S197 Transformation of Sweet Lorraine Build Thread Profile - S197 Mustangs

[TMSBOSS]

I could have used your advise BEFORE I pushed the car on the trailer!

You did hook up the trailer first.....Right?

 

[TymeSlayer]

Lesson learned in some cowtown in Nebraska.

 

[302 Hi Pro]

Tyme:

Hope you had a safe trip, looking forward to updates & pics.

 

[302 Hi Pro]

Got her snug as a bug as I'll be heading out to drop her off at HPR this afternoon for two track days with NASA. It's seems like it's been too long since I've done it, I'm worried I've forgotten something!View attachment 17901

Tyme:

Thread bump!

Was thinking about you & your trip to High Plains for your 2 day event. Hope all went well & Sweet Loraine exceeded your expectations. Forgive me if I’ve missed your update(s) in other threads.

 

[TymeSlayer]

Dave,

High plains started out great but after two runs the gremlins came out again. Car ran great but in my third run, the dash lit up in a turn and I spun out the car. This has now happened at PPIR and Hastings last year and now at HPR. Third tyme in a row. Good thing I didn't stall her because back in the paddock, like all the other events, she was dead. Turn the key and nothing but the battery was fine. Once again I had to disconnect the battery and let it sit overnite and then she'd start right up. It also happened after that at small neighborhood car show. I got there fine but this tyme after the car sat in the heat for four hours, I got the same thing. I've checked the relays and all electrical connections and everything seems fine. I suspect it's a PCM issue but the dealer tells me the PCM seems fine. We are going to replace it soon and see if that works but if not, I'm not sure what I'll do. The one common thread so far is that it seems to happen when the temps are in the 90s.

 

[cholmes1]

Any luck in finding your gremlin in the past month?

 

[302 Hi Pro]

TS:

Sorry to learn of you electrical event.

Did you get a chance to check the engine ground wires? I remember when we were installing our headers I had to repair my engine ground located at or near the R/S engine mount. It was literally hanging on by 2 threads when I discovered it @ about 12k miles.

What ever you end up doing, start with eliminating the simple things first.

Good luck & please keep us posted.

 

[TymeSlayer]

The saga continues. Relays were all changed out and all the wiring looks good. Dealer threw up their hands and insist the PCM is fine. They suggest I take the car to a speed shop. I'm also looking at an automotive electrical expert. First I'm going to my dyno guy and have him look it over although he says unless I can duplicate the problem, he's not sure what he can do but run an overall health check. It's going to be 97 here today and I'll try to see if I can get her to duplicate the issue.

 

[302 Hi Pro]

Let’s hope she burps on the Dyno so you have a datalog of the failure event.

This has to be most frustrating.

Think back to when this event first happened and what was the last mod or 2 you performed just before it happened? Could that be related?

Good luck TS.

 

[Coz]

What if you got a couple of those flexible gel cold packs and pack them around the PCU while en route and while you're at a car show? If it prevents the problem then that's it.

 

[302BOB]

Problems kike this can drive some of us crazy...for some of us, it's a short drive....best of luck with the fix!!!!...electrical problems like this can be tough to solve..not like the old days...as if I would know.......

 

[TymeSlayer]

Today's trail...
Started car at 9AM (Air temp is 78 degrees)
Back the car out into the driveway and let idle for five minutes.
Restarted the car with no issues @ 11AM (Air temp 90 degrees)
Restated the car with no issues @ 12PM (Air temp 92 degrees)
The gremlin returns @ 2PM (Ait Temp 95 degrees)
I get nothing. All lights light up the dash. Run the code reader and it shows no codes whatsoever.
This tyme I'm going to leave the battery connected (not reset the PCM) and see if it'll start later when the air temps cool down. In the past I would reset the PCM and have to wait overnight and she would start without issue in the AM. My thought process here is to isolate the issue away from the PCM and see it it's strictly a heat issue. Though it has done this while tracking the car, the last two tymes the car was just sitting in the warm temps.

 

[TMSBOSS]

May be helpful. Disconnecting the battery may have dumped the codes you were looking for.

 

[12coBoss]

So I have had a few issues caused when tracking or by heat. Alternator go bad, just flashed the check charging system message, never died or left me stranded, replaced it all was good. Had wires melt out of the connectors on the cam sensors, spliced in new connectors and all was good. Intermittent start issues when engine was warm. It took me a bit to find this since it was intermittent, but found a solder on the solenoid on the starter. Upgraded to the race starter and no issues after that. I know probably nothing related but something to get the mind thinking.

 

[TymeSlayer]

Left the battery connected and waited until temps dropped below 90 degrees. At 9PM the temp hit 89 and the car started right up. I guess the dealer was right and it's not a PCM issue. The car just doesn't like it when it gets too hot. Could it be the starter/solenoid? All the cables to it look good but could it overheat and just stop working until it cools off?

 

[TMSBOSS]

Yes. This was a problem with BB Chevys for years. Heat soak the starter and she would not crank. Let her sit, cool and it would crank. The dash is still a mystery though.

 

[67GTA]

Left the battery connected and waited until temps dropped below 90 degrees. At 9PM the temp hit 89 and the car started right up. I guess the dealer was right and it's not a PCM issue. The car just doesn't like it when it gets too hot. Could it be the starter/solenoid? All the cables to it look good but could it overheat and just stop working until it cools off?

How old is the battery? I can’t recall from your earlier posts if you’ve ruled that out. The electronics in these cars are so sensitive to battery voltage, and its possible that it could be a heat related issue with the battery itself.

 

[TymeSlayer]

The battery was replaced in 2017 and is putting out 12.75 volts cold. Does anyone know if the starters on these '12 Bosses came with a heat shield?

 

[TMSBOSS]

67GTA has a good point. When chasing odd electrical gremlins, the battery and then ground issues are the "Most Fun" to find.

12.75 seems low. 13.1 or above sounds right. Someone help me with this.

 

[67GTA]

The battery was replaced in 2017 and is putting out 12.75 volts cold. Does anyone know if the starters on these '12 Bosses came with a heat shield?

Agree with @TMSBOSS, 12.75 is a bit low. What brand battery? At 3 years old, I would replace the battery before chasing anything else.

**edit, I think the 12.75 cold is OK, (should be above 12.6), but still think it could likely be an internal short when warm.