2002 XLT 4.6 wont start

[weedis]

i was driving in bad snow and when i pressed the brake kind of hard to try to knock a chunk of snow off the hood the abs kicked in and made the turck rumble and then stall. when i tryed to restart i got all the dash lights but no starter. also the milage now reads -------. also the fule pump is not turning on when i turn the key. i had a mechanic friend check it out with his big red hand held compter and he said it wouldnt talk with my computer and it must be a bad computer. so i went and got a computer from a junk yard and same problem. i then relized my 02 focus 2 years ago wouldnt start with all dash lights and ------- milage when someone tryd to steal it and cracked the plastic ring around the ignition. so i went and got a new column with key switched the ignition and plastic ring and still same problem.
PLEASE HELP.

 

[swetrid]

Ck the fuses, ford had a problem with dpfe sensors shorting out the 5 volt reference voltage. You can just unplug it and see if it starts.

 

[weedis]

Getting somewhere

so you gave me insentive to go back out to the garage and seek out the fuse for that sensor and it paid off. my mechanic friend had found a small row of fuses that were dead but not blown so he said. i checked those first and what do you know the first one a 30 amp fuse that is supposed to be a 15 was blown. in the under hood fuse box number 41 listed as 15A HEGO,VMV,CMS,PTEC. i have no idea what HEGO, VMV, CMS, PTEC is but i replaced it with a 15A fuse with that sensor unpuged and it started and ran for 1 min befor blowing the fuse again. i replaced it again and this time as soon as i turned the key to on not start it blew again.
so what is HEGO, VMV, CMS, PTEC? so i can track down the short.

 

[weedis]

oh and thank you for your reply wether that was it or not it got me pointed back in the right direction.

 

[matt0248]

HEGO is the Heated Oxygen Sensor. You probably have a shorter heater in one of the sensors or a wiring issue.

 

[weedis]

have 4 o2 sensors. i found that one of them had the wires touching the pipe and had burned thru. i fixed that and still replaced the fuse to have it blow as soon as i turned the key to on. could one of the sensors be bad and blow that fuse? because i cant find any more broken wires. acording to my haynes book those dont even turn on till the engine is warm. also 2 years ago i remember puting that 30A fuse in there. at the time i didnt have the book so i i just replaced the 30A because thats what was already in there. can i get 2 more years with another 30A.

 

[matt0248]

They o2 sensors have heaters to heat the sensor to get it to work faster after a cold start up. They may not shut off at all. Unplug all the sensors to see if the fuse blows. PLug them back in one at a time to see when it blows. Or, get your wiring diagram and multi-meter. Unplug the PCM connectors and measur the resistance of all the wires to each sensor to see if one is shorted to ground.

 

[ScubaDave]

Fact is stranger than fiction!

I had just finished a rather long replacement of my rear wheel bearings on my '02 EB Explorer and took it out for a test drive. When I got back, thankfully, I stopped it and then tried to restart it. It was dead to the world!!

Everything worked fine, but it just wouldn't engage the starter circuitry at all. I had a similar problem before and it was associated with the 4x4 control module, I thought. At least it was blowing fuses and didn't start then because of that. But, I have removed the CM entirely for now and so it had to be different.

Checking fuses, though, was my first step in troubleshooting this problem, too. Found that Fuse 41 for the HEGO PTEC, VMS etc. was blown. Good material on tis site to shoot this problem. The same reason as mentioned here was the cause of the fuse popping, but the cause of the short was a bit different. All my wiring was well away from the exhaust sytem and showed nnow signs of melting due to heat.

Instead, my wiring for the foreward O2 sensor on the left side was that the sheath was laying on the front drive shaft for the 4x4 drive. It had worn through the sheathing and the wirre insulation on two ofhte four leads in there. Luckily, it was fairly accessable and quickly repaired. In addition, I used a zip tie to hold the bundle from the O2 sensor up off the shaft to avoid a repeat in the future.

Without the suggestions here in this forum, though, I would have been lost. Thanks to all the members who have added their two cents to the site and made it a very valuable tool for us occassional mechanics.

Now, to go after that 4x4 Control Module!

ScubaDave