Save me $3,000 or help me push my Bronco over a cliff....

[Rmally]

First of all.....I'm calm. Set backs are expected when you mess around with 40year old vehicles but this problem I'm having is driving me to drink. (not really)

I was set to go ahead and bite the bullet and spring for a new wiring harness, however the mechanic that last worked on the EB said to wait till he could come by and check some things. He was here today and while we couldn't find any "bad" wires he did say 15.5 to 16.4 volts was way too high so we replaced the voltage regulator.

He said before I spend all that $$$ on a new harness we need to ID the problem because we could wind up ruining the new harness....so maybe this $21.00 voltage regulator would save the day. Fired up the engine and got a consistent 14.2-14.4 volts even upon high rev's.....Hmmm, maybe this was the problem all along. We hop in and take a test ride around the neighborhood.....oh baby its running great, we go around a second time and as we start up a hill....BOOM......the loudest backfire in the world occurs, were talking window shattering, 356 magnum, cannon fire BOOM backfire. 3 neighbors came running outside because they thought the telephone pole transformer had exploded.

We tow the EB back to my garage and of course the fuses and bulbs are toast.

So, now I want to just push it off a cliff because I have no idea what's going on or how to fix it. Maybe I can trade it in for a moped....at least I can peddle that home. I have absolutely ZERO confidence in the EB and I hate that feeling.

Ideas.....

Randy

 

[DuctTape]

I fought a backfiring problem recently that turned out to be a bad coil and a bad ignition module. It was probably my fault as when I was doing wiring I left they key in on position a lot figuring shit out.

Apparently feeding power to a pertronix elec ignition module without running the engine fries the module. If I have to monkey with electrical problems again I will be sure to disconnect the coil and module.

It was a $140 mistake... not the biggest mistake I've ever made, but not the smallest.

 

[DuctTape]

And I feel you on the confidence. I "finished" (ha) my frame off this winter and I'm just now starting to trust it. Expect things to go wrong but know that eventually you will find all the gremlins (well, they will find you). I'm planning on increasing my ranging and try to get all the bugs out, and I know (and by I know I mean I tell myself) that eventually bob will indeed be my uncle.

 

[Rmally]

The backfire really isn't the issue, it was just an unpleasant side effect. Why in the world am I having these "surges" that keep blowing fuses and bulbs.

Why did the Bronco backfire when the main fuse blew? Would all this go away with a new harness......?:??:??:??:?

Funny thing is, I had been driving the Bronco most of July and August with no problems.


Thanks Duct Tape for the words of encouragement.

 

[Sniper]

may be worth replacing the regulator on the back of the instrument cluster.

 

[73azbronco]

IVR, same thought. That and check voltage to coil in run and start, see if you have the right voltage at the right time. Grounds check as well. Recheck regulator alternator output, might be again, grounding issue. What ever you do, do NOT look at the valve cover gasket or you'll be here for eight years.http://classicbroncos.com/forums/showthread.php?p=1759569#post1759569

 

[dave67fd]

Nothings imposible but i would doubt the instrument regulator is at fault. It only regulates the instrumentation so if you don't have any abnormaly bouncing gauges or inaccuracies it should be fine. I remember in your other thread you mentioned your fuel gauge wasn't reading the same so changing it may help in that regard.

My guess is whatever is causing the power surge is also surging the pertronix causing a quick change in timing/dwell creating the backfire.

I will also assume you have the Pertronix I and not the II. The II can withstand reverse polarity and current protection where the I doesn't. As mentioned leaving the key on (not running) can damage or make the Pert. I work incorrectly.

If you love your Bronco (although they can be frustrating as can any old vehicle) you will be patient, take your time to learn the system and search for problems. Disconnect the battery and run the entire harness down with a bright flashlight, including getting on your back behind the dash, check/clean your fuse block, they can corode quite easily.

What alternator are you using? Is it wired correctly? What condition is the regulator connector and contacts in?
There's many things that can be causing the issue. Including getting a second bad regulator.
It can become daunting at times. Be patient you will figure it out. If you do decide to replace the harness make it your last resort. There's nothing worse than replacing the harness and then finding another small overlooked problem that was the cause.

 

[BRONCROB]

JUST PUSH THAT THING OVER TO MY HOUSE AND RID YOUR SELF OF THE HEADACHE;D NO REALLY THOUGH....YOU MAY WANT TO GET A WIRING DIAGRAM AND ELIMINATE ANY NONFACTORY WIRE SPLICES AND MAKE SURE NOTHING HAS RUBBED OR MELTED AGAINST SOMETHING.THIS SOUNDS LIKE A HARD TO FIND SIMPLE PROBLEM.ALSO MAKE SURE YOUR BATTERY GROUND IS CONNECTED TO YOUR BODY,ENGINE AND FRAME.14v SHOULDN'T BE BLOWING YOUR BULBS OR FUSES AND I DON'T THINK 16V WOULD EITHER,BUT I COULD BE WRONG.

 

[Ranchtruck]

If you're having massive voltage spikes, then the problem is somewhere in the alternator circuit. If the ground path between the alternator case and the battery is weak, you can get the regulator trying to max out the alternators output and not seeing the battery voltage come up. Then vibration makes the ground circuit work better momentarily and you get a voltage spike before the regulator can react and back the output down. Same with the positive side circuit between the alt and the battery and the reference circuit that feeds the regulator.

Learn how to do voltage drop tests across all the main circuit points in the charging system while it's running under load. Fan/headlights/ect on.

Just as a side note, there were a lot of 01-04 Honda Civic ECU's taken out because mechanics wouldn't tighten the alternator mounting bolts enough after replacing belts.

 

[broncnaz]

What fuses and what bulbs got burnt out? Id look at those systems/wiring closely. Fuzes dont blow out because of voltage its amperage that causes them to blow and a short circuit is about the only thing that will cause a high amperage condition. Most automotive fuses are rated to 32 volts and I believe a lot of the older glass fuses in broncos are rated to 125v. but its still the amperage that causes them to blow no matter how much voltage. Id look at the wiring. Make sure all your grounds are good.

 

[Viperwolf1]

Make sure the regulator is grounded well too.

 

[xcntrk]

Personally, I'm a fan of the rewire option. I just did a complete rewire recently and there's nothing like knowing the in's and out's of your wiring system top to bottom having completely refreshed and installed all new. Also keep in mind with a rewire you're not replacing the stock antiquated harness with the same thing; instead you're adding in a better overall harness with more circuits , proper isolation, and improved protection against electrical faults. So even if you did have a problem like this in the future it would be more contained an easier to troubleshoot. Complete harness + internally regulated alternator and even new column wiring if you wanted to be thorough and you'd have a 21st century electrical system in a 20th century vehicle.

 

[DuctTape]

Personally, I'm a fan of the rewire option. I just did a complete rewire recently and there's nothing like knowing the in's and out's of your wiring system top to bottom having completely refreshed and installed all new. Also keep in mind with a rewire you're not replacing the stock antiquated harness with the same thing; instead you're adding in a better overall harness with more circuits , proper isolation, and improved protection against electrical faults. So even if you did have a problem like this in the future it would be more contained an easier to troubleshoot. Complete harness + internally regulated alternator and even new column wiring if you wanted to be thorough and you'd have a 21st century electrical system in a 20th century vehicle.

X2. The painless / centech kits aren't cheap (600-700 bucks) but there are other, more generic kits that are half that or less. Depends on how much time/money you want to invest but I agree wholeheartedly with the sentiment that there is no substitute for doing the work yourself - if you do you will know the rig inside and out.

I went painless because I had never done a full rewire before, but it was so easy if I did it again I'd go with a cheaper universal kit.

 

[strokers]

I would try disconnecting alternator and at cruise it around on battery for half hour or so. Repairing 1 circuit (charging) isn't that bad. Oh and you wouldn't need any witnesses I mean help pushing over cliff.

 

[strokers]

I would try disconnecting alternator and at cruise it around on battery for half hour or so. Repairing 1 circuit (charging) isn't that bad. Oh and you wouldn't need any witnesses I mean help pushing over cliff.

 

[SteveL]

Im no fan of those pertronix. The wifess 66 had one when she bought it. Any time she hit traffic it would run like sh^t if it would run at all. We swapped it back to stock and all the problems went away. Now its got a 351w with an hei dizzy.

 

[DuctTape]

Im no fan of those pertronix. The wifess 66 had one when she bought it. Any time she hit traffic it would run like sh^t if it would run at all. We swapped it back to stock and all the problems went away. Now its got a 351w with an hei dizzy.

If mine goes again I will ditch it too. Did you go back to points or a different electronic ignition vendor?

(Sorry for the mini hijack)

 

[Rmally]

I dumped the EI when it got fried so it has the points back in.

I haven't tried disconnecting the alternator and running on battery to see what happens so maybe I can try that this weekend.

The only warning I get when it's about to blow is the engine starts running rough or bogging down.....then Boom! When this happens the 30 amp fuse to starter blows, the fuse in the glove box that controls turn signals blows, and the rear turn signals and brake light filaments in the bulbs are destroyed.

I can replace the fuses and the Bronco will run great for 2 mins, 2 hours, 2 months....who knows. Very frustrating and with my electrical skill not very hopeful

 

[OklahomaBroncoB]

I dumped the EI when it got fried so it has the points back in.

I haven't tried disconnecting the alternator and running on battery to see what happens so maybe I can try that this weekend.

The only warning I get when it's about to blow is the engine starts running rough or bogging down.....then Boom! When this happens the 30 amp fuse to starter blows, the fuse in the glove box that controls turn signals blows, and the rear turn signals and brake light filaments in the bulbs are destroyed.

I can replace the fuses and the Bronco will run great for 2 mins, 2 hours, 2 months....who knows. Very frustrating and with my electrical skill not very hopeful

Just replace all the fuses with aluminum foil, problem solved!

 

[Rmally]

Quick update......Re-checked wires and replaced the fuses and now the Bronco won't start. It just spins and spins. When it had that massive backfire I can only assume that it's done something. Before, I could always just replace the fuse and it would fire right up and run until it puked fuses....now it won't even catch or start...just turns over and over and over.

Where should I start on getting it to fire.

I tried starting fluid but still nothing.


EDIT......Just looked closer at the points and guess what...They are fried! I didn't notice earlier so at least now I know why it won't crank.

If your looking for a EB you may find mine listed soon in the classifieds.....