TheSkycrane

I have a 1967 dodge coronet with a 318 LA motor I pulled out of a barn, its a 440 trim level four door car. the car ran fine but had a miss, determined to be a burned valve or two. After rebuilding the engine i encountered a miss when the vacuum advance would engage the car would break up pretty bad. I put a different distributor in that I had and the problem went away. I had originally a 45 amp alt that needed a bearing, had it rebuilt and once i got it back it wouldn't charge, tried new diodes but no luck. After getting a new alt the following has happened. My old alt hooked up with just two wires the new one has an additional terminal I was instructed not to use. The alt just screams when the engine would run, after awhile it just went away. I checked all connections and connectors and didn't find anything even at the firewall connector. Then it would start and run but after about 5 minutes it would shut off completely, swapped carb, tested wiring and found the ignition switch to blame. After replacing that everything seemed to be just fine drove it around a few days no problems, UNTIL now. Car will start and alt still screams, but the car will not idle. I have replaced the following:
Starter
ignition switch
distributor
ballast resistor
alternator
points
condensor


Anyone got any ideas? I am stumped.

RacerHog

Tighten the drive belt for the alternator? maybe !!!

TheSkycrane

Yes the belt is tight.....


I was looking more for a hey, this intermittent problem happened to me and this is what it was. Or hey these are the resistance values and voltage readings you should be getting..

TVLynn

You have the later two field alternator. To use the two terminal alternator The unused field connection needs to be grounded to use it on your 67 charging system. Personally I would up date the system to a 70's system & use a later 2 field regulator

RacerHog

My Apology, My ways of helping are a little barbaric at times.

Hope you get her fixed and rolling soon....

440roadrunner

Not really necessary to use the later regulator unless you "fall into a deal" on one. The reason is that 99% of replacement 69 / earlier regulators are actually solid state. Look underneath the regulator. If there are two large wirewound resistors, it's the old mechanical relay type. If there is "nothing there" it's a solid state unit

TheSkycrane

Ok so I have a mechanical type regulator, pretty sure its the factory one, the alt was the original because it had the Mopar part number and was dated correct. When I got the car out of the barn I got it from every bulb was blown, which I thought was odd.

But tonight I did the following, dropped in a electronic distributor that I had with a coil and a ballast resistor and four pin ecu. I wired it up per my four pin diagram found in my Chrysler service manual and I still have the same result, engine starts Alt screams, engine will run as long as you keep your foot in the gas, but when you let off she won't idle.

Any other thoughts?

TVLynn

Bearing in the alt is seized

Boat Guy

Not sure what you are calling a scream, but if the regulator isn't regulating, the voltage could be too high and it could blow the bulbs by taking the alternator to an overcharging status. What is the output voltage of the alternator during this? Also did not see any comment responding to the post about the second field needing to be grounded. But first, check the voltage output while it's running. It might need a new regulator.

RacerHog

Check all the old hoses for leaks.......
Make sure all the vacuum caps are good...
Check to see if the PCV valve is the part making noise.....
Take the belt off and see if the scream goes away.....

440roadrunner

Good advice above.

Pull the belt and run a bit, see if it's belts, water pump, or alternator bearings. Turn the water pump, PS pump, and alternator by hand to "feel" for roughness, etc

MEASURE the running battery voltage. Cold it may be "different," but should not be higher than an absolute maximum of 15, 15.5 and that is a MAX

With the engine, regulator, warm and the battery "normal" battery voltage should run optimum at 13.8---14.2, not less than 13.5, and not more than 14.5

I would not be making a bunch of random modifications until you get things sorted a bit. Try to figure the "screaming." If you wired it wrong and the alternator is charging "max" the belt may be slipping, and battery voltage will be "way" high.

The carb / fuel system is SUSPECT.

Why did you change the ignition system?

Both the regulator and the ECU (ignition box) MUST MUST be grounded.

Scrape the mounting area and flanges clean, and mount with star lock washers. Bolts MUST be tight. If they are stripped, so whatever it takes.

TheSkycrane

Ok...guess I need to be a little more clear. I have swapped three carbs and I know those carbs are good. I know mines good. Car still runs like I have described. I can spray whatever type of fluid around my intake, I have no change in rpm, I have but one small vacuum line and whether that hose is plugged or not nothing changes, oh and my vacuum gauge says my vacuum is good. My fuel pump is pumping quite fine, in fact so does the electronic one I used to eliminate mine temporarily. My alt is not seized the bearing is not seized there is no roughness on it. And the belt is tight. My alt screams because the belt slips on the pulley, because the demand on the alt is too high for the alt to put out and the resistance is enough to allow the belt to slip. Still not the problem. I can remove the two wires from my alt and the car runs the same, the battery has passed a hydro test as well as a load test with my tester. All my other pulleys work fine and don't make noise. I switched the ecu temporarily into my car because I had the parts and I thought someone would try and tell me that was the best solution. It's not, the car still runs as described. My alt is grounded, my chassis has a good ground, my engine block has a good ground, my firewall connector looks great. I have continuity between all my wires. I have 12volts at my battery, I have 14.7 volts at my alt either one I use, I have 8 volts at one side of the coil, 12 at the other, resistor is in spec. I have spark at coil, at cap, at points, at plugs. I don't believe in just buying parts to replace things I obviously have a problem and I would like to diagnose and correct that problem rather than just buy a new part and the same thing happen later on.

RacerHog

So if I read this rite... 3 carbs and you still cant get it to idle. Every thing else if fixed at this point?
Is that where we are at.

But if the alt. is still screaming.... I would suspect at this point that you have the wrong width belt for the alternator.... Riding to deep in the pulley?

440roadrunner

[QUOTE=TheSkycrane;120634 My alt screams because the belt slips on the pulley, because the demand on the alt is too high for the alt to put out and the resistance is enough to allow the belt to slip. Still not the problem. I can remove the two wires from my alt and the car runs the same, the battery has passed a hydro test as well as a load test with my tester. .[/QUOTE]

Ok so let's be clear

You say you can "remove the two wires" from the alternator and it "runs the same."

Same as WHAT?

With the field wires removed, the alternator should NOT charge. This should change SOMETHING. Either the belt should stop slipping and or the battery voltage should drop

You say "belt slips on the pulley, because the demand on the alt is too high"

This does not make sense given your other statements

There are only so many reasons a belt can slip

The battery is low on charge

The battery is bad

There are a huge number of loads

Something in the charging system is causing the output to run wild

or there is something wrong with either the belt, or the pulley(s)

NOW

You say the battery has been checked with a hydrometer AND load tested. The hydrometer should show that the battery is charged? yes?

Loads.........I cannot imagine you have heavy loads in the car

If the VR or other wiring problem is causing the output to run wild, it certainly would not be running near 14V

What does this leave?

Glazed, wrong, defective belt, loose belt, or POLISHED GLAZED pulleys This last can slip by easily. A belt gets old, worn, loose oily. It runs "for awhile." Pretty soon, the pulleys are so slippery that No belt will work on them.

Another thought.........are all the brackets as per factory, IE the brackets have not been cobbled together?

Boat Guy

Lets fix one thing at a time. 14.7 volts is too much voltage for normal charge on an old style regulator. It should be around 13.5 when the car is running. Does the voltage climb with engine RPM? If so it is not being regulated. If not then there is a short taking the regulator to high charge. Regardless, I'd start by trying a different regulator. If that doesn't fix it, there is a short somewhere and the alternator is being taken to high charge to try and overcome the drain and you need to find that short.

Given the way the engine is or isn't running, I would suspect if there is a short it is in the ignition circuit. When the RPM drops low enough, the alternator can't over come the drain and it kills the ignition.

It takes 4 things to make an engine run; Spark, fuel, air, and compression. You have confirmed that you aren't running out of fuel and or air, so lets rule them out. You most likely don't have a valve problem or you would have other symptoms while the engine is running. And the rings don't sound bad or you would be complaining about smoke or some other symptom. So lets say compression is good. That leaves spark. We know you are having electrical problems and the spark is electrically generated. Lets fix the electrical problem and see if we can get a better idea of why the spark might be going away at idle.

At 14.7 volts wires get hot. It is possible that two wires have melted together and are shorting. Check your ignition wires. As stated with the wires to the alt. disconnected if the alt. is still screaming, there is a belt problem (since you have ruled out any internal alt. problem). Pulley misalignment and or wrong sized belt would be the best place to start looking. I doubt you would have missed a glazed belt. If it only screams when hooked up to the voltage regulator and producing voltage, start with the regulator and then look for a short. When looking for a short, it is best if you could disconnect both ends and then check for the short. An Ohm meter will show resistance through the rest of the circuit if only one end is disconnected.

440roadrunner

14.7 is a bit high but not THAT high

"Normal" charging voltage with regulator warm (they are temp compensated is 13.8 -- 14.2, and not below 13.5, and not above 14.5

14.7 is a long long way from causing any sort of damage, and certainly IS NOT going to "heat up" wiring.

TheSkycrane

With my two wires disconnected the engine runs the same, runs the same as what I said earlier WOT, won't idle. With the wires disconnected I lose the screaming sound. NOT MY BELT. I agree with boatman, I think its in my ignition circuit as you have described. And the engine has run fine since rebuild up until my alt started acting up. In doing my own research through other forums and this one It seems easy enough to isolate Im thinking either that or VR. But with that swap to a four pin type ignition I eliminated that. Im out of town on business, left on friday. Im going to check resistance and verify wiring and update when I get back.

RacerHog

I would agree... If theirs a short somewhere. That would make it charge like hell..
But cents the battery does not go dead all the time When sitting. I would say a short "If thats whats up" is going to be somewhere on the Switched side.

440roadrunner

Ignition system RARELY causes poor idle problems unless timing related

TheSkycrane

ok so Timing is good, and here is what I found. I got a new alt, new coil because the ohm was a bit uncomfortable for me. and a new voltage regulator as that is what i determined to be the culprit. with ALL the wires off the alt the car started, ran, warmed up and would now idle. BUT, my voltage regulator has a green wire on one side that goes to the alt, the other side has a blue wire with a white stripe and a dark blue wire, i unplugged these two wires because my new voltage regulator was smoking. with this side off, the car still starts and idles like before. I have observed the following:

Battery has 12v (even when running)
Coil has 11.6 volts and 6.5 volts
Resistor has 11.6 volts coming out of it

So why was my VR smoking? could it still be in that fuseable link or starter relay? Ignition switch has already been replaced, so that would leave ammeter?

A second question my resistor has two wires coming out of the right side of it when looking at it bolted to the firewall, my voltage regulator has two wires coming out of the right side when looked at from the right side and bolted to the firewall. My wiring diagram for a 1967 coronet shows only one wire.

440roadrunner

The voltages you posted means the charging system is NOT working

"Smoke" is NEVER a good thing. No idea why, you need to find out. "What" are you using for a diagram? That we we all know what "we" are looking at.

Suggestion:

Download the Mopar factory service manual here:

http://www.mymopar.com/index.php?pid=31

Da linky

http://www.mymopar.com/downloads/ser...ice_Manual.zip

That way we all know what we are looking at. Now some of these diagrams don't exactly show PHYSICAL wire layout so much as ELECTRICAL layout

That is, here is what you have. The "dark blue" is almost universal in Mopar speak for many years as "IGN 1" "switched ignition" or "ignition run" depending on the slang of the day

THIS BLUE comes FROM the ign switch and is hot ONLY in the "run" position. On your 67 it feeds warning lamps in the dash, power to the cluster for things like gauges.............

and goes through the bulkhead connector................

and supplies the ignition system and voltage regulator power. It is likely that the two wires at the "blue" on the regulator are simply used as a junction point going off to the ignition system
IT IS IMPORTANT to understand that this wire IS NOT FUSED in any way............

except for the main fuse link, which is no protection at all.

IF YOU encounter a problem which causes a SHORT on this blue wire, YOU WILL SMOKE the harness and do damage.

Your new VR might be defective. The new alternator might be defective.

SIMPLY the blue IGN wire feeds the regulator, which MUST MUST be grounded. The VR feeds power out the green to the alternator FIELD, and to ground.

IF YOU happened to get a slipshod ....."rebuilt"..... it's possible that you got one with a GROUNDED field connector

HOW TO TELL?

Easy. Get yourself a multimeter which can measure 10 or 20 amps. HOOK a universal fuse holder in series with the meter to protect it

WHY? Because a meter in "amps" mode IS A dead short!!! IF you have a problem here, you could "SMOKE" the meter as well!!! Many cheaper meters are not!!! protected!!! and even if they are (Fluke, etc) usually the ammeter circuit fuse is 5 bucks a pop

================================================== =====================

SO loosen your alternator drive belt so you can hand turn the pulley

Set the meter up to read 10A or 20A or the largest current scale

HOOK one probe of the meter to the field terminal of your alternator. The green wire of course should be disconnected.

Hook the other meter probe to your universal fuse holder. You want say, a 5A fuse in there

Come out the other fuse lead and hook this to the battery

Now slowly turn the pulley by hand. This is simply to move the brushes / slip rings and "average" out contact. Read the current the meter shows

THIS procedure is IN the factory service manuals. Depending on "what" you have for an alternator, you should get a reading somewhere between 4 and 6 amps.
================================================== ==================

WHAT does all the above show? It shows the field is not shorted and drawing excess current.

Next, examine the green wire carefully. Is it melted, touching the engine block, bare anywhere?

Disconnect the green from the alternator and the VR. now you have a wire that is completely isolated. Check either end "to ground" for continuity. It should be "open" or infinity. WIGGLE the wire around. It should not show a short.

Now move to your dark blue. With the VR disconnected (because it is suspect) the dark blue should show SAME AS battery voltage with the key in the "run" position. It should NOT be getting warm or "smoking."

IS all this OK?

If so, BYPASS the VR temporarily by doing the following test:

Hook everything up "normal" EXCEPT the VR. LEAVE the green and blue unhooked from the VR. HOOK your ammeter---same setup as you did with the field draw test, to the green and the blue wire.

Turn your key to "run" and turn the alternator. You should get the same reading as the earlier test

THIS SHOWS that the wiring and the alternator field are complete and working. If this all looks good,

REPLACE THE VOLTAGE REGULATOR