Just replaced the alternator a year ago, could it be any other issue?

Thanks.

 

Are you measuring amps or volts? I would have the batteries tested separately ( completely disconnected from one another ) and have the alternator bench tested.

 

Volts, batteries are both 6 months old.

 

It doesn't matter how old or new anything is. If you don't do the testing you'r guessing and throwing money at it.

 

Oh, I'm going to have it tested. Iv just never had an alternator/battery last only a year...u

 

11.77 doing what. if the truck is just sitting idleing thats probably all it needs. if its 11.77A at 13.8 to 14.2 volts your good. the regulator will only allow the alternator to put out whats required. Turn on every thing electric plus the cigarette lighter and check amperage and voltage. If it puts out high amperage at 13.8 to 14.2 you should be good to go.

 

x2, plus if you measure immediately after starting on a cold day, the glow plugs will be on using lots of AMPs, thus drawing the measured voltage down (thus 11.77 Volts would be normal - at that moment).

So, start your truck, give it a couple of minutes to turn off the glow plugs, THEN measure your VOLTAGE. it should be 13-14.. Turn on your headlights, A/C, rear defrosters, heated seats, etc. and while idling your voltage will likely drop close to 12v - with a stock alternator..

But, this doesn't tell you if 1 of your batteries has a bad cell... So, you need to go to your local auto parts store and have them LOAD test EACH battery.. You need to disconnect the ground wires from BOTH batteries so they are actually load testing EACH battery isolated from each other - and w/o any load from the vehicle..

Think of this like taking your blood pressure.. did you just wake up or have you just walked up a flight of stairs? your BP will be totally different..

 

Truck started weak this am, usually it's between 13 and 14, drove 20 minutes to work with no change on the sct guage, I'll be stopping by the auto parts store on my way hone to get the batteries tested.

 

Next question, will I damage anything driving it to autozone pulling 11.77 volts?

 

That low of voltage is not doing your ficm any favors.

 

Absolutely not, FICMs do not play well with voltage that low. You're on borrowed time with voltage that low.

If you have another set of wheels or can hitch a ride, remove the alternator and have it tested. If it fails (sounds like it has) opt for the large case 140 amp alternator as it's much better than the stock, dinky small-case 110 amp alternator.

Regardless of the situation, both batteries must be pulled and slow charged so the alternator doesn't kill itself charging the batteries. Keep in mind, it'll do the job, but it will take a roadtrip with no accessories on to do it properly.

 

It was the alternator, showing 13.75 volts driving down the road. What is everyone using to release the tensioner? I bought the kit they sell at the auto parts stores, but that didn't work...ended up having to muscle the belt up around the pully, was not fun.

 

There is a kick-stand under the tensioner. Pull straight back on the belt and with assistance, lift the stand. Belt comes off easy then and after the alt change... just pull on the belt again and the sick-stand will snap back to its original position, it's spring loaded.

 

Well crap, next time should be alot easier, thanks for the help.

 

If your pulling the belt, you need a helper to lift the stand as it takes two hands to get enough torque to pull it slack. I lifted the stand with a long screw driver, but holding the belt tension with one hand about pulled my arm from the socket and almost put a dent in the truck fender (braced myself) as it tried to pull me into the engine bay.

Sounds funny, but I paid for a couple days with a sore shoulder.