08 GT Ran for about an Hour and Died mid-drive

[NigerianS197]

Good Morning All,
(Sorry If this is too long, but I'd like to be as detailed as possible)
This last weekend, my friend and I Installed some LTH with an O/R H pipe on my 2008 Mustang GT. It's both of our first times doing any kind on header, so you can only Imagine how long it took, but on Sunday afternoon everything was nice and secure. Naturally, since the my car has a new exhaust system, I needed a tune to keep the car from running poorly. I found Eric Brooks' write up on how to tune an S197 GT, and followed that to a T since my mod setup is similar (minus the CMCV Deletes). The only thing I didn't mess with was the the Timing since I wanted to get a better understanding of what I'd be doing before I change it up on my car. So I load the Tune into the car, and she fires up immediately without an issue. Great! We saw no visible exhaust leaks at the time, so I let the car run for about 10 mins. I shut her off, and Turn her back on 10 mins later, still no startup issues. Great! She has a smooth Idle and nothing apparent is jumping out. So the car runs fine for 20 mins. I resume the turn off and then on sequence 20 mins later, and she still fires up with no issues, So I got out for a Drive. I'm not really getting on the car, but I am testing to see if there are any warnings signs. The Drive goes very well (the exhaust sound was amazing), so I turn to head back to the starting point, and the Car goes limp and dies completely (got to about 3000-3150 rpm). The Drive had only been for about 10-12 mins at that point in time, and I wasn't really on the throttle that hard at all (about like 45%). Two days later, the car still won't start at all. I've already ruled out the Battery/Alternator since they are both connected and passed a continuity test, I don't believe it's the starter since the engine does want to turn over, but just can't/won't but I could be wrong on that. I've changed the fuel filter to a new one, and I've pressed the EFI reset switch on the car as well. I don't think it's the fuel pump, since I do hear the priming noises, but I may be wrong. The only parts that I haven't checked are the fuel rails, spark plugs, plugs, and other similar things. The Intake does suck in air upon start up attempt so I don't think that's the issue. Any Ideas on what else I could do? Flash in the stock again and try that? New tune rewrite? Has my PCM bricked itself somehow? What else should I take a look at? Also as a side note, The car isn't throwing any codes. I find that strange since the only code I turned off was the P0605 code. I tried checking the DTCs with both HPTuners and a code reader and both gave me the same result. Thanks in advance.

[B E N]

Reinstall stock tune and see if it will fire. These cars will run on a stock tune with headers, it just won't be optimal. If it runs start building the tune from scratch, all you should really have to change is the o2 delay. If it still doesn't run you know its mechanical, go through every sensor you were near and make sure nothing got loose.

[NigerianS197]

That was on the agenda for today. Anything specific warning signs that I should look out for?

[blackbolt22]

Good Morning All,
(Sorry If this is too long, but I'd like to be as detailed as possible)
This last weekend, my friend and I Installed some LTH with an O/R H pipe on my 2008 Mustang GT. It's both of our first times doing any kind on header, so you can only Imagine how long it took, but on Sunday afternoon everything was nice and secure. Naturally, since the my car has a new exhaust system, I needed a tune to keep the car from running poorly. I found Eric Brooks' write up on how to tune an S197 GT, and followed that to a T since my mod setup is similar (minus the CMCV Deletes). The only thing I didn't mess with was the the Timing since I wanted to get a better understanding of what I'd be doing before I change it up on my car. So I load the Tune into the car, and she fires up immediately without an issue. Great! We saw no visible exhaust leaks at the time, so I let the car run for about 10 mins. I shut her off, and Turn her back on 10 mins later, still no startup issues. Great! She has a smooth Idle and nothing apparent is jumping out. So the car runs fine for 20 mins. I resume the turn off and then on sequence 20 mins later, and she still fires up with no issues, So I got out for a Drive. I'm not really getting on the car, but I am testing to see if there are any warnings signs. The Drive goes very well (the exhaust sound was amazing), so I turn to head back to the starting point, and the Car goes limp and dies completely (got to about 3000-3150 rpm). The Drive had only been for about 10-12 mins at that point in time, and I wasn't really on the throttle that hard at all (about like 45%). Two days later, the car still won't start at all. I've already ruled out the Battery/Alternator since they are both connected and passed a continuity test, I don't believe it's the starter since the engine does want to turn over, but just can't/won't but I could be wrong on that. I've changed the fuel filter to a new one, and I've pressed the EFI reset switch on the car as well. I don't think it's the fuel pump, since I do hear the priming noises, but I may be wrong. The only parts that I haven't checked are the fuel rails, spark plugs, plugs, and other similar things. The Intake does suck in air upon start up attempt so I don't think that's the issue. Any Ideas on what else I could do? Flash in the stock again and try that? New tune rewrite? Has my PCM bricked itself somehow? What else should I take a look at? Also as a side note, The car isn't throwing any codes. I find that strange since the only code I turned off was the P0605 code. I tried checking the DTCs with both HPTuners and a code reader and both gave me the same result. Thanks in advance.

Bro this is so hard to read. You need to use the enter key more often lol...

What do you mean the engine does want to turn over? Are you saying it isn't spinning or fire up? What about a physical inspection all around where you did the work. Perhaps a wire got melted onto the exhaust or something of that nature.

[NigerianS197]

Lol, my bad for that man. So the engine does turn over actually, but just won't fire off. As a little update, yesterday afternoon I went over every possible plug/connection that may have been or was touch by me and my friend. Nothing jumped out to me, and I did make sure everything was grounded and connected. I also seem to have developed a parasitic drain somewhere, since the battery seems to drain at a rapid rate despite the car not being used. I suppose that narrows the problem to electrical? I did retry the stock tune and got the same result so that is proof something relatively major is off.

[blackbolt22]

Lol, my bad for that man. So the engine does turn over actually, but just won't fire off. As a little update, yesterday afternoon I went over every possible plug/connection that may have been or was touch by me and my friend. Nothing jumped out to me, and I did make sure everything was grounded and connected. I also seem to have developed a parasitic drain somewhere, since the battery seems to drain at a rapid rate despite the car not being used. I suppose that narrows the problem to electrical? I did retry the stock tune and got the same result so that is proof something relatively major is off.

Well cranking and cranking a car that wont start is very 'parasitic' too. Hopefully youve been charging it!

You could measure amps and then start disconnecting fuses...

[NigerianS197]

I promise I haven't been over cranking her . So far when I go check on the car after work, I have been charging the battery in the off chance it'll fire up. Today I was planning on checking each and every fuse, as well as the coils/spark plugs. Any thing else I should look out for?

[B E N]

If I leave the HPT module plugged in it will drain the battery, pull it if the car is going to sit.

[NigerianS197]

I've only had it plugged in like twice since the incident. I've already read that leaving a tuner plugged in is not good, so I've always taken the tuner with me

[decipha]

uhh did you put gasoline in the car?

[NigerianS197]

Lol I knew this question would come up. She had over half a tank, but I understand where the question is coming from. Usually I don?t go below a quarter tank before a fill up

[blackbolt22]

Lol I knew this question would come up. She had over half a tank, but I understand where the question is coming from. Usually I don?t go below a quarter tank before a fill up

What about fuel related failures, pump/filter or even bad fuel?

[NigerianS197]

What about fuel related failures, pump/filter or even bad fuel?

Replaced the fuel filter, and I do hear the fuel pump priming when the key is turned. I'm not ruling out fuel related issues though. Something up with the electrics since the car has been getting progressively weaker and weaker everyday. Something is on that isn't supposed to be on with the engine off, which may be the culprit. Maybe something in the cars ECU/ECM is saying it's already on, and that's what keeping the car from starting? Possible cause of the parasitic drain? I;m not really ruling anything out at this point.

[B E N]

You can log fuel pressure with VCM scanner, see where it is at and that will help verify your fuel system is good.

[NigerianS197]

Forgot to give an Update. I was able to figure out the issue. A Harness connection had come loose while I was driving, grounded out and fried both the Fuse and the Capacitor connected to it. Took a fair bit of time just to figure out where the issue was, but now I been driving again for a week with no issues. Car sounds fantastic and I'm a happy man again. I guess this was just one of those things where I could've happened happened regardless of what I had done or not