ctuttle

So I have a 2009 GT and I have modified it up a good bit, Long tube headers (no cats), FRP exhaust, JLT II CAI (93 octane Doug Studdard race tune), Granatelli Super coils, Deleted CMC valves, Steeda UDP. Now up until last Monday she was running like a champ and then all of a sudden it cut out while driving it and read "Check Charging System" on the dash. It picked right back up and ran fine all the way to work (7:30 AM about 70 degrees outside clear day). This happened again twice that day on the way home still clear but about 95 degrees outside and both times it happened when I accelerated the second time was on the interstate on ramp and I was getting on it but not real hard. So then later that night after driving it to dinner it would not crank at all, when you turn the key to the start position it does nothing lights all still work fine and the mileage and trip readout changes to ----Trip ----Miles when you turn it to start. it will flash through on the display and change from Check Charging System to Check Fuel Cap to Fuel Level Low and maybe a few others I can not remember exactly at this point. I had for roadside assistance tow it to a local dealer where of course when they went out to check it it fired right up like normal, They had it a week and never fixed it or for that matter made any real attempts to diagnose it. So I picked it up and brought it back home, it ran fine all the way home and in fact I really got on it and even got a little sideways in 2nd gear, she was running great. Died on me later while backing it out of the driveway so it clearly a reoccurring problem

What I have tried (Current mileage 36,330):

1st I re-tuned it using the SCT2 tuner that I have and reloaded the 93 octane race tune that was in it before, no change ran great when it would start but still died from time to time and would not restart right away.

2nd disconnected the battery for 30 - 45 minutes and reconnected and re-tuned same results as the previous step.

Nuke

Intermittent issues are always a PITA to diagnose and resolve. It certainly sounds like a loss of battery/alternator power so I suppose I'd start by looking at the obvious wiring at the battery and the alternator. Use the wiring diagrams (http://iihs.net/fsm/?dir=1) to help you troubleshoot. Good luck.

ctuttle

Thanks Nuke I will check that out and I guess if I can get it to the auto parts store they could check the alternator without me having to disassemble the engine to pull it out as well as load test the battery. I would love it if it was just an alternator or bad battery, I am hoping it is not a bad ECU or it is trade in time, while it is running of course.

gt500kr

Hi there,

I have a gt500 kr and am experiencing the exact same problem.. I would love to know what your fix was....! Am getting fault codes for PATS System and open circuit PCM.... NEED HELP!
my car stopped at 100kph with same dash readings check charging System, check fuel cap now it wont turn over!

hammeron

i think it's gonna be one or the other

Nuke

The hackles on the back of my neck went up when I read the aftermarket COPs. I'm not sure if they'd cause the read-out that he's getting but when someone with aftermarket COPs has drivability issues, I usually suggest you rule them out first. They've been know to cause issues.

gt500kr

i forgot its just been converted from left to right hand drive... only been on the road for a week... checked every connection tested every relay.. still have trouble codes.. forgot to mention i was getting failsafe msg before all this occured and it wasnt hot or overheating...
nuke ill check for aftermaket COPS today... interesting...

ctuttle

Ok guys so here is what I have learned through an exhaustive search, many hours trouble shooting and several ford technicians. With a special thanks to Satcher Ford in Aiken, SC and Steve their Shelby tech, he is amazingly intelligent and helpful.

So 1st lets take a look at the “Possible” root causes there are two right off the bat that can be checked and after a good deal of research about 75% of the issues are corrected with one of these two steps.
A. Check the fuse box under the hood and check the relay in space #53. It looks just like a fuse with the exception of it being black and has a triangle on the top and a line through it denoting it is a diode. Now you may or may not have a multimeter that will check diodes if you do test it to be certain it is working and you should get a reading one way and nothing the other. A diode simply allows voltage to flow only one direction and not the other. This diode has long history related to the AC system on cars and has been a source of a lot off dead batteries and charging system gremlins
B. In the smart junction box (SJB) located in the passenger side floor kick panel remove the cover and search for fuse #19. Now while I am not sure what exactly this fuse goes to it has something to do with one of the several computers onboard in the 2005 – 1020 mustang models.

Ok so let’s assume all of this has been checked and still “No Joy”, well on to the next step checking the network to ensure it is all on its toes and ready to go. According to Steve at Satcher, you have three computers on the network in your pony. Now when all three of these computers are online you should get e resistance reading of 120 Ohms when you measure it from the OBDC connector under the dash. So let’s check and see if we have all of our computer’s shall we:
a. Looking at the OBDC port there are several pins that are gold in color and some that are blank. So If laying on your back in the floor board counting from your right to left pin one has no mate then there are 2 & 3 and 4 & 5. You want the pair 4 and 5 and test across these pins for continuity and ensure you have 120 Ohms. If you don’t you have lost one of the commuter’s on the network and the search has narrowed.
b. Now systematically disconnect each computer form the network and check after disconnecting each one to see if you reading “DOES NOT DROP” further and that is your culprit.
Ok so lets say you have read all of my ranting’s here and tested everything and still “No Joy” you may have a more sinister problem such as I did, oh and by the way mine was self-inflicted as so many of these problems are. My problem boiled down to a hood pin that I put in and the pigtail on the pin. I needed someplace to put the pigtail and attach it under the hood that looked, you know….nice. So with no regard for posterity of my pony or and blatant disregard for mechanical soundness I loosened a bolt just over the passenger’s side headlight that already had a wire attached to it and placed my pigtail (shielded cable mind you) underneath this bolt. That’s right between the ground wire and the body of the car, so all it had to connect itself to the car via was the bolt itself. Now this work for many months nearly a year to be more precise, but then it became loose and intermittently cause the computer on that side of the car to drop down to 6 volts vs. the 12 it should have been. So at the hands of my mechanic he found the voltage drop at the computer and saw it was only getting 6 volts vs. the 12 it needed to operate properly and after replacing the ground wire the beast cranked right up and away we went down the road never to be revisited by the electrical gremlins ever again.

Now your problem GT500KR I am assuming is the same problem since you just had a good bit of your computers disconnected to convert to right hand drive so I would certainly check there first and disregard all of the early diagnostic mouse chasing I described.

I certainly hope that this will help someone else in the future as my pony was down sick for many months before I was able to get he back on her wheels and revved up and racing again.

regarRs,

Clade

gt500kr

Ok so here is the update..

ctuttle, thankyou very much for your post, it gave me some fresh ideas which in the end wasnt the exact problem but lead me close... All this breaking down and intermittent DTC codes was giving me the s**ts!!! so im on the side of the road broken down with "failsafe mode"...with the key in the "ON" position i started looking at the fuse box.... Whenever i touched or tapped with my finger on relay 22 (PCM relay) the car would "reset" fuel would re-prime as if i had just turned the key on. So to get the car home was as simple as tapping this relay, start the car and off i go... Since working on this particular problem i have learnt that the gt500 fuse box has its own built in distribution network beneath the relays and fuses which is not visible to the eye, nor can you split the box to check for damage. So long story short, the company that did the conversion stepped in and replaced the entire fuse box this morning and the car seems to be "good as gold".... I drove the car for 20min this afternoon and didnt miss a beat, although when i got home i popped the fuse box and found many of the relays too hot to touch, while working in the electrical industry i know this is quite normal in some circumstances, but cant help wonder if excessive heat had damaged the first fuse box and if excessive amperage running through the relays is the cause, which could revert back to a wiring issue within the car.. There are no present polarity issues within PCM or fuse box circuits.. so my question is DOES ANYONES RELAYS GET HOT TO TOUCH UNDER HOOD???

StankinStang85

Had this same issue and turned out to be that #53 diode you explained.....