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Bronco Dying Lately

1strodeo

Squirrel Watcher
Joined
Sep 15, 2016
Messages
3,596
Loc.
Wisconsin
Hello All, my Bronco has been running great for months now, but on my way home the other day I'm cruising about 35-40 and it starts sputtering, I feather the gas pedal enough to get it off the road. Shut it off for a couple minutes, crank it back up and drive home (about 10 mins).

Yesterday I go to the junkyard, about a 20 min drive no issues. I'm probably at the yard 20 mins or so then I get in to leave and let it idle for a few minutes (as I'm posting to a thread %)) and it dies. The clear inline filter has a little fuel in it but not much, so I remove it and blow it out. NOTE When i remove it the 1/2 oz of fuel that pours out of the carb is boiling on the manifold. Reinstall filter and now will only run for one second, but plenty of fuel in filter now.

I get it to run well enough to hit the road and I make it maybe 10 miles, at a stoplight starts to die again, and again I feather the pedal to a safe place off the road. I let it cool down a little and this time I remove and blow out the screw-in filter at the carb inlet, get it running again. Again go about 10 miles, 2nd or 3rd stoplight it dies...I eventually make it home.

I have a '69 302, mechanical pump and an '85 Holley 4150/4160 with auto choke. My entire fuel line from carb to tank is wrapped in exhaust heat wrap. Fuel tank is pretty level, however I've ALWAYS had to fill it very slowly at the gas station?? It used to only hold about 8 gallons until i discovered the tank was quite unlevel.

Been looking for a reason to get a new carb with manual choke, but this one has always run so smooth! Any ideas appreciated. Here's an older pic of my setup, before I wrapped the fuel line.
 

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B RON CO

Contributor
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Messages
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Hi Jeff, it sounds like you are running out of gas.
Did you check all the filters?
If your carb has a fuel level screw you can remove it and the fuel should weep out.
You can see how fast the fuel line at the carb fills a coffee can. It should fill in 15 or 20 seconds while cranking at the solenoid or remove the coil wire and have a helper crank the key.
Good luck
 

gick70

Sr. Member
Joined
Jan 30, 2011
Messages
544
I had a fuel pump go out slowly this year,sounds the same,3 years old,China junk.I cut it open and the billow was all cracked up!I had to tach it up real hi just to keep it running!
 
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1strodeo

1strodeo

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Joined
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Messages
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If your carb has a fuel level screw you can remove it and the fuel should weep out.

Thats exactly what I did when i got home from work Ron, front bowl was way too low, rear bowl was too high, got them both dialed in and went for a good long drive...accelerates well, as it always has, but low acceleration is much like driving with fouled plugs (which they may well be, NOW) and idles very low...would adjusting the bowl levels affect the idle? Guessing I'll need to tune the carb tomorrow, as every change necessitates more changes.

I had a fuel pump go out slowly this year,sounds the same,3 years old,China junk.I cut it open and the billow was all cracked up!I had to tach it up real hi just to keep it running!

Let's hope it's not the pump, but ya never know...would it run ok and die at idle due to a bad pump? No idea about the pump, came with the Bronco, but definitely not original! thanks guys
 

B RON CO

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Hey, I don't know what low acceleration means, but you can try advancing the timing. That often wakes up a sluggish engine.
Then go over the carb. Get the fuel to just weep out of the front bowl. The rear bowl can be set a hair on the low side. Then tweak the idle screw and then the mixture screws on each side of the front bowl. Do this at least twice.
Is your vacuum advance on the ported ( high passenger side Port) or direct manifold vacuum? I like ported vacuum. If you have a timing light you can watch the timing mark move up under the water pump as you give it gas.
Good luck
 
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1strodeo

1strodeo

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Messages
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Hey, I don't know what low acceleration means, but you can try advancing the timing. That often wakes up a sluggish engine.
Is your vacuum advance on the ported ( high passenger side Port) or direct manifold vacuum? I like ported vacuum. If you have a timing light you can watch the timing mark move up under the water pump as you give it gas.
Good luck

I don't know Ron, it's got one of those funky GM distributors. Don't think they have vacuum advance? The 'low acceleration' just meant light pedal...half pedal or more runs fine but light pedal tends to sputter a bit.

Maybe trash/sediment in the gas tank.

Very well could be, perhaps even enough to cover the vent?
 

El Kabong

Contributor
Driving stuff Henry built
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Messages
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You might also try popping the gas cap next time it comes up. Normally proper venting will allow air into the tank as fuel is pumped out. If there is a vent problem the tank can build vacuum to the point where fuel won't pump out. If you hear a rush of air when you pull the cap then look for a vent issue.
 

SHX669

Bronco Guru
Joined
Jan 9, 2009
Messages
1,997
Fuel pumps are relatively cheap and easy to replace ---
I had a fuel delivery issue that turned out to be a deteriorated "sock /filter " on the pickup tube . It was in small pieces and plugging the fuel pickup .
 
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1strodeo

1strodeo

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You might also try popping the gas cap next time it comes up. Normally proper venting will allow air into the tank as fuel is pumped out. If there is a vent problem the tank can build vacuum to the point where fuel won't pump out. If you hear a rush of air when you pull the cap then look for a vent issue.

Think I read that in BGBronco's thread too, will definitely try that

Fuel pumps are relatively cheap and easy to replace ---
.

I've wasted enough money in my life replacing parts that didn't need to be, now I prefer to troubleshoot, much more rewarding...and of course cheaper ;D

By the time i had adjusted both bowls yesterday, the clear filter was full of fuel, so I don't think the pump is bad. I'm hoping that fine tuning the carb this evening will resolve my issue...however the tank always being difficult to fill makes me wonder if I have issues at both ends of the fuel circuit.
 

Attac

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Messages
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Jeff
That HEI distrib has vac advance. Thats the rubber vac hose on the front diaphram. I think you are gonna find that it's prob an adjustment issue in the carb.
It is easy enough to pop the fuel line off and see how much volume you get out of it to rule out the pump though.
Chuck
 

B RON CO

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Hi, and the first picture shows the vacuum advance on the distributor. Post a picture where the rubber hose goes on the carb or manifold. Do you have a timing light?
Good luck
 
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1strodeo

1strodeo

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Thanks Chuck & Ron, I guess I could have answered my own question by looking at my own pic %) So the vacuum line goes from the distributor to the front of the throttle plate, and yes I have a timing light...however....

I tried to advance the timing at 3500 RPM - according to the book I used to build my Mustang 302 - but I believe the distributor rotation is being limited by the fitting in the manifold that goes to the heater core. By this point it was dark, raining and I had to make dinner, so that's where I'm at, thanks again all.
 

B RON CO

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Hey, so the base of the distributor is hitting a fitting on the manifold, limiting the adjustment. Usually the vacuum cannister hits something.
Post the ignition timing at idle, with the vacuum hose disconnected and plugged.
The book says 6* BTDC, but you can shoot for @10* or more, as long as it doesn't ping.
Good luck
 
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1strodeo

1strodeo

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Here's a better angle of what I mean in this much more recent pic...the vacuum canister has plenty of room, it's actually the distributor cap itself that's hitting when turned clockwise.

So I either need to find a new fitting or put a FORD distributor in ;D

Also the balancer has so much paint on it I'm having trouble reading the degree marks %)
 

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El Kabong

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Here's a better angle of what I mean in this much more recent pic...the vacuum canister has plenty of room, it's actually the distributor cap itself that's hitting when turned clockwise.

So I either need to find a new fitting or put a FORD distributor in ;D

Also the balancer has so much paint on it I'm having trouble reading the degree marks %)



Can you move the spark plug wires around 1 position on the dizzy cap? That seems like it would allow it to be rotated to where there is no interference.
 

B RON CO

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Hi, the holdown screw is preventing to from giving it more advance.
You can remove the cap, turn the distributor and put the cap back on.
If that was my cap I would have no issue with filing that screw off. The other 3 screws will hold the cap.
Clean up the timing mark and know where you are starting from. The engine run better with a little more advance as long as there is no pinging.
Good luck
 
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1strodeo

1strodeo

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So I got another clue this evening...

I've messed with the timing several times but it ended up back where I had it when I set it several months ago, so I've been focusing on the carb. Found out it's actually a Holley 4180 that was on a truck either with a 351 or 460. The article I found about this carb was specific to Mustang GT 5.0 (83-85) and sounds like it was an emissions-focused carb that preceded fuel injection and produced 175 HP - which was significant vs the 82 Mustang 5.0 - and thus, the air-fuel mix cannot be adjusted...at least not easily.

Anyway now it's idling very high and there's not a whole lot i can do about it, other than move the distributor. I tried to retard the timing a bit yesterday for this reason but then it didn't want to start. So again, back to original timing setting. Today I go for a drive, good 20 mins, several stop lights, idling high at every stop, I get home and throw it in reverse, and idle drops significantly. I pop the hood and the clear fuel filter is about empty, where it was about 3/4 full when idling high. thoughts appreciated -jeff
 
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