Expedition Wont Start Unless Jumped - New Battery
 

I’m a former GM Tech, and I need help! My wife has a 2004 Eddie Bauer Expedition with the 5.4L, 4x4, every option, 140,000 miles. We’ve had the car for about 2 years. Everything was fine until one day, it developed a dead miss. I pulled the codes and had a Cylinder 5 misfire. Replaced the coil, no change. Replaced the injector, then it would crank, but wouldn’t start! So I put the old coil and injector back in #5, and it still won’t start! Tried until the battery started to sound weak, with no luck. So I put a battery charger on it, and it fired right up! Drove it down the road and it drove fine all the way to town and running errands (I left it running when I went into the store). Drove for about 30 mins with no problem. On my way home, I was driving down the road and the security light on the dash started flashing and the engine lost power and started misfiring like crazy. Pulled to the side of the road and the engine honestly sounded like a diesel, as the security light on the dash kept coming on and going off in no particular pattern. Then, all of a sudden, the security light goes off and the engine returned to a normal idle. Got back to the shop and shut the car off. Now, it will turn over, but won’t start, and as it’s turning over, the starter relay in the passenger floorboard fuse box clicks on and off rapidly the entire time the engine is turning over. When you’re under the hood as somebody tries to crank it, there almost sounds like there is a rotational “click”, like something is shorting in the alternator every time it passes a certain point in its rotation. I pulled the belt and tried to start it with the alternator wires connected, AND again with them disconnected, but nothing changed. Also, sometimes the starter will turn for a second, then stop turning over, even though I haven’t released the key from the start position. No matter what, it will not start UNLESS I hook a battery charger to the vehicle and set it to 12v - 125Amp start, then the vehicle will turn over and start on the first try. The battery measures 12.4V at the posts with a meter, and I have installed a new battery, but nothing changes. I am getting 12.2V at the fuse box in the passenger floorboard. I’ve tested the grounds at the PCM, the main ground on the battery, and the engine block grounds as per ALLDATA, but all were in spec. I replaced the PCM and paid a guy to come to my house and program it. The part number for the new PCM I received was different than the part number for the one that’s on it, but I called the local Ford dealership and they said it should work, but who knows. Either way, it didn’t fix anything. Here’s what all I have replaced:



Battery

PCM

Starter

#5 Fuel Injector

#5 Coil



When I drive it down the road, it runs normal for a while, then the security on the dashboard will come and the transmission will drop into neutral, the engine revs up, then it shifts into gear, shifts into OD, and runs normal again until the next time the security light comes on. Please help! I have a video of it doing that driving down the road. Anyways, I'm not sure where to go from here! Thanks in advance for any help, this one is making my brain hurt lol

The video of it acting up driving home was too long to upload here, but here's a link to it on YouTube. Watch in the center of the dash when the security light comes on, then the RPM's shoot up.

Hi Al,
Welcome to the club, we have all been there at one time or another and speaking for myself been there many times. It comes with the territory LOL
Computer circuits as you already know are very voltage sensitive and if there is a big enough voltage drop, they just shut down. That leads me to my next question have you had a chance to do any voltage drop testing of the battery cables and their connections ? Because it seems to start without any problem when jumped ( addl power now available from battery or charger etc>) there may just be a poor connection or hi resistance either in the cables ,the connections, or power coming into the vehicle.
I know you you know all this, but sometimes we forget, what do you think?

Hank,

Thanks so much for the quick response, I really appreciate it! I've thought the whole time that it was a voltage issue or bad ground based on how it acts when I try to start it, I just couldn't understand why it would be doing it driving down the road when the voltage output SHOULD be fairly stable. I will do a voltage drop test on the starter circuit and to the main power distribution block, as well as check the battery cables, as soon as I get home from work. Thank you again for the quick response. I'll check back in with my results.