Car just die at idle

[302 Hi Pro]

Did you check fuel pump voltage when it died? It would be good to know if the fuel pump had power and was operational during the 10-15 minute period of the no start condition. Then you can check fuel pump pressure at the left side fuel rail to ensure you have fuel supply.

It would be a start in ruling out possible causes. Next I would be looking at the ignition system, to see if a No Spark condition exist. Again, this testing has to take place during the 10 - 15 minute period of the No Start condition.

You have to start somewhere, right?

Please keep us posted with your progress.
Thanks SB,
2HP

 

[Swiss Boss]

I can check fuel pump voltage next time.

As far as pressure there is no easy way to check it. The stock fuel rail doesn't have a port for a gauge.

 

[Swiss Boss]

I did more test.

Car is still stalling and won't start until I wait 10min. I do have fuel pressure.

Could a bad coil/spark plug has this kind of symptom? I'm going to check them tomorrow.

 

[BigTaco]

I've been following this thread and have some thoughts. I would not chase down vapor lock but, I think that you should focus on what the engine strategy is and what changes going from cold and into warm up. It's not a tuning issue either based on what you have shared. I'm wondering what changes when a coyote engine is cold vs. when it's hot? The computer is telling the throttle body to change its angle but I'm sure there is more to it than that; or maybe it's that simple. The throttle body either can't stay open when it's warmed up because it's malfunctioning and it needs to replaced or perhaps there is a fault in the drive by wire components. Sorry if I'm rambling, just trying to help...

 

[k98dave]

+1 on Throttle Body&/or Electronics being a problem. I gather that if you were to go down a road without stopping the cars runs fine as long as you don't drop ti idle so that would rule out fuel.

Temp of fuel rail/intake seems to be normal. As long as you have pressure which means fresh fuel moving up into the rails I doubt its a "vapor loc" issue.

 

[Grant 302]

Could you borrow a friends TB for a test?

Do you have the stock PCV parts? or somebody you could borrow them from?

 

[Swiss Boss]

Thanks everybody for the suggestions.

I don't think it's the TB. When I monitor it with the computer, it seems it respond to the command.
If I stay above a 1000RPM there is no problems

The no start condition after it stall kinda steer me away from the bad TB too.

I leering toward a bad camshaft or crankshaft sensor. The problem is, I've got the PRS harness upgrade so it's not simple to swap sensors.
I'll will measure the resistance of the crankshaft sensor when the car is cold and then one more time when the no start occur. If that sensor read open it will explain the no start.

I did took it for a spin tonight and it still stalled. I let it warm up for 10 min, drove 5min and pulled in a parking lot, let idle for a minute then it stalled.
I had to wait 10 min before it would startup again and then I had to keep the RPM up otherwise it seems it would have stalled again.

I was monitoring the CHT on the computer and it matched my external water temp gauge so I know that sensor is good.

I hate when you got a problem and there is no code. So much stuff that could be wrong with all the electronic

 

[BigTaco]

Have you considered that it's possible the potentiometer on the throttle body may be malfunctioning? In other words, sending back info to the ECM that looks good but not physically maintaining the correct throttle blade angle after warm up?

 

[Swiss Boss]

I don't think so.

According to the schematics, there is 2 position signals. And I'm pretty sure if they are different from each other you'll get a bunch of codes. Basic redundant system for security, kinda like the return spring on a carburetor.

http://iihs.net/fsm/?dir=710&viewfile=024%20-%20Electronic%20Engine%20Controls%20-%205.0L.pdf Page 8 for TB signals

 

[Swiss Boss]

Well...

Went from bad to worse

So today I removed the crankshaft señor, cleaned it, measured the resistance between the pins (840ohms) and installed it back.

I went for a test drive, same as before, pulled in the parking lot, let it idle for while, won't stall.
Decide to go for a longer test drive, get on it a little (5-6k rpm) in 3rd, slow down to make a turn on a small road, downshift in 2nd (rev match).
Once I'm straight on that small road rev it to 7k let slow down by itself till 4500 then try to upshift to 3rd and won't go into gear. Try one more time very gently and nope won't go into ANY gear.

Pull over, clutch depressed, idle fine. Shifter in neutral but car still in gear (3rd I believe) so if I release the clutch car will die.

So I guess I've got a tranny to replace too.

 

[F.D. Sako]

It may be coincidence, but sounds like your clutch might have given up. I had a similar experience when my clutch hub failed (where the damper springs are).

 

[Swiss Boss]

Car is in the shop. They pulled the transmission out and it's locked in gear.
It's going to get shipped to Ben Calimer for a rebuild and stage 1 upgrade.

Since the transmission is apart I'll be upgrading the clutch and pulse ring.

Hopefully there is no more surprise and the car will be ready for my trackday at IMS.

 

[SPDBOSS]

Car is in the shop. They pulled the transmission out and it's locked in gear.
It's going to get shipped to Ben Calimer for a rebuild and stage 1 upgrade.

Since the transmission is apart I'll be upgrading the clutch and pulse ring.

Hopefully there is no more surprise and the car will be ready for my trackday at IMS.

Hello all,
Just back from 2 days at Watkins Glen, and my 2012 Boss is experiencing the exact issues described by Swiss Boss. I was excited when I found this thread, reading it and waiting for the solution to be revealed. Damn! Now I‘m thinking a new clutch and transmission?!! Well, those items are consumables eventually, right? I guess I’ll pick up where Swiss Boss left off and see if I can find a less expensive and less intrusive solution.
BTW, if I can stop and get the hood opened before it stalls, (let heat out) it continues to idle without issue. One other interesting note relates to the ignition ON audible chimes after a stall condition. . If 3 chimes, car will start and run fine. This is usually the case 10 to 15 minutes after the stall. If no chimes, car will not start. If less than 3 chimes and if it does start, it will be in limp mode. Does anyone know if the number of chimes have a fault meaning?

I have done the idle relearn procedure, but problem remains.

Thanks for any thought y’all.

 

[TMSBOSS]

The sensor at the rear of the engine which works with the pulse wheel could be dirty. This can cause symptoms similar to what you have when a relearn is not done for the pulse ring. Pull it out and inspect, if it’s dirty clean or replace.