Intermittent Failure!!!!!!!!!!!!!

1bad4.6l

1bad4.6l

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Ok the car died on my wife today. I figured fuel pump. I got the car back to the shop via the truck and it fired right off. So I banged the tank..... still running, Let it run and 30 mins later it died. So I tried to restart...... it did start let it run a little longer and it died finally wouldn't restart. So we checked the spark.... dead at each coil..... All of a sudden while checking the fire it started. and wont die now I aint driving it home tonight and gettin stranded, I'm gonna have to get some gas to waste so I can get this thing to die, I also had an intermittent batt light While it was running and tested the back of the alt it was the same 12.36 there as the batt, then it went off and was back to 14 volts at both that was odd now wasn't it. Note the car was running the whole time I was testing the alt. I'm leaning towards crankshaft pos sensor. Until the batt light came on. Now I'm slightly confused.. Cause it has a brand new cobra alternator from ford dealer.


I need more gas to run more tests, and have to get a ride from the bossman home. I will not be here to reply tonight but will be checkin this thread first thing in the mornin Thanks for all the help in advance.:confused:
 
You dont need more gas to run tests, you need a fuel pressure gauge! :) That will rule that much out. Sounds like it could be a number of things, possibly a bad ground causes all the issues.
 
I have one and pressure is great, thats why I dropped that part of it in my description, and it's good when it wont start either, but ground.....yes yes that could be it and would help the alt issue also, but keep em comin if you have em.
 
My money is on it not being the right alternator. If it were the camshaft position sensor, it would've thrown a code. Was this a problem that has be ongoing, or did it just hit all of a sudden?
 
GMAN, I have never gotten a code on crank position sensor, only on the cam position. My understanding is that once the crank position sensor is used to start the car, its no longer referenced and the cam position sensor takes over. I am not 100% sure, just something I recall reading.
 
I doubt its the alt seeing you just got it two months ago from Max.
I would check pressure at the rail like Unity said.
If that checked out good then I would check the alt. to make sure its pulling 14.+
You could be one of the few that got a bad one...I think Max has had only one returned.
When my alt went south it gave off a nice dash light show before the car died.
 
unity said:
My understanding is that once the crank position sensor is used to start the car, its no longer referenced and the cam position sensor takes over. I am not 100% sure, just something I recall reading.
Click to expand...

It's the other way around. You can unplug the cam sensor on a running engine and it will continue to run. A bad crank sensor (or harness) will result in a no-start or the engine will shut off.
 
unity said:
GMAN, I have never gotten a code on crank position sensor, only on the cam position. My understanding is that once the crank position sensor is used to start the car, its no longer referenced and the cam position sensor takes over. I am not 100% sure, just something I recall reading.
Click to expand...


close, the cam sensor is only referenced at start up

correct the crank sensor generally doesnt throw a code

crank sensor is full time, otherwise a steeda timing adjuster would only adjust your timing at start up?

lolz
 
Very helpful stuff guys, thank you. Yeah I didnt get the usual ABS Batt light crazy no heater usual alt show so I think that stuff is irrelevant. But I am leaning towards a ground issue. This totally blows cause now I have four cars in the driveway [mark is the only one tagged] and I'm driving my dads truck, well me and the wife are sharing it to get to work.:cool:
 
Update- All of the grounds look good, Wiggled the main cluster of power and ground goin to motor and still idling, Wiggled cranksahft wiring, still idling, This sucks balls.:confused:
 
1bad4.6l said:
I also had an intermittent batt light While it was running and tested the back of the alt it was the same 12.36 there as the batt, then it went off and was back to 14 volts at both that was odd now wasn't it.:
Click to expand...

one of the few times my car had "ever" died while driving it was battery/alternator related.

When you tested the battery did your air ride pump turn on (if you have one)
OR was the Electric Fan running?

both are very large electricity hogs when they are new, once they start to get old and tired they can easily overwhelm a marginal battery or alt.

can you ask the wife what what happening when the car died?
had she just exited the freeway?
^ that is when mine did it, I'd just pulled off the freeway.. the tired compressor kicked on..and crapped my alternators output..about 30 seconds later all kinds of goofy stuff turned on and off (climate control ect)..then the car died....poof

The next day, the alternator was putting out 14ish V and while I was watching it.. the air pump kicked on and the Volts dropped down to low 12's just like you saw.

"just a thought from the far side"

Since these cars are "so heavily dependent" on electricity, there is no "irrelevancy" when issues arise.
 
When it died on her she was driving in a 25 mph zone and probably goin like 30. And I'm airride free on this car so that wasn't the issue. The fan may have been runnin but now the damn thing won't die. I am having no luck recreating it. I got it to die yesterday and it lost spark when it died, not fuel. So i'm thinkin of throwing a csps at it for $20.00 and see what happens to her. The car has been running all morning drove it around out back left it in gear on the rack with the cruise set IT WON'T DIEEEEE AGHHHHHH!:mad:
 
Just a thought

Does that car have a IAC on it like the LS's? If that thing starts to fail, you get some real starting problems, also does that car have the MAF sensor? It maybe dirty or failing, another cause of starting issues. A large vacuum leak could also create some problems.
 
My stang would do the same thing. Turned out I had a bad ground by the ECU causing it to blow ignition control modules..
 
If you lost spark when it died it was the crank sensor or harness connection to the crank sensor.
 
Thank you driller, to my best recollection the crankshaft pos sensor is the only thing that tells it to spark? this doesn't sound right as I say it. There is an ignition control mod right? Why amI asking this I'll just look at alldata.
 
1bad4.6l said:
Thank you driller, to my best recollection the crankshaft pos sensor is the only thing that tells it to spark? this doesn't sound right as I say it. There is an ignition control mod right? Why amI asking this I'll just look at alldata.
Click to expand...

Yes there is an ignition control module as well.. pull the cover off the drivers side strut under the hood and you'll see what is called the EDIS module
I beleive it stands for "electronic distributorless ignition system"
 
ICM...

icm.jpg
 
check that the battery has a good clean ground connection also check for a dead cell sounds dumb it happens
 
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