bad batteries?
 

so i started my truck up, it started up like a champion. i drove it maybe 15 - 20 minutes and shut it off. ran into the store came back out and it wouldnt start. it would crank but wouldnt fire. i let it cool down and still couldnt get it to start. so i ended up having to tow it home. :argh: what an embaresment. but i then took it home tried jump starting it and that was a complete failure. so i went and bought a battery charger charged the batteries overnight and it started like a dream agian. i drove it around for a little while and turned it off and it started right back up. i started and shut if off numerous times and it still started like a champ. so i decided to go four wheeling 30 mins from home. took it to the park unloaded the four wheeler and rode for about 3 hours. went to leave and same thing it would crank but wouldnt fire. so i put the batteries back on the charger and sure enough it started back up. so with it running i took a meter reading right off the batteries and i was getting 20.4 volts so i know the charging system is good. but how can i know for sure if its the batteries. i keep seeing people say that they get theres load tested. but where can i get them load tested at? will my local auto zone do that for me?

another thing ive been trying to find is how picky are these 6.0. ive been told they are super picky with the amps and volts. what at what point are they no good? im about to cross over to the cummins side of things. this powerjoke is killin me with cost of fixes lol

thanks in advance guys

Unfortunately getting a cummins wont alleviate a dying battery or two. I haven't seen any diesels that don't use batteries...

Autozone can load test them for you. I'd highly suggest bringing them there, not sure how in the name of anything holy you managed to get 20.4V off a system that should be in the 13-14V area. Testing them running wont tell you much anyways, have someone crank it while you test it. See what they drop to. Or just bring them to autozone or advanced auto, some place like that, they'll usually test them free of charge. If one is bad, replace both.

that 20.4 was with the truck running. unles i got a bag regulator in the altenator. if i can get it to start agian i will check again. that or its just my super walmart special multimeter. i plan on taking them both and getting them load tested

Good call, let us know how you make out. At no point should they ever be running that much voltage.

ill have to try and use a good fluke from work. i was wondering when you said that is there a diode somewhere in the system that you know of that could have failed? i know a failed diode acts as a short (doesn't do its job anymore)

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S I must went and got the batteries tested and they both meet or exceed that standards. When I got back it started no problem. I'm starting to lean towards glow plugs or glow plugs relay. I know it's getting fuel I've checked that and I just did the fuel filters about a. Into ago so now what

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Also after I got back from the auto parts store I took it for arise long enought to hear the tranny and oil up to normal operating temperature. About 30 mi s later I tried to start it and it wouldn't start so I'm now to a hot start problem

That wouldn't be a glow plug issue if it's not starting hot...

No hot start is usually a high pressure oil leak. This can be monitored easily, or you can hook shop air up to the oil system and listen for leaks. You would need an extra IPR pig tail so you can direct wire it to a battery to command it closed 100%, otherwise the air just leaks out there. That, or put it on a scanner and monitor ICP desired and ICP actual.

The STC fitting is quite common in the 05+ trucks and cause a no hot start. It's $38 or so.

could a ipr valve cause this no start while hot porblem