure where to begin. I've checked online but there isn't a set solution. Any advice would be helpful! Thanks in advance.

 

[wmburns]

Based upon your description I don't think you have a PATS problem. I think you have a POWER problem. Why? The cluster sweep is a dead give away that power was removed from the PCM or Cluster sometime between the last shutdown and this re-start.

The other give away is "then nothing turned on" which is clearly a power problem. Ford factory PATS does not remove power to anything. It works by with holding fuel injector pulse.

Want more "proof"? Use an ODB2 scanner and try and "talk" to the PCM while this problem is happening. If this is a power problem likely it won't talk.

Note, there are more than one possible cause here. This could be a ground "issue". It could be a loose cable or fuse.

Here's some more information that may help.

1996+ Crank with no start check list
http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

 

[SilverNewEdgeGT]

Based upon your description I don't think you have a PATS problem. I think you have a POWER problem. Why? The cluster sweep is a dead give away that power was removed from the PCM or Cluster sometime between the last shutdown and this re-start.

The other give away is "then nothing turned on" which is clearly a power problem. Ford factory PATS does not remove power to anything. It works by with holding fuel injector pulse.

Want more "proof"? Use an ODB2 scanner and try and "talk" to the PCM while this problem is happening. If this is a power problem likely it won't talk.

Note, there are more than one possible cause here. This could be a ground "issue". It could be a loose cable or fuse.

Here's some more information that may help.

1996+ Crank with no start check list
http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

Thank you so much for your detailed information. It ended up being the battery terminal. I changed it but I didn’t fully clamp down the leads to the negative cable. However it still does a cluster sweep when the key is in the on position. The battery is brand new. The car starts up no problem now however.

 

[wmburns]

Don't be surprise if your car never completes an ODB2 "drive cycle". This means that it won't pass an ODB2 inspection. In addition the idle quality may be poor because the PCM isn't able to "remember" new idle trim values.

What could cause this? There are a number of "always on" "keep alive" circuits to maintain the PCM memory. Not a bad idea to test all of the fuses. But start out by paying close attention to fuse F2.21.

1999-2004 MY fuse panel schedule:
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271

Just wondering. How did you find where the poor connection was? Did you find it by voltage drop testing or by closer visual inspection?