i have a 94 f-150 with a 4.9l inline 6 cylinder, automatic overdrive transmission.ever since ive had the truck, its had an issue with the engine starting to bog out and eventually dies. when first starting the truck, a beeping sound starts in cycles of 4 beeps, then 5 beeps 4 times. any ideas what that means? anyhow, when the beeping stops, the bogging out and dying starts, like its misfiring and the engine light comes on. no codes, and can start right back up. brand new ecm in it as well. any input is welcome!

 

Where is this " beeping " coming from ? The dash , under hood ? Did it have some kind of aftermarket security system installed that is wigging out ? Strange .

 

Yeah, the beeping is definitely not stock.

Welcome to the forum.

 

First thing(s) that comes to mind:

Clockspring in the steering column
Poor grounds/battery cable(s)

My truck beeped before and after I replaced the clockspring mechanism.
It was said to me, "That's definately your problem".
It wasn't.

I'd start by cleaning off all of your ground(s) and ground points untill they're shiny and bright, then see what happens. That means ALL of your grounds....not just the easy ones you can see.
I haven't had a beep since then.
Oh, I think that beep is the door or seatbelt chime "trying" to ground itself.

Bob

 

Tone Generator

The air bag indicator is the prime means of determining the supplemental air bag restraint system status. However, if the air bag indicator is inoperative and a system fault exists, a tone will sound in a pattern of five sets of five beeps. If this occurs, the air bag indicator will need to be serviced before further diagnosing and testing can be completed. Unless serviced, the supplemental air bag restraint system may not function properly in the event of an accident.

 

well, ive read a lot of forums this evening and just about all of them say the beeping is from the air bag system, and i went to check the dash when turning the key to the on and run position, and no airbag light comes on, so that makes sense. but the stalling and choking out is really got me stumped. no security systems or anything insstalled. bone stock truck.

 

If the engine light comes on you have a code set in CM. If CM comes back with a 111 when checked then I think you need to take that PCM Computer back and get another one.
Make sure you are looking for CM codes after the KOEO test is over and you get the 10 code (separator code) then the CM codes will start.

 

i dont think it has anything to do with the ecm honestly. it did this exact same thing with the old computer. im thinkin its more on the ignition side of things. too late and cold to go outside and mess with it tonight. curious if anyone else has experienced the same symptoms. but there is not an engine light with the truck running. know how it comes on when you turn the ignition to on/run position with the engine off? thats the only time it comes on, and when it stalls out. so there arent actually codes being stored, ive already read them out again

 

Ck ECM grounds and powers for loose connections . The CEL lamp will come on and no codes ? I would ck grounds first . May just be a bad connection .

 

nah, the CEL only comes on when the engine dies. thats normal as far as i know, happened with every other f series ive owned. im gonna stick a timing light on it tomorrow and see if i can find some kind of jacked up wire or somethin

 

Sounds like then your fuel pressure is dropping too low to keep the engine running.
Maybe you have a plugged fuel filter, junk inside the fuel tanks or a bad fuel pump.
Do you have two tanks?

 

yep, got 2 tanks, but i dont think the back one works. does that really sound plausible though? its strange to me that it can drive for 20 minutes and all of a sudden start doin this weirdness

 

If it was the PIP sensor or the ignition system in general you would get a code.
It sounds to me that you have bad fuel pump or the electrical power to it.

 

hm..ill check that and see what im gettin. thanks for the help, ill update whats been found and fixed. youd think this would be a walk in the park for me, im an electronics tech on helicopters.

 

Just out of curiosity .............

When your truck is running, pre stalling, have you felt/touched the braided ground wire that goes from the firewall to the intake plenum to see if it's warm or hot to the touch ????

And, try touching the area around the ground at the fender, near the battery, where the 10 guage wire is, and see if that's warm or hot.

All of this sounds like a poor/resistive ground somewhere.

Bob