1975 bronco sputtering while driving

Bferrari · Jul 1, 2014

Have you pulled your spark plugs to check them? Your plugs can tell you loads regarding what is happening in each cylinder. I would begin with the basics, look at the plugs, perhaps change the cap, rotor and wires. Failure of any of these items can produce issues. Are the plug wires burnt or grounding at all on the exhaust manifold? All things to check. Sounds like you have ruled out the fuel system so now you are on to spark and compression! I would definitely pull your plugs and look them over really good, make sure they are all similar in color. Let us know what how they look.

blubuckaroo · Jul 1, 2014

Also, you might try measuring the resistance of the plug wires. They can be damaged easily. There are so many types that it would be hard to know what they should measure but they should all be close to the same resistance. If you find one that has way more resistance, replace it.

mini73 · Jul 2, 2014

Bferrari said:
Have you pulled your spark plugs to check them? Your plugs can tell you loads regarding what is happening in each cylinder. I would begin with the basics, look at the plugs, perhaps change the cap, rotor and wires. Failure of any of these items can produce issues. Are the plug wires burnt or grounding at all on the exhaust manifold? All things to check. Sounds like you have ruled out the fuel system so now you are on to spark and compression! I would definitely pull your plugs and look them over really good, make sure they are all similar in color. Let us know what how they look.

Plugs look all the same and have good color. I need to look at the plug wires closer though. Maybe one of them is grounding out. The pug wire are not that old. I want to get a new cap but unsure what type I need. I know I have electronic ignition but what kind? Can anyone verify that I have a duraspark ignition or not? If I am replacing would it wise to upgrade so something different? I sometimes have to make sure the plug boots are all the way on the distributor cap. Like to get the msd cap that where the plugs go on the and then a plastic plate goes on afterward that makes it impossible for them to come out of the socket. Here is some pics of the engine bay. I know about the clear filter. I just put it on right now as it was the only new one I had and wanted to see the flow of fuel and see if it has any trash in the tank. Will change when I fix this problem and get it back on the road.

mini73 · Jul 2, 2014

Bump to the top!

Justafordguy · Jul 2, 2014

That does look like duraspark which was stock on a 75. It's a great system but they can fail. Some parts stores can still test the module but they are cheap and it's a good idea to have a spare anyway.

mini73 · Jul 2, 2014

Justafordguy said:
That does look like duraspark which was stock on a 75. It's a great system but they can fail. Some parts stores can still test the module but they are cheap and it's a good idea to have a spare anyway.

Ok thought it was. I looked at some of the local places and they have 2 different ones most of ru time. I got one awhile back ago to change when getting the bronco running but it was the wrong one I think. I plugged it in and the bronco would just turn over but never fire. I got the one with the blue plastic strain relief and I have seen where I need to have the same one I have which is a green strain relief. Why didn't the one I bought awhile back ago work? What makes the them different?

Bferrari · Jul 2, 2014

Looks like you have a butt connector on the green wire coming from your module which should be going to the negative on your coil. Check this connection and make sure it is good. Also, I agree that I would get another module, doesn't hurt to have one as a spare. You can get them on Rockauto.com for under 20 bucks. While you are at it, replace that cap, rotor and wires. You could get the module, cap, rotor and wires all for under 50 bucks which will hopefully be a cheap way to remove these items from the equation.

mini73 · Jul 2, 2014

Bferrari said:
Looks like you have a butt connector on the green wire coming from your module which should be going to the negative on your coil. Check this connection and make sure it is good. Also, I agree that I would get another module, doesn't hurt to have one as a spare. You can get them on Rockauto.com for under 20 bucks. While you are at it, replace that cap, rotor and wires. You could get the module, cap, rotor and wires all for under 50 bucks which will hopefully be a cheap way to remove these items from the equation.

Yeah that was there when I bought the bronco. It goes to the negative on my coil.
I stopped by auto zone to see about the ignition module. There are 2 that come up on the computer. Both look blue and I have already tried one and it did not work. The bronco just turned over and never fired off. The guy did find one that was for a 1975 F150 with a green plastic relief which is what I have on mine. Seen on here where if I replace it make sure I get the same color as they are wired different. Just not to sure if this will work since already have one that doesn't work. I want to replace the cap but I want to get the cap that has the male plugs on it instead of the ones that I have. Just look more secure. I put these wires on when I was trying to get the bronco running but intend to get a new set.

mini73 · Jul 3, 2014

Can anyone give suggestions?

Justafordguy · Jul 3, 2014

You will have to use the module with the green grommet because it is wired different. It is a 75 only module.

You can upgrade to the cap with the male plugs, just get a cap, rotor, wires, and cap adaptor for a 77 Bronco and they will fit fine.

mini73 · Jul 3, 2014

Justafordguy said:
You will have to use the module with the green grommet because it is wired different. It is a 75 only module.

You can upgrade to the cap with the male plugs, just get a cap, rotor, wires, and cap adaptor for a 77 Bronco and they will fit fine.

Ok thanks. I found an autozone that has the green module. Going to get it after work and see if it solves the problem hopefully. If not I'll get the distributer cap also.

mini73 · Jul 4, 2014

Got off work yesterday and got the Green control module that I found at a local auto zone. It was for a 1975 Ford f150 truck. Got home and put it in. I be damm if the bronco didn't run like it supposed to run!!! Finally after a few weeks and all the troubleshooting with the fuel system and I get it. Went driving it after putting a full tank of gas in it. Also got a stereo and finally put the speakers in that I had planed. Good day to drive around and enjoy my Bronco. Happy 4th of July to everyone and thanks for all the help. I can always depend on getting the answers here!!!!!!!!!!!;D;D;D;D;D;D;D;D;D

Bferrari · Jul 4, 2014

Congrats! Glad you got it fixed!

mac77 · Jul 5, 2014

Dang!

You beat me to it. I was just fixing to post saying it was more than likely the dura spark module. My '76 would run fine but after running a while and warming up mine would just die all together added a mad 6a and never looked back.

jcpetrson · Jul 7, 2014

Glad you got it fixed. I've been reading this thread since the start of your problems and learned a lot. There is some great support here.

mini73 · Jul 7, 2014

jcpetrson said:
Glad you got it fixed. I've been reading this thread since the start of your problems and learned a lot. There is some great support here.

Yeah there is a large amount of knowledge from members on this forum. If you have question just ask. Some one on here will know it.

Justafordguy · Jul 7, 2014

I'm glad the module did the trick. Now go get a spare and you will never have another failure again.

mini73 · Jul 7, 2014

Justafordguy said:
I'm glad the module did the trick. Now go get a spare and you will never have another failure again.

Got an extra now. The funny thing is this was the first thing I thought about replacing before I did all the troubleshooting with the fuel system and having this problem. . But thought I would start simple. Would of been simpler just to buy this the first! Oh we'll, got pretty good at taking the fuel out of the tank and removing the carb!!! Lol

pooch · Nov 14, 2018

mini73 said:
Got off work yesterday and got the Green control module that I found at a local auto zone. It was for a 1975 Ford f150 truck. Got home and put it in. I be damm if the bronco didn't run like it supposed to run!!! Finally after a few weeks and all the troubleshooting with the fuel system and I get it. Went driving it after putting a full tank of gas in it. Also got a stereo and finally put the speakers in that I had planed. Good day to drive around and enjoy my Bronco. Happy 4th of July to everyone and thanks for all the help. I can always depend on getting the answers here!!!!!!!!!!!;D;D;D;D;D;D;D;D;D

Reviving this thread. I am having the same issue with my 66. The carb is newer so I dont think that is the issue. When I start it the first time it just fires up. Subsequent starts I need to heavily pump the gas and it struggles to turn over but eventually does. Sometime going up steep hills and laying on the gas pedal I get the same type of sputtering and I think it is going to die but has not.

I am super non mechanical, what is this green control module that you speak of? I may need to look into this.

jcpetrson · Nov 19, 2018

Ignition Coil - The original poster's coil failed. He installed the wrong one even though it was listed correctly.

I had a similar issue and it was remediated also by replacing the ignition coil.

1975 bronco sputtering while driving

Sr. Member

Grease Monkey

Sr. Member

Attachments

Sr. Member

Bronco Guru

Sr. Member

Sr. Member

Sr. Member

Sr. Member

Bronco Guru

Sr. Member

Sr. Member

Sr. Member

Full Member

Sr. Member

Sr. Member

Bronco Guru

Sr. Member

New Member

Sr. Member

Similar threads