Pirate 4x4 banner

1970 Bronco problems....

3K views 16 replies 11 participants last post by  Diablorides 
#1 · (Edited)
I bought an old 70 Bronco about 2 months ago. I've been using it as my dd to go to school and back. On wednesday I was driving to my final and it started sputtering on the freeway. Like I was running out of gas. So i switched to the front tank (which I know was full), and it still kept sputtering. So I ditched school and drove home. By the time I got it to the driveway it just died.

After I got it up to my parking spot (with a lot of friends). it fired up.

i checked my battery terminals, cleaned them, tightened them. Still nothing.
took off my alternator and got it tested. it's still good.
changed my starter solenoid
changed my coil
changed my ignition cylinder (old one was cracked anyways)

I just got it to turn over by crossing the solenoid. I'm lost as to what the hell it could be?

my only guess, is that a wire grounded out possibly? there are random wires everywhere... any ideas??
 
See less See more
#2 ·
Fuel, air, spark.

Pour a little fuel in the carb, just a little, and try to start the motor. If it cranks you have a fuel problem, likely a clogged fuel filter.

Look at your air filter. If it's not covered in mud you probably have air.

Pull a spark plug. With the plug in the plug wire, ground the threaded part against the motor. Have someone turn the motor over. If the plug sparks you have spark.

Report back.

I'm guessing clogged fuel filter. A clogged fuel filter will make it feel like you are running out of gas. After the motor dies and the filter sits for a while, the clog will often loosen and allow the motor to start again.
 
#3 · (Edited)
Rust and debris in the fuel tank can clog the pickup, then drop away when it quits, similar to the filter as mentioned. Although switching tanks should have isolated that issue.

Old fuel hoses can collapse shut under pump suction for a similar effect.

Vapor lock, if the fuel lines are too close to a heat source (exhaust) the fuel boils and the pump sucks vapors.

You didn't mention any distributor checks. I had a loose wire to the points once that would cause random stumbling and shutdowns.
 
#5 ·
Broncojohn: I'm not running the stock carb. It has a new Edelbrock 650 on it (came with it when I bought it).

Quick&Dirty: I did check the distributor. I had one wire that was barely hangin on. I pushed it back on, but nothing has changed. I will check all of the fuel lines tomorrow. I also though of the vapor lock. I tried just taking off both gas caps and turning it on. Nothin.

recoiljunky: I'll do everything you said tomorrow. I got called into work today at 3. I was planning on tearing it all down tonight and isolating the problem. But apparently my manager has different plans for me. Thank you for the suggestions. I appreciate it. I know the air filter is good. I checked it out and it was pretty damn clean.

I'll try pourin some gas in the carb and checkin the plugs.

Thanks again guys.

-Cody.
 
#6 ·
Do you guys think it might be my voltage regulator? Because I have no power at all. My lights don't work or anything, even with a fully charged battery. I'm thinkin that a wire might have grounded out somewhere. Since my bronco only has like 5 fuses, a lot of different things are on one fuse. (all my fuses are good by the way). So does that narrow it down to just electrical?

When I got it to turn over I watched the fuel filter fill up with gas. Fuel system seems fine. It's gotta just be electrical....
 
#7 ·
sounds like voltage regulator could be the issue, I've had this happen on 2 of my older ford trucks. What color cap does yours have?
 
#9 ·
the old ford voltage regulars came in 2 different colors, black and blue caps.
 
#11 ·
Go back and look at the ignition switch and make sure it is right and tight.

For a voltage regulator, get one for a 77 Granada - it is the electronic type and will reduce the dreaded 'pulsing'.

What are your voltages at the ignition switch, the coil and at the headlight switch?

As a test you can pull the starter cable off the solenoid, then test the voltage at the coil again to make sure you have ~12V when the key is in the 'START' position, and ~6v in the run position.

Bad voltage regulator should not cause a 'non-start' situation. If you want to eliminate even the possibility, just pull the plug.

good luck.
 
#13 ·
Bad voltage regulator should not cause a 'non-start' situation.
It did on my 84. Would cause it to randomly die every now and then, no telling when it would start again. Then one day just stopped it from running.
 
#14 ·
My 74 did that for a while before I realized my fule line had come loose from a clip and was sitting by my exhaust. It was getting hot and then it would vaporlock the fuel coming through the line. Basically buring it in the line and casuing air to go to the motor.

May be something to look at.
 
#15 ·
Sounds like fuel filter. If it was vapor locked as soon as the engine cooled down it would run normally. I had a problem with dust getting in between my fuse and the holder and breaking the connection killing all ignition power.
Check for moisture in your distributor cap as well as the condition of the electrodes.
 
#16 ·
I'd check your fuel lines next to hot things - a buddy that I wheel with had problems with vapor lock on his 78' because the fuel line was too close to the exhaust...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top