Hi! We have a 1991 Ford F250 Diesel Truck. Recently we accidentally put gas instead of diesel in one of the tanks. We drove only a few minutes and shut it off, and then it wouldn't start. So we switched to the other tank, drained the fuel line that goes from the pump to the filter, took the filter off and poured out the gas and filled the filter with diesel, bled the air out, and got it started. After that, we drove around and it seemed to be running fine. It did begin gradually to get harder to start, it would have to crank longer than usual, but then it eventually would start up and run just fine. Then we took it on a longer trip. On the way we had a flat tire. As we were changing the tire, we noticed a significant leak in our radiator. We filled it up with water, and continued on our way. At the top of the hill, we filled the radiator again, also adding some pepper to it, as someone told us that might help stop the leak in the radiator. When we got to town, we bought some regular radiator stop-leak formula, and put that in, topping it off with more water. The gauge never showed that the engine overheated. We got some diesel, and made a few other stops. It always started up again, but now it won't start. It sounded like the batteries were losing power, so we tried to jump-start it. We bought a new fuel filter and installed it. But it still didn't start, so we took the batteries out and had them charged at Wal-mart and Les-schwab. One of the batteries was bad, so we got it replaced for free (they are interstate batteries and they were still under warranty) The man at the interstate store told us that the batteries were new enough (20 months old) that they wouldn't have to replace both batteries, because one was still good. So we recharged, and then reinstalled the batteries, and tried to start it, but it still doesn't crank fast enough to fire. We even tried jumper-cables again, with the new battery and the other battery charged, but it still won't start. So now we are charging the batteries again and wondering what we should try next?

Using a hydrometer, ensure that you do not have one or more bad cells. Do this after you have fully charged each battery.

Stop jumping the battery, unless you want to fry your PCM, alternator, and sensors. All it takes is a voltage spike or hooking up the cables wrong for a fraction of a second.

Also, clean the battery terminals, cable connections, and main ground. Check the cables for corrosion and/or hidden breaks. Clean the connections going to the starter motor.