I think I made the wiring problem worse!

[Troy]

While my Challenger's (1970) transmission was being rebuilt, I decided to try to chase down a few electrical issues and install the electronic tach and clock upgrades. Well, I found the gauge cluster had already been rebuilt and upgraded so I just reinstalled it - hopefully the same way I did the last time when I had it apart to change the bezels.

The car had experienced intermittent starting problems throughout last summer - usually when it was hot. Like on a long road trip or sitting in show traffic in 95+ degree weather. Car would start but immediately die when the key returned to "run". The last time it happened I had determined that the blue wire (ignition 1 or 2) was not providing power to the ballast resistor. The ballast resistor, orange box, and coil were all fine. At that time (probably for the worse), I was 300 miles from home and I connected a lead from an ACC terminal on the fuse box to the *brown* wire (which generally only has power in the "start" position) inside the car. Any way, I got the steering column apart and found a new switch. After poking around with the multimeter I found that the switch was fine and that I was getting 12 volts through the bulkhead connector - but not to the ballast. The engine wiring harness is all neatly wrapped so I couldn't trace the wire easily - although the factory diagram shows a splice somewhere which powers several other components. I ran a jumper wire from the bulkhead connector to the ballast and it solved that problem (ballast output has power in "start" and "run"). I need to check the voltage to see if it's correct though. I checked the coil and it was getting power. Car would turn over but not start. I had some spare parts so I swapped the ballast (no change) and the orange box. At that point it fired and I let it run for a few minutes. I shut it off to tie up all the wiring and reattach the fuse box. No start after that. I pulled the cap and rotor and they looked a little worn so I replaced them. I pulled the coil wire and it had spark (orange) and the #1 plug wire did as well. I bought and installed an MSD Blaster coil last night and the car started right up. I'm thinking that I may have burnt out the old coil with my rewiring job (effectively brown and blue wires powered all the time)?

So, now the car runs but when I took it for a drive it would "cut out" right after I'd mash the gas pedal. It would roar (Six Pack) and accelerate for a second and then it was like someone pulled the plug. As soon as I let off the gas it would go back to rumbling down the road. Once I got a pop that sounded like a backfire through the carb. So, I can drive, idle, etc. but no hard acceleration.

Additionally, my tach no longer works and neither does the fuel gauge. When I first tried starting the car the fuel gauge would peg all the way to the right past full but, after I "fixed" the ignition switch wire it disappeared (not sure which side) and hasn't moved since. I can see regular spikes in the ammeter - about once per second or so it will bump about 1/8" over to charge. The dome light will dim at the same time and the radio (aftermarket) keeps resetting itself. The radio and an auxiliary power plug are run from their own source (I believe) so whatever is causing the pulse feeds both. The headlights are on relays and don't seem to flicker.

So, any ideas on the engine cutting out? Is there something important that I may have bypassed with the blue wire that killed the power to the fuel gauge and tach? Any ideas on the pulsing? I know the wiring is messed up but I didn't change anything that didn't work when I parked the car over the winter. I'd hate to catch it on fire and I want to get on the road again - as soon as it dries out!

Troy

[70charginglizard]

Sorry to hear your having electrical probablem again Troy.

Seems to be the trend with everyone this year...

I finally got fed up with it all and replace the entire interior dash harness. Everything seems to be great now on mine. I made sure when connecting everything back up at the bhd connection and under the steering column that everything was clean and very tight.

If I were you I'd be very suspicious of the two ignition connection points.
One: under the steering column
Two: up at the bhd connector thru the firewall.

If your still running it with your old dash harness and are not afraid to bypass...then I would pull the blue/white wire completely out of those two connection points and run them around those connection points seperately with a soldered connection of the wires at both locations.

That is a very weak point in these cars. Especially regarding that ignition wire. I'm sure my issues were either at those location or someplace nearby them.

You can probably clean the connection locations up at these and try using some electrical grease to help make contact if you dont want to do what I show above but you may just dealing with this issue again soon after later on.  

Your call.

Double check your gage cluster is well grounded. That will cause all kinds of problems like you mensioning above if it isnt. I even ran a seperate little ground wire off my tic toc tach lower outbd mounting screw down to the dash frame below it and that really helped.

[Troy]

I know the wiring is hacked but I have a million projects (that will likely cost me millions of dollars) to do first. There were only a few minor issues before. I've had the gauge cluster out at least 3 times and never had the gauges act like this. I'll probably add a new ground wire just to be sure but the fuel gauge did work at first when everything was back together. I didn't mess with any connections to the cluster itself when I moved the ignition wire.

I've already verified that the ignition wiring connections inside the car are doing what they are supposed to be doing. The engine harness appears to definitely have something wrong though. I believe the jumper wire I made for the blue one solved that particular issue BUT it might not be tight or have the world's greatest connection once the car is in motion. It was a temporary solution just to see if that solved the immediate problem (no start).

Troy

[70charginglizard]

I hate to say it then but I bet you have a melted short somewhere inside the taped up portion of the engine harness more then likely. did that engine ever get really hot at some point? You know evens wiring sells new engine harnesses pretty cheap. you may want to consider a new one with him Troy.

Otherwire your probably going to zacto open up the engine harness and see whats going on inside that sucker. 

[Nacho-RT74]

damn... Troy, I have had so tired lately that get into long post makes hard to me and a headache, so usually I'm making short deals... but I PROMISE to you than tomorrow will try to read with details and if is posible to help will do.

( I hope not to get a phone call to f**k up my day tomorrow )

[Nacho-RT74]

Ok, read everything.

This is the tipical power miss somewhere between ign switch and sources, then MAYBE the temporally fix yes, could damage the rest. Lets try to fix that first.

the main system need to be revised. We have a blue(traced on some sections) wire what runs from ign switch up to the engine sources here is a basic diagram ilustrating that

[Nacho-RT74]

Then we have the brown wire what ON 70 STILL TURNS OUT BLUE AFTER BALLAST ( after 71 all the wire was brown, diagram is 71 and lates based )

not ilustrated, but brown wire runs from ign switch, a straight and one line between column switch and bulkhead

[Nacho-RT74]

Both, blue and brown wires are allways hot due the ballast is working as an splice although both are feeded at diff moments from ign switch ( Run-blue, Start-brown ). Both at diff voltage readings due the side where the ballast is being directly feeded from ign switch ( thats why the brake ligth on cluster dimms out when cranking ). IF you want to know which wire is not working with precision, unplug the ballast and check each one.

If you burn the coil is because you bypassed the ballast feeding at the side where the brown wire is spliced for long time. If you want to feed the ballast keeping safe the coil, the side being feeded from batt must be the blue splice, as far ballast is good. If not, then ballast is damaged and in an emergency without an spare, you can feed the brown side OR even directly the coil, BUT THATS UNTILL ARRIVE TO A PARTS SHOP AND REPLACE.

Note on this, even cutting off the ign switch, engine will keep running, so to turn off the engine this jumper wire must be disconnected

So now, the only way to be sure about this is check carefully both of these wiring lines

Tach and Fuel Gauge... Dunno on Challies but on Charger with standart cluster the Fuel Gauge is feeded from the run circuit, and on rallye clusters, the fuel gauge is feeded from Accesories circuit. Both cases going through limiter. Tach is feeded from Acc

do you have some other fail on gauges ? idiot lights ?

[Paul G]

As always, Nacho's drawings help a lot. You may have fixed it by now, I don't know? I have been an industrial electrician for over 30 years. So with that experience let me tell you everything must be checked twice, or even 3 times. Intermittent trouble is the worst to find. I would think you have a lot of things going on, not just one problem.

The car had experienced intermittent starting problems throughout last summer - usually when it was hot. Like on a long road trip or sitting in show traffic in 95+ degree weather. Car would start but immediately die when the key returned to "run". The last time it happened I had determined that the blue wire (ignition 1 or 2) was not providing power to the ballast resistor. The ballast resistor, orange box, and coil were all fine. At that time (probably for the worse), I was 300 miles from home and I connected a lead from an ACC terminal on the fuse box to the *brown* wire (which generally only has power in the "start" position) inside the car. Any way, I got the steering column apart and found a new switch. After poking around with the multimeter I found that the switch was fine and that I was getting 12 volts through the bulkhead connector - but not to the ballast. The engine wiring harness is all neatly wrapped so I couldn't trace the wire easily - although the factory diagram shows a splice somewhere which powers several other components. I ran a jumper wire from the bulkhead connector to the ballast and it solved that problem (ballast output has power in "start" and "run"). I need to check the voltage to see if it's correct though. I checked the coil and it was getting power. Car would turn over but not start. I had some spare parts so I swapped the ballast (no change) and the orange box. At that point it fired and I let it run for a few minutes. I shut it off to tie up all the wiring and reattach the fuse box. No start after that. I pulled the cap and rotor and they looked a little worn so I replaced them. I pulled the coil wire and it had spark (orange) and the #1 plug wire did as well. I bought and installed an MSD Blaster coil last night and the car started right up. I'm thinking that I may have burnt out the old coil with my rewiring job (effectively brown and blue wires powered all the time)?


I would suspect a high resistance connection in the blue wire circuit since it keeps the engine running after start up. Could be poor ignition switch contacts, sometimes okay, sometimes not, bulkhead connection, or just a crispy 40 year old wire. Don't trust reading it good one time as it is always good. (Ask me how I know) I would open up that wiring harness and inspect the wiring. It can be re-taped easily.


So, now the car runs but when I took it for a drive it would "cut out" right after I'd mash the gas pedal. It would roar (Six Pack) and accelerate for a second and then it was like someone pulled the plug. As soon as I let off the gas it would go back to rumbling down the road. Once I got a pop that sounded like a backfire through the carb. So, I can drive, idle, etc. but no hard acceleration.

Could be poor power being supplied to the ignition system, specially if the ignition switch is flaking out once in a while, wires crispy under that old tape or through the bulkhead connector. I would think a good look at the bulkhead connector is in order. Especially check the batt and alt wires where they run through it if you have not done that already. I would not be surprised if those connections are not heat warped and brown. 

Additionally, my tach no longer works and neither does the fuel gauge. When I first tried starting the car the fuel gauge would peg all the way to the right past full but, after I "fixed" the ignition switch wire it disappeared (not sure which side) and hasn't moved since. I can see regular spikes in the ammeter - about once per second or so it will bump about 1/8" over to charge. The dome light will dim at the same time and the radio (aftermarket) keeps resetting itself. The radio and an auxiliary power plug are run from their own source (I believe) so whatever is causing the pulse feeds both. The headlights are on relays and don't seem to flicker.

The instrument voltage regulator pulses on 12 volts which ends up being somewhere around 6 volts to the gauges. If your gas gauge is pegging sounds like it was getting more than 6 volts. To check that put a volt meter on the temp sending unit wire since it is easy to get to and read your voltage to ground. Should be a pulsing 6 or so volts. That ammeter pulsing could be a bad connection, bad ground, or the voltage regulator could have a bad ground, or being going out on you. Some things to check.

So, any ideas on the engine cutting out? Is there something important that I may have bypassed with the blue wire that killed the power to the fuel gauge and tach? Any ideas on the pulsing? I know the wiring is messed up but I didn't change anything that didn't work when I parked the car over the winter. I'd hate to catch it on fire and I want to get on the road again - as soon as it dries out!

Troy

[Paul G]

I just thought of something. Set up a volt meter under the hood somewhere so that you can see it from behind the wheel. One lead on battery neg and put the other at different points to test your voltages. Blue wire, brown wire, etc and see what happens to the voltage as you trun the ignition switch. jiggle that switch back and forth and see if the voltage holds true during start and run, etc.

Just a thought.

[Paul G]

Does that Blaster coil need the resistor?

[Nacho-RT74]

any coil on standart ign system requires resistor to save from overheat because they are constantly getting power from ign switch. MSD ign modules not because they are feeded just when closing circuit FROM module on BOTH leads

[Troy]

Back to this - I had to take a few days away from it before I put a wrench through the windshield...

I'm chasing multiple problems so I was working on this first:
http://www.dodgecharger.com/forum/index.php/topic,81202.0.html

I've crawled all over the car with a multimeter it seems. I cut all the tape off the engine wiring and traced each wire.

With the car off: In "start" I have 12 volts on the brown wire at the ballast. In "run" I have 12 volts to the ballast resistor and orange box. I have 4 different ballast resistors and all register 1.2-1.3 ohms. However, when I check the voltage on the other end of the ballast in "run" I'm only seeing 3.7-4 volts. This should be higher than 8 I believe. Why is it dropping so much through the ballast? I know the "electronic ignition kit" comes with a .8 ohm ballast but it says it's for working with the stock "points style" ignition. I can't seem to find one locally. The chrome box takes a .25 ohm ballast but it's not for continuous duty. When I run a straight 12 volts to the coil the car runs great but the coil gets really, really hot (like it will burn you and takes 2-3 hours to cool down). I'm also not seeing a "pulse" on the negative side of the coil (and my tach still doesn't move).

I pulled the engine harness plug from the bulkhead connector and all the terminals were clean with dielectric grease still on them. I haven't pulled the bulkhead connector from the inside yet - I'm hoping to not have to pull everything out of the dash again! I can try bypassing the connector to see what happens I suppose.

The fuel gauge on the Challenger is fed by the voltage limiter in the cluster. The water temp and oil pressure gauges tap the same wire and they seem to be fine.

I added a ground strap from the engine to the firewall. No difference in anything. I tried adding a ground from the gauge cluster to the dash and didn't notice any difference there either. My wipers no longer "park" and I know that can be a symptom of a flaky ground.

Thanks for all the help so far!

Troy

[nascarxx29]

I ve got a techinal service bulletin on the wipers that had a fix for wipers that wouldnt park.They sugggested cutting a certain wire I read somewhere .I had same problem and tapped the wiper park plate with a rubber malet lightly and they parked .There are points and contacts behind the plate.And those park plate wires had a fine cloth insulation that wears off and the wires touch each other

[nascarxx29]

http://www.hamtramck-historical.com/images/TSBs/1969/69-8-14_page1.jpg

http://www.hamtramck-historical.com/1970-Dodge-TSB-Index.shtml

http://www.hamtramck-historical.com/1969-TSB-Index.shtml

[Troy]

Uh oh. While not directly finding an answer to the weirdness, I noticed mention of frying the gauges when there isn't a proper ground. It's possible (although I don't remember doing it) that I flipped the key while the cluster wasn't installed in the dash. I try to avoid anything like that since I'm not comfortable with the idea that the ammeter wires might bump something and weld the cluster to the dash. Is it possible that I killed the clock, tach, and fuel gauge with such a rookie move? Or could the same thing have happened if I didn't have the cluster grounded well enough when I did get it installed? (see parking problem above) I know I was looking at the fuel gauge when it spiked which means it had to be facing me (if you have the harness hooked up you can only twist the cluster towards the passenger seat so none of the gauges would have been visible). I may need the tach and clock rebuild kits after all...

Troy

[Troy]

Sigh... with the battery charger connected to the car I have 14ish volts on the brown and blue wires from the switch all the way to the ballast resistor. With a .8 ohm ballast I have right at 12 volts at the exit of the ballast resistor. I have 12 volts at the + post on the coil. With the battery charger off, I have 12 volts at the brown and blue wires and about 9 at the exit of the ballast resistor. However, when I start the car, I see 12 volts going to the + post on the coil while the starter is engaged and then about 4.4 volts once I let off the key (and the car promptly dies).

After inspection, it appears the engine harness is new(ish). I'd have to dig through the receipts to figure out where it came from. The dash harness is original - and slightly hacked as mentioned earlier. I pulled the connectors and they all looked clean and tight.

I noticed something once (and only once). When I had the ballast unplugged I had the voltmeter on the It looked like I had about .7 volts on the brown wire with the key in "run". That should have been 0 right? I didn't check to see which direction the current was flowing but I don't think that would cause this particular problem.

Any way, I've read a lot on the subject and it seems like there are a whole lot of people running performance coils with the stock orange box and no ballast. I can tell you the coil definitely gets hot but it doesn't seem to cause any other problems. I'd still prefer to fix the problem the right way. Currently the car is idle due to other problems so I kind of keep switching back and forth trying to get it all working again.

I've decided that I probably killed the tack, fuel gauge, and clock with my grounding problem. At least now my $250 in upgrades won't go to waste (thankfully I hadn't installed them the first time!).

Troy

[Paul G]

Blue is the run wire, brown is the start wire.

Basically the start wire bypasses the ballast resistor during starting to give full voltage to the coil during starting. When the ignition switch transfers to the run position voltage is now going through the ballast resistor to the ignition coil. The resistor drops the voltage down to "economize" the circuit. It draws less power and less heat through the ignition coil.

It sounds like in the run position you are dropping the voltage way too much. Try this, run a temporary 12 volt hot wire directly to ballast resistor 12 volt side. The side with the blue wire on it. With the temporary 12 volts on the resistor you should get around 8 volts out of the resistor, brown wire side. With the temporary wire connected start the car. If it runs you have a problem maintaining 12 volts to the blue wire at the resistor. Could be the ignition switch, wiring, or bulk head connector. (I know you checked them already) Could be the ignition switch not transitioning from start to run mode correctly.

Keep in mind you have the car "hot wired" and it wont shut off till you disable the temporary wire. (this was common mod in the sixties  )

If it still dies with the temporary 12 volt wire connected you could have a problem with the ballast resistor dropping the voltage too much.

Or, I am all screwed up and have you doing a bunch of stuff that wont help??

Just out of curiosity have you checked the wiring inside the distributor? Make sure that wiring in there is not chaffed, shorted to ground or something like that.

BTW, .7 volts is most likely a transient voltage, anything that small is virtually zero.

And one more thing, If the wiring has been hacked, make sure the brown and blue wires at the resistor are the same brown and blue wires at the ignition switch. Make sure they didn't get crossed to some other brown or blue wire.

[Troy]

Yes, I know what they are all supposed to be doing. I already cut open the harness and traced all the wires and they are in the correct places. Yes, I'd agree that the ballast is dropping too much voltage - but five of them? Three straight out of the package and one that I pulled off the Charger. And, why didn't it drop the voltage like that when it was on the battery charger? Could there be some issue in the alternator that interrupts the circuit? (Just trying to remember what is downward from the ballast.)

I have run a secondary wire in addition to the blue wire - but it was fed from the switch at the bulkhead connector (so inside the engine compartment). Same issue. When I run this wire directly to the splice with the brown wire (bypassing the resistor) it holds a constant voltage and the car runs - although this is where I worry about frying stuff even though the MSD coil is designed for 12 volts. I will try running one directly from a hot source (battery?).

If the wiring in the distributor was messed up it wouldn't run at all would it? I can make the car run just by bypassing the ballast.

Troy