Bronco won't stay alive

[Nelson and Hudson]

@Uncle Gump No, I have not tested my fuel pressure. I need to make a reader that @BroncLander recommended. I'm still in the dark and need to find a good YouTube university video. I want to be safe about it.

 

[Uncle Gump]

Testing for proper fuel pressure should honestly be the first thing you check.

 

[Nelson and Hudson]

Testing for proper fuel pressure should honestly be the first thing you check.

I took it to the mechanic, and they called and said the issue didn't occur for them. Which is comical because it shut down twice just getting it around the corner for them. The B2 is a finicky b****. I asked about the fuel pressure and they said it was to spec. My curiosity is whether it's a faulty connection to the fuel pump causing intermittent failure. If they still cant find an issue ill take it on the freeway with a buddy and record it.

 

[Nelson and Hudson]

Update: They claimed they found and fixed the issue: The Ignition Switch. They swapped it out and it didn't die on the way home. So I'm going to take it on a test run later this week and see if it's truly fixed. Fingers crossed!

 

[RobbieD]

Seems to be a lot a lot ignition switch issues lately on the older trucks.

I guess that only rocks live forever.

 

[Cees Klumper]

Ignition switch is definitely a possible cause, I found out during my own oddysey with symptoms similar to yours. I replaced mine however the old one was fine, and in my case the cause of my intermittent stalling was (most likely) a vacuum leak under the intake manifold. Hope both of our Bronco II's are now ok, they are loads of fun to drive around.

 

[Terrys87]

There are several grounds on these trucks. https://www.therangerstation.com/fo...ation-as-i-find-it.204634/page-3#post-2004910

I really did not see your fuel pressure results. Both pumps good, fuel filter in great shape?

Ignition Control Module has caused me issues in the past. Eventually I want to mount mine from behind the distributor to a cooler area. There are some threads about that.

 

[Nelson and Hudson]

Good news / Bad News.

Good news: it doesn't die or struggle when coming to a stop or while driving.

Bad news: It is still doing this surging issue. After I bring up the B2 to speed around ~45mph it'll do this surging. I put my foot on the gas, and get an initial burst of a response, then it sputters out despite not moving my foot, and then a huge surge of power comes back, almost as if it realizes my foot hasn't moved and needs gas. When it starts to lose power, I'll press on the pedal and hear the engine roaring, but not a lot of power.

I need a Fuel Pressure gauge and a tach in the cabin so I can see what the values are when this is happening.

Is this a fuel issue or a transmission issue?

 

[Terrys87]

I feel it is still and engine issue. Where it is fuel or something else in the motor. My idling issue was the MAP sensor, but that is just guessing and throwing parts at it. How old are some of the sensors? I would be looking into sensors, vacuum leaks, plugged lines related to fuel and air flow myself.

 

[Nelson and Hudson]

I would be looking into sensors, vacuum leaks, plugged lines related to fuel and air flow myself.

I think you're right on the money. I don't have the best sense of smell, but when I was driving when the surging was happening my passenger thought they smelled "burning rubber" and gas fumes in the engine bay. I did not find any gas leaking, but a kink in the gas line is possible. I also fixed a vacuum leak from the EGR to the solenoid.
While driving at night I was cruising at 75mph for a while before the surging emerged. It happened when I had to slow down quickly. The surging can go away in time after keeping a consistent driving pace after punching the gas. Besides this issue, she runs great! I am really close to getting her running her best

 

[Nelson and Hudson]

Update: I drove 60 miles and not once did I have the surging issue. The only thing I changed was the Brake Booster pushrod. I never calibrated it so I figured why not check it out. Turns out, it was WILDLY off. It should be ~1" from the base of the brake booster to the tip of the rod. Mine was much farther than that, which might contribute to a few things: Dragging brakes, poor fuel economy, and a "vacuum leak". My theory is that if the rod is too long it creates a pressure difference, not suitable for the car, creating a "vacuum leak".

I created the brake booster measuring stick by 3d modeling it and 3d printing it, though you could use any tool that's roughly an inch. Attached is the excerpt from the Hanes manual and my stl that I created.

 

[richard booth]

I've had similar problem that ended up being a bad enertia switch, would die after driving a short ways, found there must have been a leak from the windshield that corroded the switch under the front carpet passenger side.