Please just go to the last reply ******* Help!!!! 97 f150 4x4 xlt 4.6l about 200kmiles on it
Battery died, after 7 years. I guess It gave me a good run. Went out and got a new Battery same exact one. Old battery had been out 2 hours. Put new one in, went to start, got a very loud Bang or POP ( heard down the street ) First thought cause of symptom but not what had I had changed, can a Crankshaft position sensor blow up and make a noise like this
almost like a loud backfire from engine area. Smoke ( gray ) coming from what looked like under the manifold riser, or back of Alternator. Once smoke cleared, duh I tried to restart. It started fine, then died instantly. If I start and mash the gas, it runs for a moment then dies. Started troubleshooting, and found that without the key in the ignition and everything else in the engine cool the alternator is still fairly warm. also when I touch the battery cable to the battery get a click from the module right behind the fuse box, like a relay or something closing. Dont know if significant

Not dumb when it comes to engines basic understanding, but I cant figure out what happened. Hooked up odb2, no dtc's found ( probably cleared when I had the battery out ) it has had a low egr code for a while, I just hadnt taken apart the trottle body to clear the carbon buildup cones from inside it yet ( had to do that years ago )

man, ruined the whole weekend - was suppose to be fishin, and have vacation next week. suppose to fish then too. not a whole lot of $, so I have to figure this out myself, HELP!!!!!

 

Not trying to be funny but are you positive the cables are on the correct battery posts. I'm not even sure the truck would do what its doing if they were hooked up wrong but just a simple thought.

 

if it turns out to be altnator, i took mine to shop and swapped for identical one they already had rebuilt and saved between 40 and 50 bucks. listed under armature and generator repair. good luck, and not hard to change out, just a little tight space.

 

Heheh yeah, I got the right cables, on the correct battery posts, thats the first thing I checked, just in case I pulled a bone head, Yeah, Ive changed out the alt, Pain in the ---. but the altatnator would cause this systom of starting then instantly ding would it

 

Have you checked the alts inline fuse / follow the Orange then Yellow line up by the firewall. It's a mini 20amp. Also,- check you MEGA fuses (175's) . What the hell burnt, popped and smoked is what I would want to know lol.

 

My top priority would be to find the source of the pop & smoke.

 

1st thanks for the replies
none of the fuses and mega fuses look like they are popped.


Yes, that is what Im trying to find. Cause I figure if I found what popped and smoked, it would lead me in the direction of is going on. The smoke once I opened the hood back up, was coming from the space inside the riser manifold, with is also around the back of the alternator. But I dont see anything offhand that looks like it burnt. These 4.6's with there hollow areas inside the engine YOU cant or get to without taking the whole top off. the problem is thats where it looked like the smoke was coming form.

#1 does anybody know if the crankshaft position sensor could make a sound like that?
#2 what else is down in that area that could make a pop and smoke like that
#3 another sympt - The fuse or relay in the small fusebox on the fire wall, the fuse for I think is the ecm clicks when I otuch the pattery cable to post, Now, I dont take of my cables everyday but is that it just getting power or an indicator of an issue.

Appreciate any ideas, cant find anything that looks burnt, I'm at a loss Could an Alternator make a sound like that, never heard of anything like it.

All from changing out a battery, go to do it myself cause dont have $$$ to put in the shop.

Help and many thanks beforehand

 

Not bagging. Did you maybe leave a tool laying in there (bang) and have it hit/rip something loose (smoke) ? Just a thought, count your wrenches.

 

Thanks, But no tools, The only tool I had was One small wrench and a terminal puller/cleaner for the battery. Still have them, no the bang was very similar to a back fire, thought it was at first until I saw the smoke coming for undernieth the hood even then I thought It might have been a backfire thru the intake and thottle body. but if it had been that the smoke should have come out my airforce1 tube and filter.

thanks again, still out here looking in futility

 

I'd take the alternator in to one of the parts houses and get it check it sounds like it has shorted out. had one on an old datson that i was working on do a simular thing it was a loud pop kinda like a transformer blowing or a large fire cracker but i'd start there.
Hope this helps
Stephen

 

If the CPS had exploded, the engine wouldn't even try to fire; much less run, even for a couple of seconds. Have someone start it while you listen under the hood for hissing (vacuum leaks) or other abnormal noises.

Many modern engines have exposed valleys, and Ford modulars are among the easier to access. And a closed valley wouldn't be any easier to get at. But I doubt your problem is under the intake, anyway.

 

When it did start for a few did you hear any noises? Any chance there was a hydrolock on startup? Have you pulled the sparkplugs and checked for damage? A broken rod can punch through the block in the valley or side of the block letting smoke out. Not sure what would cause smoke under the intake unless you had a fire in the intake and it blew a hole through the bottom of the lower intake. There is a knock sensor under there but can't see that being a source of smoke unless the wire burned. Maybe the egr tube is broken and the smoke from a backfire blew through that crack and up around the intake? Those tubes are almost always broken right at the exhaust manifold on trucks of your vintage. Still doesn't explain why it won't crank/start.

 

Nope, no Hydralock, pulled 4 of the 8 plugs they're all fine.
This is went down as far as noises.
#1 replaced the battery ( done tons )
#2 jumped in turned key about 2 seconds later, BANG!!!!
#3 turned key off - and noticed smoke coming from under hood
#4 jumped out and opened the hood slowly ( didnt know if there was a fire)
#5 most of the smoke left looked like it was coming from under the manifold riser around the back of the ALT
#6 after a moment, for kicks tried to restart, Cranks and goes to start fine, then dies 5 secs later. I did mash the gas down once and it stayed on a couple of secs longer

Trying to put it in a way that will put a light over someones head,

Will be taking the ALT out tomorrow to go get it bench tested. Would the resistor on the battery pop like capacitor like that, and would a dead or over charging alt make the truck act that way with a new battery, my volt meter battery corroded the contacts(should have left the battery in it, so im out there too, would of had the alt out by now, but in the tight space cant figure the belt tensioner, most have a bolt on them, or a slot for a 4 inch drive, this one has a round hole, any tricks there????

 

use a 1/2" drive ratchet for the belt tensioner. Right after you get the belt off, spin the alternator by hand and wiggle the pulley to see if there is any play.

after the belt is off and before you unhook it try to start the vehicle with the belt off and see if it will run.

 

good advice, i would start here as well