I finally got my truck that went in the pond last year up and going (I thought) I finally completed almost everything I needed to and noticed that my volt meter wasn't showing any charge even with the batteries up. I figured I fried the alternator when the truck went in the drink, no problem.... I put a new one on and still the same thing. You can start the truck if the batteries are charged and everything will run like it is supposed too (until the batteries go dead) The gauge shows just a little under normal operating range (8 volts I think) for about 15-20 sec than goes flat. I know the alt. is good, and I am pretty sure the meter is correct too so.........Is it in the regulator in the PCM?? Dirty connections?? I can't seem to figure it out.

ALSO...... When the truck runs for even a little bit the fuel tank builds up a lot of vacuum pressure, when you take the filler neck off it sucks more air in than you can imagine! Any ideas on whats causing that?

Thanks in advance,

Tom

 

you can have the alt tested to confirm that its good or bad, most places do it for free, you can hook up an external voltage regulator, do a search there are posts of how to do it, as for the Vacuum in the tank, are you sure its not pressure,? either way the fuel cap can be faulty or the tank vent, if its pressure (I think it is because you said it only needs to run for a short period of time) then the most likely cause is a loose injector hold down or bad copper washer.

 

Was that the 02?

First, check out each and every fuse, since the PCM controls the ALt. charge, any number of things could be goofing you up. Try scanning it and watch for things that might tell the PCM to not charge, such as no RPM to the PCM, etc..

If you are sure everything else works, you could always just go to the external Voltage Regulator setup as well.

 

vacuum pressure???????????? impossible! tank vent is plugged

 

Sorry I was mistaken it wasn't vacuum pressure it was just pressure, probably involving the hold down clamp or a washer as was said above. I am going to tear into it today.

Thanks for the tips!

Tom

 

Large fuse from alternator at pdc where large wire comes in from alternator.