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

[clarrance]

Are you getting any spark at all at the plugs or points? Possibly jumped time when it backfired. What kind of carb are you running? Also check the larger wire that goes through the loop on the back of your amp meter. I had an issue once where the factory connector wasn't making a good connection and it did all kinds of crazy things including frying a new EI module

 

[Rmally]

Here's a few pictures of the points.

Also pictures of the coil, alternator, wiring......does anything look suspicious?

So now I have fried the Pertronix and a set of points.

 

[clarrance]

Where is your ground cable connected from the battery? It needs to be connected directly to the engine block, then a ground strap from engine block to frame & body.

 

[Rmally]

The ground or Negative cable (which is a red cable, PO put on and I have never changed) is going to the engine block. I don't believe there is a ground strap to the body.....going back out to garage to check. Do all vehicles have the ground strap?

 

[Rmally]

Ok, I may suck as a mechanic but my detective skills are spot on....I did notice that the negative cable is grounded to the block, however there is no grounding strap.

Here's the WEIRD part.....I just replaced the burned out points and could notice when I was setting the gap that the points were actually warm and getting warmer....not hot just warm. Like an idiot I forgot to take off the negative cable but the coil was unplugged from the distributor.

I also noticed that the coil was warm, I then removed the negative cable and finished setting my gaps. I'm sure the Bronco will start, but now I don't want to put the negative cable back on because the coil and points start getting warm.......What the heck is going on?

 

[76MaBronco]

WOW!!! I've never seen points look like that before...that's a LOT of voltage...

If things are getting warm that means current is going through them to somewhere. First, disconnect the ground and put a grounding strap (or battery cable, something thick and beefy, if you have one laying around) from the block to the body. See if that changes the temperature issue of the points and coil once you reattach ground.

 

[Rmally]

WOW!!! I've never seen points look like that before...that's a LOT of voltage...

If things are getting warm that means current is going through them to somewhere. First, disconnect the ground and put a grounding strap (or battery cable, something thick and beefy, if you have one laying around) from the block to the body. See if that changes the temperature issue of the points and coil once you reattach ground.

Here is a series of photos that show what I'm up against.....The first one is how the points looked after I bought the Bronco, it ran fine but looks as if it was getting ready to fry this set.

The second picture is the Pertronix unit I installed that lasted about 4-5 weeks. I drove maybe 120 miles in that time frame with no problems, then one day just 100 yards from the driveway....boom.

The third picture is the most recent set of points I installed right after the EI burned up. The Bronco ran flawless for maybe another 60-80 miles then same as before, didn't even get out of the driveway when I blew 2 fuses....Replaced them then went two laps around neighborhood and BOOM...the big backfire and resulting points.

I just installed a new set of points and the Bronco fired right up and ran perfect....No test drive though as I'm scared to death it will result in another "Big Bang".

What to do, what to do.......Where's that cliff.

PS....Will add grounding strap tomorrow and see what happens.

 

[clarrance]

Check out this wiring diagram for your Bronco. Trace back from fuseable link and points. Maybe you will find something after reading through the diagram.

http://oldfuelinjection.com/?p=19

 

[Viperwolf1]

Are you using an ignition resistor? No resistor will increase the coil and point current until one of them fails. Might want to check for voltage at the coil when the key is off too. Shouldn't be any.

 

[oldiron]

Been on the phone with randy, He has 13.6v at the battery with the engine running at idle...but has 16.6 at the positive terminal of the coil with the engine running. engine off and the key in the run position coil has 5.9-6.2v. How is this possible?
Greg

 

[Viperwolf1]

Been on the phone with randy, He has 13.6v at the battery with the engine running at idle...but has 16.6 at the positive terminal of the coil with the engine running. engine off and the key in the run position coil has 5.9-6.2v. How is this possible?
Greg

I'd guess that the alternator charge wire has high resistance somewhere between the alt and the starter solenoid. The voltage regulator senses charge voltage at the starter solenoid and it is probably maxing the alt output voltage to get that 13.6v there.

6v in run is normal.

 

[oldiron]

Could that explain 16V at the coil+ while running only?
Greg

 

[Rmally]

Greg and Viper,

Thanks for all the help, What should I do to try and correct this? Is there something I need to re-wire, replace, etc. Do I need a new alternator?


In summary here is what's been done and measured so far:
======================================

Key off battery reads 12.6 and the coil is 0.0

Key in on position but not running coil measures 5.9-6.2

Engine running battery reads 13.6 and the coil reads as high as 16.9, but jumps around with readings as low as 14.8, 15.5, 16.2, 16.9.......this is all at idle speed.

I have replaced the voltage regulator.

I have replaced the Negative battery cable and its ground at the block.

The new points are in and the Bronco is running perfect....except for the high readings at the coil which will eventually fry my points again.

Just need to know how to remedy this problem at the coil.

Many thanks again.

 

[dave67fd]

Edit: sorry posted before your last post

Maybe try to Print out the correct year for your truck from Post #28. Carefully trace the ignition portion wiring with a highlighter the best you can. Use blue painters tape and mark the wires as you go.
Hopefully that will clue you to something that maybe out of wack or at least confirm your wiring is intact. Make sure all the push on connectors are clean and free of corrosion with no broken pins/sockets. A squirt of WD and a wipe down helps.
Do as mentioned and run without the alternator obviously after you replaced the points/condenser.
I will assume you did replace the condenser with the new points and replace them each time the points get fried. Points are typically damaged because of bad condenser and omitted ballast resistor but i'm sure you have more than that going on because of the severity of the point damage.

 

[dave67fd]

As viperwolf mentioned earlier, confirm your using a ballast resistor.

 

[Rmally]

Help the Rookie......Where is the ballast resistor located and what does it look like. I'm looking in my cheap off the rack manual and it doesn't show it.

Thanks,

 

[Blue Bastard]

The cylinder looking thing thing at the top of the voltage reg in the picture . I thnk....

 

[Viperwolf1]

The resistor is actually a pink wire between the ignition switch and the firewall which goes on to become the green-red wire at the coil. 6V at the coil kinda confirms you have one.

To test my theory on the bad alternator charge wire do this. Disconnect the battery. Remove the existing alternator charge wire (10g wire) from the rear of the alternator and isolate it so it doesn't touch ground. Run a new one from the alternator to the battery side of the starter solenoid. It should be at least 10g. Connect the battery, start it and test voltage.

 

[Rmally]

Will do Viperwolf1,

I did look under the dash....wow what a mess and some exposed wires.

The pictures are not the best as I'm not a Yoga pro who could fit up under there but take a look at these. It looks like the PO has been doing something under there.

The wires from the ignition switch are spliced in with another that vanishes into the wiring harness. Looks like a red/blue wire into a white (unless that's the pinkish wire, I really can't tell). I'm sure this is not good having bare wire showing......Thoughts? (Picture number's 1-2-3)

Also, there is another frayed white wire going into a black rubber block....it's barely still connected...what is this? (picture #4)

 

[Rmally]

OK, I did the alternator charge wire test and it made no difference....actually I got a few higher readings which went into the 18.4 range. They were all between 15.4 and 18.4

Ideas?