Slant 6 No Spark

-
M

Montana Y

Member
Joined
Mar 21, 2018
Messages
18
Reaction score
2
Location
New Bedford, MA, USA
While driving my 68 dart one day it suddenly died. There is no spark whatsoever. for the month previous the Amperage Meter had been pegged, so I fear I burned something out. I Found the voltage regulator had welded itself together so I changed that but still nothing. The ignition control module was new, as was the coil. Could i have damaged them? could it also be something in the distributor? Any help would be greatly appreciated.
 
Yes. Good lord why did you drive it that way for more than 2 minutes? Surprised the battery doesn't smell bad and puking acid all over, and surprised you didn't burn up a few things, like the radio, headlights......

Likely did not damage the dist. By the way most any parts store replacement VR you will find is a solid state replacement for the old "welded contacts."
 
The amp gauge was pegged for a month? We caint help this guy.
 
67Dart273 said:
Yes. Good lord why did you drive it that way for more than 2 minutes? Surprised the battery doesn't smell bad and puking acid all over, and surprised you didn't burn up a few things, like the radio, headlights......

Likely did not damage the dist. By the way most any parts store replacement VR you will find is a solid state replacement for the old "welded contacts."
Click to expand...

Yeah, as I mentioned I already changed the VR. Nothing smoked, burned, or ever showed any sign of damage. Plus all of my gauges aren't really reliable, which is why I ignored them.
 
Montana Y said:
Not helping, dude.
Click to expand...
Maybe. But hopefully he got your attention.
When the ammeter is pegged in either direction there is problem! A big problem!

Knowing its a 68 with an ECU and a points type regulator suggests it may have been miswired when the ECU was added.
Could also be a battery problem - internal short - or something else that was full fielding the alternator for long periods of time.

Lets go back to why a pegged ammeter is big problem.
If you can picture current flowing like a water, a few amps is like a creek. In contrast 40 amps (pegged) is like fast moving river. But the wiring is only the size of a stream bed. You can imagine what destruction happens when a river like torrent flows through a stream bed.

The ammeter shows whether current is flowing in or out of the battery. Unless its been miswired, that's all it shows. In other words, it shows the amount of Battery Discharging or Battery Charging.
 
RustyRatRod said:
Fair enough. Maybe this will help.

MoPar Instrument Cluster Regulator Update

If mine ever malfunctions, I plan on doing something similar.
Click to expand...
confused-gif.gif


The IVR isn't related to the ammeter.
The ammeter is a metal bar and a magneticly sensitive needle mechanism.
The current flowing through the bar moves the needle.
Diagram and explanation on this page
Electrical Fundamentals (Session 220) from the Master Technician's Service Conference
 
Last edited:
I should point out too that the motor turns over and is getting fuel. Also the ballast resistor is new so it's not that either. I did convert the car over to electronic ignition from points when i swapped engines. (old slant 6 was blown, so I put a super slant 6 in). I checked the wiring several times over when i did it, so I know it's correct (I was very paranoid about getting it wrong). And it ran fine for about 6-8 months after the conversion.
 
Montana Y said:
I'll take a look at this. Thank you.
Click to expand...
Sorry. I like Rusty, but that's off track. If the other gages are unreliable, then yes, maybe the IVR is at fault. But it could be other things too.
 
Mattax said:
Sorry. I like Rusty, but that's off track. If the other gages are unreliable, then yes, maybe the IVR is at fault. But it could be other things too.
Click to expand...

I was not posting that to solve his problem at hand. Just so that he could upgrade later on if he wanted to. I have grown tired of online diagnosis. Too many times there's not enough info and there's always too many opinions.....usually from people who've never turned a wrench.
 
Montana Y said:
I should point out too that the motor turns over and is getting fuel. Also the ballast resistor is new so it's not that either. I did convert the car over to electronic ignition from points when i swapped engines. (old slant 6 was blown, so I put a super slant 6 in). I checked the wiring several times over when i did it, so I know it's correct (I was very paranoid about getting it wrong). And it ran fine for about 6-8 months after the conversion.
Click to expand...
Well something hasn't been correct for a month. That's what you need to figure out.
Start with the battery, then check the wiring.
If the problem is (was) strictly the regulator point sticking, then the voltage would follow the rpm. On the ammeter this would have shown as moderate charge at idle, and only pegged charge while driving. That's because (a) the maximum alternator output at idle is usually less than 40 amps. (b) at lower voltage a battery will take less charging current. You've seen that with a light bulb relationship in light bulbs. When voltage drops they draw less current and grow dimmer.
 
The ballast isn't good "just because" it's new. Have you actually checked it?
 
Mattax said:
Well something hasn't been correct for a month. That's what you need to figure out.
Start with the battery, then check the wiring.
If the problem is (was) strictly the regulator point sticking, then the voltage would follow the rpm. On the ammeter this would have shown as moderate charge at idle, and only pegged charge while driving. That's because (a) the maximum alternator output at idle is usually less than 40 amps. (b) at lower voltage a battery will take less charging current. You've seen that with a light bulb relationship in light bulbs. When voltage drops they draw less current and grow dimmer.
Click to expand...

This sounds about right. as you said it only pegged when driving. at idle it was at moderate charge.
 
Right. Back to the first question you asked. Yes the coil and or the ECU could have been damaged whenever the VR points stuck. Possibly the ballast resistor. With an electronic ECU the resistor is needed for power during start.
Measure the coil primary resistance. Should be around 1.5 to 2 Ohms. If its open, the the coil is burned out.
Measure the ballast resistor (cause its easy). Should be .5 ohms or a little more is OK.
ECU I can't think of a quick and easy cheack off the top of my head. Eliminate the other possibilites first. Then if not, try another ECU.
 
Mattax said:
Right. Back to the first question you asked. Yes the coil and or the ECU could have been damaged whenever the VR points stuck. Possibly the ballast resistor. With an electronic ECU the resistor is needed for power during start.
Measure the coil primary resistance. Should be around 1.5 to 2 Ohms. If its open, the the coil is burned out.
Measure the ballast resistor (cause its easy). Should be .5 ohms or a little more is OK.
ECU I can't think of a quick and easy cheack off the top of my head. Eliminate the other possibilites first. Then if not, try another ECU.
Click to expand...

Thank you so much. I'll check all of this. I'll replace any of the bad components and if both the coil and Ballast resistor are fine then I'll change out the ECU. Again thank you. this is just the info i needed.
 
Montana Y said:
This sounds about right. as you said it only pegged when driving. at idle it was at moderate charge.
Click to expand...
OK. Getting closer.

Since its turning over, the battery's not dead.
But at some point check the battery condition and charge level.
If its a traditional wet cell battery, check the acid level. Should cover the lead plates. If not add distilled water.
If its a sealed battery obviously can't do that.
 
Montana Y said:
I should point out too that the motor turns over and is getting fuel. Also the ballast resistor is new so it's not that either. I did convert the car over to electronic ignition from points when i swapped engines. (old slant 6 was blown, so I put a super slant 6 in). I checked the wiring several times over when i did it, so I know it's correct (I was very paranoid about getting it wrong). And it ran fine for about 6-8 months after the conversion.
Click to expand...

Some things. You need some jumper "alligator clip" wires, a 12V test lamp, a multimeter.

1....Turn the key to run, measure the coil + voltage. It should be somewhere between 8--10V Much lower something is wrong, and if it reads "same as battery" something is wrong.

2....Crank the engine, read the meter while cranking. Voltage should be "same as battery" and at least 10.5V

3....With key in "run" separate the 2 wire distributor pickup connector. Rig a test gap at the coil HV wire. Take the part of the connector that is the engine bay harness end and tap the exposed terminal against ground. Should make a single snap blue spark each time.

4....Check the ground on the ignition box "ECU." It MUST be grounded (as must the VR)
 
You must log in or register to reply here.
-

Back
Top