Died unexpectedly. First thoughts? (1 Viewer)

[e9999]

It's been 2 times now that the battery was completely dead on the truck after several days of no driving. The first time, a few weeks ago, I thought it was because the door was not properly closed. The second, yesterday, there was no indication of a door being the issue. I charged it up a bit, it started fine. A few minutes later, while idling at an intersection, about a mile / 3 mins away, it died. Refused to start back up as if there was no power at all. Not sure but dashboard may have been dead. Finally started again after several tries and made it back home. Recharged the battery, left it overnight. Held charge just fine by morning (12.87V after 8 hrs). I measured the parasitic draw and it's negligible, below the resolution of my clamp meter I think, about 50mA maybe. Battery is less than 2 years old. Connections appear tight. May or not be related: had a rat nest in the engine bay a few months ago, but drove fine since, and I see no evidence of chewed wires in the engine bay.

So, my gut feeling: there is an intermittent short someplace that may discharge battery and kill engine / all electrical system.

What would you look at first? TIA.


added: in retrospect, I think that some / all of the no-cranking could have been because I was still in gear. Not sure.

 

[YotaWagon]

First thought: A lot of people have a parasitic draw from the port installed rear DVD player that can be solved by removing the in-line fuse below the glove box.

edit: Second thought: I'm a bad reader and noticed you said the draw was negligible.

 

[awesomeissquid]

If it died while the engine was on wouldn't that mean the alternator was not functioning properly?

 

[AlpineAccess]

When it died while idling, was the starter turning over normally or was it barely going when you tried to restart it?

How old is the battery?

 

[e9999]

^ After it died and I tried to restart, nothing happened at all, no cranking is what I recall. But TBF it may have been because I was still in gear, not too sure. (Added something to the OP about that.) I also have this impression that the dash went dead, but that could have been just looking at the Tach and extrapolating. I believe it may have later started once and then died again, but not too sure, this happened very quickly in the middle of traffic and I was scrambling to prevent an accident. I think maybe 5 or 10secs happened while I was talking to somebody, tried again, in Park or N that time for sure, and then it started and kept going. Battery is less than 2 years old. Dang, I wish I had paid more attention to the dash. Battery still at 12.8V. I just tried it now and it started just fine.

^^ I would think that even if the alternator has an issue, it would keep going for a while on the battery alone. May be wrong about that.

So, what could have emptied the battery and later killed the engine? Surely, it's not a coincidence that the 2 happened the same day.

 

[awesomeissquid]

Interesting. Yea with the alternator down, the battery should support the engine for a little while at least. It is possible if the alternator was wonky and you were already on battery that maybe it fully died, but that doesnt hold up since you were able to restart and drive away a short while later. What about the fuel pump, has it been replaced?

 

[e9999]

no, original fuel pump.

Started several more times just fine and kept idling. Battery at 12.8V between starts, alternator gives 14.2V when idling.



Is it possible that if the battery is completely dead (as in 2V or so), some settings in the ECUs could have gone wonky and it takes a while to reset properly and it may have hiccupped on the road?

 

[medtro]

Same thing happened to me and it was bad alternator. I was able to drive for about 1 mile since the problem started and before it was dead completely. It acted like a bad battery, didn't want to crank. It would start with a jump, and it stalled immediately when jumper cable is disconnected. Put in a new alternator, didn't even have to charge the battery and it started right away.

 

[e9999]

Alternator, eh? Interesting. Why do you think it would kill the engine and not crank? Was the battery very low?

But, I don't know how that would explain why my battery went dead after only a few days, maybe a week, of no driving, though. Maybe a short in there?

 

[abuck99]

‘03? Current Mileage?

Ever replaced fuel pump? Fuel filter?

Curious what were ambient/OAT and Coolant temps when this happened?

 

[medtro]

Alternator, eh? Interesting. Why do you think it would kill the engine and not crank? Was the battery very low?

But, I don't know how that would explain why my battery went dead after only a few days, maybe a week, of no driving, though. Maybe a short in there?

My battery was not low. I took the old alternator to two chain stores for testing. Both of them said there was a short. I asked them where was the short, they couldn't explain that to me. They proceeded to ask for my vehicle information again, trying to sell me a new alternator. One of them also told me my alternator was old.

 

[e9999]

^ a short? Dang...

^^ yes, '03 and something like 160k. Original fuel pump and filter. Coolant was probably barely above ambience which was not that high, maybe 80F.

 

[abuck99]

19yr old FP- I’d start there.

 

[awesomeissquid]

19yr old FP- I’d start there.

I agree with fuel pump. I think if it was a short in the alternator you would be having a more constant issue.

 

[Weedhopper]

You could have a battery gone bad. They do. Try swapping in a different battery and see what happens. If it’s an Interstate battery that increases the likelihood of a bad battery.

An old Blazer had the same problems you are having with an Interstate battery and it died on the road too. New battery fixed everything.

 

[e9999]

New development:

I went to check the truck yet again. Battery is good, starts just fine. But I checked the Nav system and what I saw is that it shows the distance from last refueling to be *1* mile. Now, when I drove it a couple of days ago after recharging the battery, I did 1.4 mile before it died. Then I drove it back, another 1.4 mile. That suggests to me that there was indeed a full-blown dead electrical system event right then that may have reset the mileage indicator, which is why it shows only 1 mile (about the distance driven back). That would also suggest that it was not a fuel pump event. And that somehow the notion I have that the dash was dead during that forced stop may have been true rather than a figment of my imagination as I was starting to think.

What say ya?

 

[TriumphToys]

Had similar problem w/previous '01 LC, 282k mi.. Fuel Pump Relay, Fuel Filter & Pump were intermittent issues, Voltage Regulator on Alternator, & Battery had a dead cell. Much chasing, but in the end we nixed it. Was going to say starter solenoid, but You said in gear/not sure. You should have battery tested. A dead cell can still throw a 12v+ after charging, but it no longer has cranking AMPS? As for Your "dead electrical event" absolutely, Nav system resets @ anything under 3-4v. If Voltage Regular's on the fritz(no disrespect to anyone that shares that name), it can fry relays, wiring & battery (along w/lots of fuses). If Your voltage isn't consistent on alternator, that's probably the source of all Your grief?

 

[medtro]

New development:

I went to check the truck yet again. Battery is good, starts just fine. But I checked the Nav system and what I saw is that it shows the distance from last refueling to be *1* mile. Now, when I drove it a couple of days ago after recharging the battery, I did 1.4 mile before it died. Then I drove it back, another 1.4 mile. That suggests to me that there was indeed a full-blown dead electrical system event right then that may have reset the mileage indicator, which is why it shows only 1 mile (about the distance driven back). That would also suggest that it was not a fuel pump event. And that somehow the notion I have that the dash was dead during that forced stop may have been true rather than a figment of my imagination as I was starting to think.

What say ya?

Did you lose any saved radio stations and audio settings? Was the trip A/B meter reset?

 

[e9999]

no and no, but I would not expect that to be the case when disconnecting the battery either. Should I?
Perhaps oddly, I ran an OBD scan on the beast and there was no code and surprisingly all the monitors were Ready. Did not expect that.


Wait a min, if the radio stations etc would disappear with a battery disconnect but didn't, is it possible that it was a fuel sender / fuel pump assembly shutoff that reset the fuel mpg? Back to the fuel pump as culprit then?

 

[medtro]

no and no, but I would not expect that to be the case when disconnecting the battery either. Should I?

Yes and yes on my '03.