Bronco II dies/stalls while idle, coming to a stop

[Nelson and Hudson]

Hello, I've been trying to track down this problem for ages so hopefully someone can offer some advice. (1987 Ford Bronco II, 2.9L V6)

When driving around at low speeds, the engine will just randomly shutoff with no warning and then flash the "emiss" light. I can catch it if I'm quick enough by turning the key, which will give it a boost of power and it'll continue to run for a while. Doesn't matter if it's cold or hot. After driving around for a while and pulling into a parking spot, the engine will die. Doesn't happen on freeway speed and it runs and idles really well.

I replaced: Fuel filter, oil filter, new oil, alternator, starter relay to starter cable, ignition coil + connector, distributor and cap, wires, ignition switch, plugs gapped, new battery, cleaned the IAC

 

[franklin2]

Take the throttle body apart and clean it as well as the idle air bypass valve.

 

[ThatOneGuy]

Take the throttle body apart and clean it as well and the idle air bypass valve.

This I have a mazda b2300 does almost the same thing when coming to a stop. Unless I bleep the gas before a full stop. In my case I've gone under the hood and watched the throttlebody/tps not function smoothly.

 

[Nelson and Hudson]

clean it as well and the idle air bypass valve.

I actually did clean the IAC a few months ago when trying to fix this issue. I'd rather not have to take apart the upper intake manifold just to clean the throttle body though.

 

[Nelson and Hudson]

I would also like to note that it consistently stalls (dies if I don't catch it) when I see the temperature gauge reach operating temperature. Why would this be?

 

[rusty ol ranger]

I would also like to note that it consistently stalls (dies if I don't catch it) when I see the temperature gauge reach operating temperature. Why would this be?

Get yourself a EEC IV code reader and pull the codes.

Does it show signs of flooding or fuel starvation? (Smoking black, low idle, puttering to a stall)

Also pulling the throttle body doesnt require removal of the upper intake...its only 4 bolts on the front of the intake that hold the TB on

 

[franklin2]

I would also like to note that it consistently stalls (dies if I don't catch it) when I see the temperature gauge reach operating temperature. Why would this be?

Because the computer is running the idle speed higher because the engine is not fully warmed up yet. When the engine fully warms up, it goes into normal run strategy and reverts to the normal idle speed. The normal idle speed is achieved from air from the idle control valve AND the little bit of air that goes by the throttle blades. If the throttle blades are gummed up with sticky carbon, it changes the amount of air flowing by the throttle blades.

 

[gaz]

@Nelson and Hudson ,
Since you have an automatic transmission, your torque converter could be failing. The only time I've ever seen an engine die with an automatic transmission, it was the torque converter or the tranny failing

 

[Nelson and Hudson]

@Nelson and Hudson ,
Since you have an automatic transmission, your torque converter could be failing. The only time I've ever seen an engine die with an automatic transmission, it was the torque converter or the tranny failing

Shoot, any way to test to confirm it's one or the other?

 

[franklin2]

Shoot, any way to test to confirm it's one or the other?

You can tell when that happens. The engine pulls against the brake as you apply it. You have to put more pressure that usual on the brake pedal till you kill the engine with the brake. I think you would notice this.

 

[gaz]

Shoot, any way to test to confirm it's one or the other?

@Nelson and Hudson ,

The first time my 87 BII stalled, I checked both the ignition and fuel systems. My in tank low pressure fuel pump had failed.

After replacing the failed low pressure fuel pump, several short months later, with a good fuel and ignition system, it was the torque converter.

I removed and replaced the torque converter, while out, I had the transmission looked at. The shop pointed out that it had some life left in it but would perform much better, much longer with updated rebuilt components. I did the prudent move and swapped 87 A4LD (approximately 140k miles) as a core for a fresh, updated rebuilt version of the A4LD in 2008(ish). The failed torque converter was causing the engine to stall, first while driving, then in the end even shortly after start up.