only 12 on v-meter - shold be 14? - any ideas?

[ronr]

FL-70 3126B - this truck been sitting for 2 years - fired up fine - but the above bothers me - any ideaswelcomed - thanks

 

[guido4475]

Put a voltgauge to the alt and see what it reads.it should be just a hair more than the gauge reads.if it ever does not want to start but only makes a clicking noise like when a ford soleniod goes bad, look on the firewall, passanger side. there is a soleniod there with 4 wires going to it that will go bad. water drains on it all of the time. i kinda have a small problem with my van, the alt is charging, dash gauge shows charging,and i tested the alt and it shows 14.7 volts, but the battery light will light up once in awile on the dash. figure that one out!!

 

[miker]

Put a voltgauge to the alt and see what it reads.it should be just a hair more than the gauge reads.if it ever does not want to start but only makes a clicking noise like when a ford soleniod goes bad, look on the firewall, passanger side. there is a soleniod there with 4 wires going to it that will go bad. water drains on it all of the time. i kinda have a small problem with my van, the alt is charging, dash gauge shows charging,and i tested the alt and it shows 14.7 volts, but the battery light will light up once in awile on the dash. figure that one out!!

I've had alternators in the past that tested fine but had a bad diode in them or even a weak diode, it eventually went out.

 

[greg334]

OK assumptions -

1 - you didn't keep the batteries charged during the time it was parked.

2 - you didn't check the cables on the alternator before you started it.

Thoughts -

Batteries need replacing unless you did #1

OR

You may have one bad battery that is drawing a lot of current and it needs replacing

OR

The cable from the alternator to the battery (starter?) needs to be replaced or just the end. I replaced the end at the alternator and it fixed a lot of problems.

OR

The alternator took a dump while it was sitting but doubtful that happened.

OR

the thing needs to run for a while to charge everything up.

OR

your glow plugs are stuck on, in that case you will end up seeing the voltage go up as they burn out and you will need to replace all 6 of them.

OR

your fan belt is gone....

 

[bluejaybee]

I can attest that a 3126 has no glow plugs. They have an intake heater. And agree that the possibilty of one bad battery is a good place to start looking.

 

[greg334]

OK Ok I don't have a kitty cat engine, I have a real junior truck engine and it too has a intake heater. I should have put that in the assumptions section of the post.

 

[Slo-Ride]

Charge &Test each batt,,,load test each batt,,
check out-put of alt,,,
check gauge with known gauge that works,,(loose ground wire on gauge will show low voltage @ times)
Check all grounds and ground straps,

If no of the above helps,,,,park in my driveway,, for 50hr Ill get it to read 14volt

Assumption: Your reading low voltage with ALL accessories off????

 

[ronr]

Thanks guys for your thoughts. I should tell you that I just put in 3 batteries that tested 600, 750, and 800 if I remember right. Hopefully that would rule out the bad battery as a cause. I'll take a check on that 4-wire solenoid possibility. Other than that maybethat 600 battery the problem? I don't think connection issues would be a problem as just been sitting and was fine before. Can alternators corrode causing underperformance over time? LOL - course what do I know? I like the idea of"needs to run for awhile to charge everything up". That would be the best! I idled it for about 20 minutes and had to shut it down before road test due to a corroded and leaking coolant reservoir. So need to replace it before further ado. Again Thanks and any more responses appreciated! I'll get back to you.

 

[bluejaybee]

I don't think connection issues would be a problem as just been sitting and was fine before. Can alternators corrode causing underperformance over time? I idled it for about 20 minutes and had to shut it down before road test due to a corroded and leaking coolant reservoir.

Sitting out of service is when the connections go bad. Just as the reservoir corroded, so do electrical connections. We are just giving you the things you might check. But, in my opinion, the most important thing is the exact voltage your alternator is putting out. If you are low there, then I would be looking at it first. And are you having starting problems. Or are you basing it on the gauge reading? I had a Sterling with a 3126 that the digital readout said 13.2 volts and it never would go higher. Multi-Volt meter showed alternator was putting out 14.3, i was not having any problems, so I rolled on down the road.

Why 3 different size amp hour batteries? I personally wouldn't have done that. Just curious. Were they used?

 

[ronr]

Thanks again BlueJay and all. I'll check that alternator output and report back. On the 3 diff battery ratings - I bought used ones at local auto parts store w/a 1 yr guarantee and no prorate to save some bucks at this time. Hope not a mistake. If/when I get back on road - I plan on taking em back and buy new ones. Good luck out there all.

 

[ronr]

well - borrowed a reliable volt meter and did checks this morning - bad news - alternator output Zero (did not register). Batteries checked 12v w/truck on and off. I did same check on my pickup and got the 12v and 13.5 - 14v on both battery and alternator. Darn - need to remove alternator now and I'll have tested at ato parts store before buying a new one. Thanks guys for ure help. Good luck out there!