1986 Bronco II starts and dies

[duncan666]

I have an 86 Bronco II with 2.9 v6. Engine starts but dies in 8 seconds. Then no start. If I wait 4 hours it will start again for another 8 seconds.

 

[SunSpot]

My first guess would be fuel problem.. a stopped up filter or bad/weak fuel pump. 8 seconds huh? that is just about how long it would take to burn the fuel in the injector rail. you try leaving the ignition on for like 10 minutes letting the fuel pump try to get more fuel in the rail before starting it again?

Sounds like a filter the more i think about it. if it happened suddenly, then maybe the fuel pump. Just my guess tho

 

[andre]

first is it fuel or spark

take plug as tester grown it somewhere see if u have spark

put key on can u hear fuel pump noise huuuming sound from the tank

sound like fuel prob those test send u in rigth directoin

need more help let us know

GL

 

[duncan666]

My first guess would be fuel problem.. a stopped up filter or bad/weak fuel pump. 8 seconds huh? that is just about how long it would take to burn the fuel in the injector rail. you try leaving the ignition on for like 10 minutes letting the fuel pump try to get more fuel in the rail before starting it again?
Sounds like a filter the more i think about it. if it happened suddenly, then maybe the fuel pump. Just my guess tho

There is 40psi pressure at the fuel rail.

 

[duncan666]

first is it fuel or sparktake plug as tester grown it somewhere see if u have spark

put key on can u hear fuel pump noise huuuming sound from the tank

sound like fuel prob those test send u in rigth directoin

need more help let us know

GL

Engine has spark and fuel pressure at the fuel rail. I suspect the injectors are not firing. how do I check for this?

 

[SunSpot]

Some Sensor (failures) that control injectors:

There is a Temp sensor next to the waterneck (left side as you face the engine) which works sort of like a choke. when engine warms up it adjusts fuel mix. It is brass with a 3/4" round plastic connector and a couple of wires going into it. I dont think 8 seconds would be enough to make it function, but possibly.

temp sensor

The air charge sensor in the intake manifold, in the center runner on passenger side of intake. That also adjusts fuel mix depending on flow.

air charge sensor

The MAP sensor located on firewall above the evaporator case (passenger side). It's black has a vacuum line and a 3 wire connector going to it.

MAP sensor

Trial and error here might be expensive. This is assuming you have fuel pressure and spark after it stops running (in 8 seconds) Maybe you could get all these parts for 10 bucks at salvage and see if it makes a difference. dunno.

 

[hobbybob]

accident please delete post!

Thanks!