crown vic intermittent shut down

[SnakeBit!]

2007 Crown Vic, P71, approx. 124K 4.6 2V. In May went to visit my son in Orlando and on I-4, in the middle lane of like an 8 lane interstate, the car quit. now that was an adventure at 65mph. lights on the dash on, no CEL, no codes when I scanned it.

Started up again after I got to the side of the road. got to his place, checked battery cables, negative was very slightly loose, hard to turn it but you could. tightened it up, drove all the way to the right the entire rest of my trip. nothing happened.

fast forward to august, has happened twice. once it first would do nothing, then it would crank and not start. other time, no crank. like no battery, except lights on dash on and radio, just like Orlando incident.

replaced the crankshaft position sensor, just in case. then the third time, after that it did it. no crank, all lights, etc. on.

tested the battery, battery showed low charge and dropped to 10v when cranking. Optima Red Top, second one as the first one only lasted two years. this one is 2.5 years old. rest of charging system all good. so I replaced the battery. waiting for the next time it almost gets me killed...always in busy traffic. car is not overheating, no loose grounds I could find, no frayed wires so far, never a CEL and never a code after the failure when I scan it. only way to see if anything I am doing is to drive the car and see what happens. getting old driving in the right lane all time!!! A/F ratio is always good. no prior warning...just stops. doesn't matter if stopped or while in motion. no consistency to it that I have been able to determine. not even time, as it was months before it did it again. then had done it about 3 times in the last month. another reason I am and did lean towards the battery. When the first one died, lights and all worked, just would not crank. no click no nothing which is what it is doing now when it does it. usually only lasts a few minutes then the car starts right up and doesn't do it again for a period of time.

Any ideas? I drove it to my daughter's Monday and back which was about 40 minutes both ways, no incident.

 

[cobrajeff96]

I had similar symptoms and all it was was a corroded body connection on the (-) battery cable. I sprayed it brake clean and wire brushed the crap out of it, tightened it as hard as I could with a 3/8" ratchet as it is a rather heavy bolt and thread. Never an issue since.

 

[SnakeBit!]

Thanks!!!!! that means a battery issue did create this for you. hopefully me replacing the battery, cleaning the terminals and tightening the crap out of it will do it.Thanks again!!!!

 

[cobrajeff96]

As long as you're sure the alternator is charging correctly.

In my case no battery replacement was necessary.

 

[96blak54]

Alternator charge/output are critical on the later modulars. Even if the alt produces 13.8volt when running with all electric accessories on. Even when the parts houses test the alt and claim its ok. The platform gets real finicky.

 

[cobrajeff96]

Just my opinion but alternators should be running at least 14v, but you're also kind of stuck with what you got with a traditional alternator where the voltage regulator is buried within the alternator casing and non-adjustable as well.

 

[SnakeBit!]

I don't have alt test equipment and so I have to go by what the test showed at Advance Auto and he said it was putting out more than enough.
It's a wait and see now game as I drive the car.
I appreciate everyone's input.

 

[cobrajeff96]

It's pretty simple actually. Any multimeter or voltage meter will take the reading. As long as the battery terminals show that 13.8v or higher with engine running and it holds that then the alternator is working. Of course if Auto Zone's test machine is advanced enough it will also be able to pick up rippling DC or AC leakage into the DC system. Maybe, I say. Never used their services myself so I can't know for sure.

 

[SnakeBit!]

the reader the guy had looked pretty sophisticated. I'm quite sure it would have told me anything in the charging system that was off. He performed a series of tests, engine off, on, load tests, starter tests, alt tests. tried a couple of other things and all said the Optima Red Top was weak. they don't last anymore. again, this is the second one in just over 4 years. a lot of money for something that doesn't last. I have a Marty tune in the car and he said also, the battery could definitely create my problem. I'm looking for anything in the event it comes back. Thanks!!!!!

 

[07GtS197]

Just an fyi, those cars use a Mitsubishi alternator which are pretty stout. I had one fail by way of a bad diode so it would drain the battery over night. And they are computer controlled. They do have some sort of voltage regulator but when these alternators are used in other applications without ecu control they default to like 12v or some low number.

 

[SnakeBit!]

Interesting. Thanks!!!!! I have two used spares just in case.......

 

[gcassidy]

I'm just gonna throw this out there because I had a P71 from 2010 to 2015, and it did the same thing. You’re probably on the right track with the electrical. But in my case, it just died while I was driving, no CEL, and then refired after a few minutes. Now you've probably already looked at this since you've been through the car a couple times, but in my case, a leaf had gotten inside the air filter housing behind the filter somehow. My mechanic says that happens every now and then when a filter is being changed outside. The leaf blocked the air flow enough to stall the engine, then fell, allowing the restart. It was damn hard to diagnose until we looked inside there. Just a thought. And damn, I miss that car!

 

[Todd in KS]

I would have a better look at the charging system. I have had several Red Tops and they have lasted at least 5-6 years. I had one that hung in there for 10.
An inexpensive multimeter is a good thing to have around the shop. Harbor Fright has them for as low as $7.99.
The cable ends are another place to look. You can get a battery terminal brush that has wire brushes for the clamp and the terminal for $4 also at HF. After you clean it, spray with terminal sealer. I have a can of permatex stuff that is purple (?).

 

[SnakeBit!]

Thanks, I understand what you are saying and appreciate the help.
I have had Red Tops over the years as well and always had good service life. however, the last one tested bad as I said at the 2 year mark and now this one at about 2.5 years. And now their warranty is only for 3 and as I recall, it used to be 5.
I was told by the owner of a well known shop that he used to carry Red Tops but no longer does due to the longevity issues now. he said they just don't last.

 

[I_LIKE_TURTLEZ]

Almost impossible to fix a vehicle that isn't broken, eventually with driving, it will stay broke. Sounds to me at a glance you have a problem between the ground and the battery.
More likely the issue is internal in the battery itself, I would still do voltage drop tests at each connection point of the body/engine grounds. You would expect to see 0v and the circuit needs to be energized.

Batteries are not the same quality they used to be post 2020, it doesn't matter which brand you buy or how much you pay, they're now all equally junk. Trust me on this.
The only way to truly test them is a carbon load pile machine, amps never lie but the digital testers we use now certainly do sometimes. Same goes for alternators.
Another thing about batteries is you can have your 12.6 nominal voltage, the vehicle will start just fine and then suddenly you're stranded with no warning.

If you're getting 13v+ with the vehicle running & the battery dash indicator isn't illuminated, I wouldn't suspect the alternator.
Since you really can't do anything but throw parts at it for now, I'd start with a new battery, I think you have a cracked internal plate making intermittent connection but that's just a hunch.

 

[SnakeBit!]

That all makes sense and I surmised as much without the knowledge you obviously have. I just looked at everything it was doing and came to a conclusion and have already replaced the battery. Thus far, it has not returned, however, with how random it was, I am cautious.

Thank you for all you provided!!! I do appreciate it!!!! Hopefully my guess and your hunch is right!!

 

[SnakeBit!]

well, after almost three months trouble free, I thought I was about ready to take a victory lap and I went to pick up my son from the train station and the way home on the interstate.....it quit.....again. no prior warning like always, just off. did throw the wrench icon on the dash this time, but still no code on my code reader. I have someone with the high tech stuff that I am going to ask to do a deep dive in the systems and see if anything shows up. I suppose something in the drive by wire...one of the sensors or the throttle body itself could be the source. or something on the bus, a cracked wire that is exposed to the atmosphere or extraneous electronic noise. hopefully not that as that could be a nightmare to find. I'm also going to hopefully get a code/can bus reader and leave it plugged in, in hopes that if it does it again, it will catch something in the data.

 

[cobrajeff96]

Can't say for sure myself, but a bunch of people have told me over the years that Optima got bought out by some Chinese company and ever since they've been shite. I owned an Optima red once back in '04 and it carried that car all the way until 2010/2011. Replaced it with another red top thinking it would be a no-brainer and it lasted maybe 3 years. So I do have firsthand experience with the degradation in quality from the brand.

I must say though that ever since I switched to a Varley racing batter it's been smooth sailing. Though, it's obviously a 100% custom solution so it's not for everyone. That, and a standalone Noco lithium starts the car. My car is weird.

Have you done any battery tests since this latest episode?

 

[SnakeBit!]

Thanks for the info!!
No, no battery test yet as it just happened two days ago. Hopefully a battery of tests (no pun intended) will be done on Saturday and I am praying to find something to latch on to. In the meantime, a new throttle body that is already equipped with a new TPS will go on tomorrow as well as I may be replacing the connector to the mass air sensor as it is looking a little rough.

 

[07GtS197]

You’re probably right with it being in the drive by wire system somewhere with the wrench icon popping up. Could be the throttle body motor is going, intermittently losing voltage and closing while driving.

On a side note, how much do you think you gained from Marty’s tune? I’m thinking about one for my 09.