Sporadic Start Issue... Alternator? (1 Viewer)

[thekitchensink]

Hey all,

Wanted to get your thoughts on this. I made a quick stop (maybe 3min total) the yesterday and when I came back to the 80, it wouldn't start. All auxiliary would turn on (lights, fan, etc), but the engine would not turn over (just clicked).
I came back to it after about an hour and it started right up no problem. After reading the "Emergency Troubleshooting Procedures - FAQ Item", I think I need to replace my alternator (as far as I know, it's original). My battery is a standard Autozone (EDIT): Advance Auto parts unit... and it's about a year old.

The truck has started ever since I first had the issue (couldn't replicate it). I took some readings from the battery today:
Engine off: 11.95v
Engine on with no accessories (lights, a/c, heat, etc): 13.47v
Engine on with accessories (lights and A/C): 12.25v

From what I'm reading the voltages should be closer to 12.5-12.8v with the engine off, and 13.8-14.2v with it running.

Anyone had this issue before? What fixed it?
Also, if I do replace the alternator, what should I do while I'm in there?

Thanks!
-Graham

 

[BILT4ME]

Your symptoms match pretty close to what mine were.

I ended up replacing my battery as well, but yes, the alternator needed to be replaced.

Also check your starter, fusible links, and cables. It may be time to clean up the ends of the cables or install new ones.

WIIT things:
Alt/AC belts.
Head Gasket.

 

[CJF]

The truck has started ever since I first had the issue (couldn't replicate it). I took some readings from the battery today:
Engine off: 11.95v
Engine on with no accessories (lights, a/c, heat, etc): 13.47v

Reads more like a bad battery to me. (Yes, I know it's only a year old.)

 

[thekitchensink]

Also check your starter, fusible links, and cables. It may be time to clean up the ends of the cables or install new ones.

Cables are newish (PO did them right before I bought the truck). Fusible links are waiting to be shipped from Wits End. How would I go about checking the starter?

WIIT things:
Alt/AC belts.
Head Gasket.

Belts are in the same order as the fusible links. Lol... HG will be done soon. But I need to get this thing back on the road.

 

[BILT4ME]

Reads more like a bad battery to me. (Yes, I know it's only a year old.)

That's EXACTLY how mine started out. The less than 2 month old battery wouldn't hold a charge. I couldn't hold voltage at a stop light.

Replaced the battery. Didn't help.

Replaced the alternator. Sort of helped.

3 days later my truck wouldn't start. Replaced the starter.

Problem solved.

 

[thekitchensink]

Reads more like a bad battery to me. (Yes, I know it's only a year old.)

I might take it to Advance and have them check it.

 

[Enders]

I had a similar issue with my 96. Flatlined a year old battery. Power to everything until turn to start, then click followed by complete loss of electrical power. Wait and hour and you get power windows/locks/headlights back, then turn the key and everything’s dead again.

I first thought it was the fusible link, but it ended up being the cable running to the starter and the main engine block ground line. They run together and the one I replaced had lost all heat protection. Add a little bit of ATF from replacing the power steering lines and it must have found a way to short. Battery was down to 1v when I tried to start after replacing it.

New cable, new 31M AGM Duracell from sams club for less than $200, no starting issues since.

Good luck, and report back for posterity!

 

[thekitchensink]

Reads more like a bad battery to me. (Yes, I know it's only a year old.)

That's what I thought too... but doesn't make sense that voltage would go down to 12.25v and not come back up to ~13v when I turn on headlights/radio/etc.

I'm ordering an alternator and starter from RockAuto (remanufactured Denso units) ... and I'll have my battery checked when I get back in town on Monday. I'll report back what I find.

 

[BILT4ME]

That's what I thought too... but doesn't make sense that voltage would go down to 12.25v and not come back up to ~13v when I turn on headlights/radio/etc.

I'm ordering an alternator and starter from RockAuto (remanufactured Denso units) ... and I'll have my battery checked when I get back in town on Monday. I'll report back what I find.

Oh yeah, the other thing in there too..... Do you have a factory alarm? (RS3000) Mine started a regular battery drain as well about that time so I ripped out the alarm.

 

[thekitchensink]

Oh yeah, the other thing in there too..... Do you have a factory alarm? (RS3000) Mine started a regular battery drain as well about that time so I ripped out the alarm.

No factory alarm... I think the PO ripped that out.

 

[thekitchensink]

Replaced the alternator and I think that solved the issue. It's been 3 days since I replaced it, have not had an issue since (the CEL light also went off... although I don't think it's related).

Old vs. new. The bad alternator looks like it is from '07

 

[thekitchensink]

Thanks for all of y'alls help!