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Can not jump start

I have a 2003 E450 Ford truck based C-Class motorhome with a 6.8 liter V-10. My truck would not start, and could not be jumped by two AAA tow vehicles. The truck was towed 15 miles to a store that sold batteries, and fired up without problems after a new battery was installed. My local Ford dealer says they have no problems jump starting Ford trucks. Other than the V-10, why would one be unable to jump start this truck?

Because the battery was toast. It was so dead it basically created a dead short in the system. Another possibility is there was a bad connection at the terminals fixed when the battery was replaced.

The connections looked clean and fine at the terminals. I am not sure what a dead short is? Why don’t the AAA tow guys unhook the cables from the terminal and jump directly to the cables, taking the battery out of the equation?

Ever see a loose positive cable touch a ground? Every see lightning in a bottle?

Plus, your 2003 needs to have the battery attached to prevent electrical spikes that can damage the ECM. On these computer-heavy newer cars, you never disconnect and connect battery cables on a running engine. Chances of frying an expensive electronic module are quite large doing this. The AAA guys know better than to do it.

I agree with the previous posts. You can’t jump a vehicle with the battery out of the circuit for many reasons. If the battery is bad then you have to replace it.

As others have said, bad battery or bad connection to the battery. This is not at all unusual. Whatever it was, problem solved now. Drive on.

" Why don’t the AAA tow guys unhook the cables from the terminal and jump directly to the cables, taking the battery out of the equation? "

Because it usually is not a problem. In your case I would guess your truck had not been used for some time. Un hooking and re-attaching cables takes time. time=$

If I am right, and you don’t drive this truck very often, it might be a good idea to disconnect the battery when it is not going to be used for some time.

The above comments really don’t explain the events. Can anybody give any intelligent comment to my situation?

I doubt that anyone will be able to explain the event because no one was there and you haven’t given very much information.

In fact, all you said is the truck would not start. Well, there are many ways that a truck “won’t start” and for any of those there can be more than one reason.

Perhaps you never had a battery problem. Perhaps, instead you have a dead spot in your starter, or a starter solenoid that is showing first signs of failure. Perhaps you have a neutral safety switch that is showing the first signs of failure. etc. etc. Did anyone ever test the battery? Well we don’t know because you didn’t say.

And all of that is just assuming that the truck wouldn’t crank. Some people think that if a vehicle cranks but won’t fire up a jump start might help - well, if it cranks then a jump start is irrelevant. Maybe you know this, maybe you don’t. Who knows?

All anyone here knows is that your truck would start - but we don’t know what that means - nor does anyone know what the AAA people did or didn’t do.

I do know that you absolutely do not disconnect the battery and jump straight to the cables. For one, you will fry things. For another, what would that even solve?

The above comments really don’t explain the events. Can anybody give any intelligent comment to my situation?

Actually, they do and the worrisome part is, you’ve already recieved the intelligent descriptions of the potential causes and reasons why they shouldn’t remove your battery and jump start the engine. Insulting the people who tried to help you isn’t going to enamor people into posting again or anyone new to chime in to help explain it “in layman’s terms”.

In answer to the questions posed by cigroller, the engine would crank but not turn over. It cranked more strongly when a jump was attempted, but not enough to start the engine. I was told by an earlier responder that the dead battery caused a “dead short” in the system. What is this and why can’t it be avoided by taking the battery out of the circuit? The AAA guys just hooked their cables to my battery terminals. Why would attaching their electrical system directly to my battery cables, without the battery, fry the system? The amps coming out of the AAA truck’s alternator are not frying their truck’s system?

Crank and turn over are the same thing. I assume that you mean cranked/turned over but wouldn’t actually fire up. In this case its actually unlikely that you needed a jump start at all. A jump start is what you do when the battery doesn’t have enough power to crank/turn over the engine. So your battery had no internal short which would be where +/- plates come into contact for some reason.

So the most likely reason that the jump start didn’t work is that it was irrelevant to the actual reason that the truck wouldn’t start.

Why I’m helping you after you insulted everyone, I don’t know.

Still did not answer the questions I posted. A new battery has fixed the situation with no problems starting since. Why is it thought that the jump start was irrelevant?

Did not see the link to Thanks.

Why is it thought that the jump start was irrelevant?

Because after much prompting you told us that the engine cranked, which means the battery was working.

As for why the new battery fixed things, it probably didn’t. But towing it 15 miles might have, because that might have knocked whatever worked loose (temporarily) back into place.

Doesn’t your RV have a boost switch that connects the house batteries to the engine specifically for situations where you think you need a jump?

No boost switch to jump truck from house batteries.
What would have been knocked loose to cause this?

That’s kind of impossible to tell you from here. It could be a myriad of things, from the spark plug wires to the wiring harness to a bad board on the ECU.

Not only do we not have the ability to look at your truck, but your truck is an RV, and RV’s are notorious for having bizarre modifications, both factory/dealer and user-installed, so we have literally no way of knowing how your truck is set up, and therefore next to no way of giving you specifics.

“Still did not answer the questions I posted.”

Well, whatever you paid to ask questions here, I would ask for my money back.

With the clarification and better understanding of what happened, I suspect the engine was flooded on the first attempts before and after the AAA guys tried. I also believe, now, that you didn’t need a battery, but just a charge. With the extra time to tow it to a shop may have been just enough time to let enough gas vaporize and escape to allow it to start.

And, I’ve had several occasions where a modern fuel-injected vehicle has flooded on me. Most after being parked for extended periods of time.