The car stalled, now I need to figure out what happened (Page 1/1)
BlackEmrald DEC 02, 01:26 AM
The car is a 1996 Ford Thunderbird Sport, 4.6L V8/auto.

This has happened twice and stalled once. I am driving the car, slowing down for a light. The car makes a "hum" sound, somewhat distant. Once I have completely stopped, the hum will stop, the car will lurch, and the RPM's will drop. It stalled once. No issues starting it back up afterwards. A few days between instances, but I haven't driven it since.

All fluids are full, recent oil change. No unsusal noises under the hood while idling or revving.

I am not sure if this is related, but when the car is idling, sometimes the voltage drops and the lights go dim. Almost exactly like when you have a huge amp and you sub hits real hard.

Also unrelated, the AC compressor constantly cycles on and off while the ac is on. Maybe a problem with the pressure switch?

Thanks all

[This message has been edited by BlackEmrald (edited 12-02-2012).]

carnut122 DEC 02, 10:24 AM
My 95 Mustang GT did the same type of thing and I didn't figure it out until it finally died completely. Mine was a 5.0 V8 (yes, I know it's a completely different engine). It turned out to be the pick-up coil in the bottom of the distributor. I suspect yours gets the same info from either a cam sensor or crank sensor. Have you checked for computer codes? As for the AC, the most likely suspect is that it's low on refrigerant.

[This message has been edited by carnut122 (edited 12-02-2012).]

BlackEmrald DEC 02, 10:58 AM
I haven't checked for codes, there is no engine light. I know that doesn't mean no codes though. So do you this the voltage drop is related? Also what could be making the humming?

Thanks for the input!
carnut122 DEC 02, 09:35 PM
Does it act like you're driving a manual transmission car and forgot to push in the clutch before it dies? If so, maybe the TCC solenoid isn't unlocking? Does it have an AOD tranny in it? I have a 5.0 SBF in my current project and the IAC valve makes quite a loud humming/vibrating type of noise. I'm not sure about the voltage drop except maybe it a result of the RPM drop?? I'd get the codes read first. Maybe at AZ if you don't have a reader.

[This message has been edited by carnut122 (edited 12-02-2012).]

Khw DEC 03, 12:36 AM
Along with that pick-up coil it could be the cam sensor or crank sensor. Not a Thunderbird, but our Bonneville would stall out from time to time and at first it started right back up. As it progressed, it would take a few minutes before it would start back up. It ended up being the crank sensor. We also had another problem where it started to bog down and would stall out, which ended up being the MAF sensor. When that happened, you could floor the accelerator and keep the engine chugging, but you'd have next to no power, just enough to pull over and maybe make it into a parking spot. When I unplugged the MAF, it would run fine, although the check engine light was on and our gas mileage decreased a little. Once I replaced the MAF it went back to normal.

[This message has been edited by Khw (edited 12-03-2012).]

mwzephyr DEC 07, 04:12 PM
Just rebuilt my brother's 94 ford thunderbird lx 4.6l engine with ac
The ac compressor if the ac is on will cycle very often on high and mediuum only if it is very hot out.
The stalling thing. Idle is affected by several things. Check for vacuum leaks first.
Doesn't sound like injectors or the pcm either. Because it is intemittant leads me to suspect that when the engine gets hot
the vacuum leak ~cracked hose likely softens up and starts sucking air that often makes the car run lean because if the oxygen sensors get a wiff the car tries to cpompensate and the car will choke out.
Also if your exhaust pipe has wornout gaskets at the flanges that will cause the problem too.
There is a rubber t fitting at the back of the engine on the pass side where vaccum hoses lead into it most often get hard and cracks.
Doorman makes a replacement for several dollars and it might just solve your problem.
Right now the problem is intermittant if it were a regular thing then we'd be looking at fuel delivery and clogged or bad injectors I think.
Also it wouldn't be a bad idea to remove the air snorkle and spray some egr safe crb cleaner intop the butterfly valve if it is getting gummed up . Caution don't start putting injector cleaner into your tank, that is the least of your probems and will only mask the real problem.
also a bad gasket at the intake/ butterfluy could be leaking.
I think you would have replaced your pvc valve and done a visual check.
Please report back with what you discovered.
Unplugging your maf puts the computer into limp mode so you can run your car to get it home...it also causes the check engine light to come on.
you have two ignition coil packs most likely ~if you had a secondary ground intermittantly because of a cracked coil you would have stumbling or missing when it was damp or wet out. I don't think that is your problem.
Thanks
~Zep

Had pontiacs and oldsmobiles and cadillacs too.
I have had Fords and lincolns most of my life and have a 99 taurus now 3.0 v-6 vulcan / pushrod engine
You have a pm/ see your mail

[This message has been edited by mwzephyr (edited 12-07-2012).]

Kekipi DEC 08, 02:49 AM
Follow the PCV hose to behind the engine. They get soft and act like yours. You can't see it, just feel for it.
BlackEmrald DEC 08, 03:54 PM
I will continue to check for vacuum leaks, but what would explain the humming sound? Also, I have no CEL.
carnut122 DEC 08, 11:12 PM

quote
Originally posted by BlackEmrald:

I will continue to check for vacuum leaks, but what would explain the humming sound? Also, I have no CEL.



I'd still check for stored codes. Could the hum be the radiator fan?
BlackEmrald DEC 09, 02:25 AM
I doubt it. It was very pronounced, as I could hear it over the radio and road noise. I also thought it may be something belt-driven seizing up, but in my experience it usually breaks the belt when that happens. I see no signs of belt wear or wear on any pulleys. I'm stumped. I am going to go get some Vacuum line on Monday, and I will have them read the codes while I am there.