Ignition problems 440

[thethee]

I don't understand what's happening.

Drove the car to an empty lot (~10 minutes) so I could make my adjustments. Parked with running engine to check vacuum at vacuum advance line, but before I could attach the gauge engine died without warning. Attached the gauge to the carb and went for hot start. Started with just a touching the key.

Idled nice, vacuum advance line had NO vacuum at idle. Raised rpm to check and then it did have some vacuum. Then without warning it died again...

Attached my multimeter to the coil for next time it dies to see if coil loses power. It didn't, it idled smooth for about 20 minutes, all the while coil had steady 8.8 V.

Turned off the engine and by now it should be proper "hot" start. Started with just a flick of the switch. Final check, reattach vacuum line to distributor, single crank and it started.

Going to back down initial to 16 degrees and call it a day.

 

[thethee]

Drove it home without it dying.

I forgot to check how much mechanical advance is in the distributor, but I did check vacuum advance. Didn't have a handheld vacuum pump so just stuck on a hose and sucked on it till it didn't advance any further. Dial back timing light gave 46 degrees, so maximum vacuum advance is 30 degrees. Don't know if I did that right though.

About it dying, for now I'll just spend a day cleaning electrical connectors first, couldn't hurt.

 

[Big_John]

Possibly if the 5-ohm resistor (and possibly both resistors) is failing in a high-resistance condition, you may get the case where the engine won't fire in START because the combined resistance is too high so the voltage is too low going to pin-3, but will fire in RUN.

That's as good an explanation as I've ever heard.

I never really took the time to figure out the circuit, just knew that was how the failure happened and the cure. I think one of the first things I did when I bought my 300 and saw the dual resistor (some previous owner conversion) was pull the plug on the ECU and when I saw it only had 4 pins, the wiring got changed.

 

[CBODY67]

But still, this has me wondering. When I looked online for timing settings I found a lot of threads on F_BO forums and moparts and such that mention something along the lines of "mopar BB like a lot of advance" and "needs more timing with todays bad gas" and a lot of those mentioned running 17-19 degrees advance. Or would that be okay for non-stock 440's and too much for completely stock?

KEY thing about "lots of advance" would be . . . "In relation to what engine?" Also consider that the total advance of 38-40 degrees BTDC (initial + total mechanical in the distributor) is pretty much like a small block Chevy, but way too much for a Chevy W-engine 348-409.

That hot restart issue was quite prevalent on many small boock Chevy "hot rodded" motors, too. Which is why Chevy seemed to come out with several versions of starter heat shields, over the years. One "fix" for Chevy-chassis motor homes was to wire-in a Ford starter relay!

I'm not sure why you feel you need so much initial advance, fwiw. On our '66 Newport 2bbl 383, the spec initial timing was 12.5 degrees BTDC, but it had no issues with 15 degrees BTDC, but never went past that as it put the total right at 40 degrees BTDC. ALWAYS started just as it should, hot or cold. Other than the normal hot-soak slightly extended crank time.

Just some thoughts,
CBODY67

 

[Gerald Morris]

This is interesting.

I disconnected the starter so I could check the ignition without having to crank the engine.
....
who'd have thought a running engine could be frustrating?

Can a ballast resistor be good cold and bad when hot?

YES! Had an electron ignition on my 440 '66 NYer back in 04-05. Damn thing acted like this when hot. Replaced the dual ballast resistor when I saw how the element i the low resistance (starting) was broken, though still passing current when cold. When it got HOT (which was how I saw the problem) the damned element would push out a little, disconnecting its 2 portions. I got home that night by bypassing the resistor, then getting a replacement. The big high zoot! coil also got dicey, though the main seal did worse before I got to that monstrous Accel.

Replace your ballast resistor.

 

[thethee]

I'm not sure why you feel you need so much initial advance, fwiw. On our '66 Newport 2bbl 383, the spec initial timing was 12.5 degrees BTDC, but it had no issues with 15 degrees BTDC, but never went past that as it put the total right at 40 degrees BTDC. ALWAYS started just as it should, hot or cold. Other than the normal hot-soak slightly extended crank time.

Just some thoughts,
CBODY67

I must admit, it wasn't so much that I felt the need but more like a "let's see what this does" kind of thing. With more initial it idled at higher RPM so I figured it ran better with more initial and could lean out the carb a little. As initial was still below the numbers I came across online I didn't think much of it to be honest. Now I know that what I should've done, and absolutely will do, is look at the amount of total timing (initial + mechanical) first and make sure it stays below 40 degrees. Lesson learned, thanks guys!

Will report back with my findings.

 

[thethee]

Decided to bench test my ballast resistor this evening. Put it in a bowl and hooked up my multimeter. While watching the reading on the meter I submerged it in hot water, kind of like testing a thermostat. For both sides of the ballast resistor it varied slightly but never more than one or two tenths of ohms.

Low side settled around 1.3 ohms and high side settled around 4.6 ohms. Although not quite within spec this little test leads me to believe my ballast resistor is okay. Do you agree?

 

[65sporty]

Decided to bench test my ballast resistor this evening. Put it in a bowl and hooked up my multimeter. While watching the reading on the meter I submerged it in hot water, kind of like testing a thermostat. For both sides of the ballast resistor it varied slightly but never more than one or two tenths of ohms.

Low side settled around 1.3 ohms and high side settled around 4.6 ohms. Although not quite within spec this little test leads me to believe my ballast resistor is okay. Do you agree?

It's warm from the water, but is it the same as the resistor getting warm from a electrical load?

 

[Big_John]

It's warm from the water, but is it the same as the resistor getting warm from a electrical load?

It's not.

 

[Big_John]

Decided to bench test my ballast resistor this evening. Put it in a bowl and hooked up my multimeter. While watching the reading on the meter I submerged it in hot water, kind of like testing a thermostat. For both sides of the ballast resistor it varied slightly but never more than one or two tenths of ohms.

Low side settled around 1.3 ohms and high side settled around 4.6 ohms. Although not quite within spec this little test leads me to believe my ballast resistor is okay. Do you agree?

Warming it up in water is not the same as the heat generated by the electrical current running through the resistor.

 

[65sporty]

Warming it up in water is not the same as the heat generated by the electrical current running through the resistor.

That was my thought, I figured you would know.

 

[Big_John]

FWIW, I just remembered reading of a problem where the ECU wasn't grounded well. It would get hot and the ECU would shut off until it all cooled down. Hard problem to diagnose.

It's a good preventative check to make sure the ECU is grounded well anyway, but this is a little more incentive.

 

[Big_John]

That was my thought, I figured you would know.

If you think about it, an ignition coil can draw 5 or 6 amps and that would give you around ~80 watts and that would make that resistor wire fairly hot. You have some outside temperature from the engine (which can be duplicated with the water) that adds to it. I can't tell you what those ballast resistors are spec'd to, but I wouldn't be surprised if they were spec'd to 200 degrees C which is 392 degrees F. The ceramic gets pretty hot, and that is dissipating heat from the wire coil inside which gets a lot hotter.

If the BR was starting to fail, and the resistance was going up, the heat would go up too... which would increase the resistance... which would increase the heat... and on and on.

 

[thethee]

Warming it up in water is not the same as the heat generated by the electrical current running through the resistor.

Oh okay, I thought since the water was from the kettle and near boiling point (100 C, 212 F) it would give some idea, but actually it doesn't really matter since I'll be getting a new BR anyway. Looking at the ignition diagram and symptoms all point to it being the cause.

 

[thethee]

FWIW, I just remembered reading of a problem where the ECU wasn't grounded well. It would get hot and the ECU would shut off until it all cooled down. Hard problem to diagnose.

It's a good preventative check to make sure the ECU is grounded well anyway, but this is a little more incentive.

ECU is grounded through it's mounting bolts right? Will check those as well.

 

[Big_John]

ECU is grounded through it's mounting bolts right? Will check those as well.

It is, but paint and rust can always give you issues.

I'm not pointing to this as the problem, just noting that others have experienced this issue and it's always a good thing to check.

 

[thethee]

Okay guys, new symptoms.

Currently experiencing a no start condition. Normally with cold engine voltage at the coil was around 7V with key in "run" and around 9V with key in "start". Right now voltage at the coil is around 12V with key in "run" and around 9V in "start" position. Also, it is not firing when I release the key.

But then I disconnected the ballast resistor and this is what I found:

Key is in "run" position. Multimeter is measuring "start" side of the BR. This shouldn't have power right?

 

[thethee]

After letting it sit for a couple of minutes engine started like normal again. However, voltage at the BR feed was dropping intermittently. Ignition wire from "run" position on left side of BR was around 13V then down to say 5V for a brief moment and then back up to 13V.

I'm starting to think main problem might be at ignition switch or in wiring from ignition switch..

 

[thethee]

Can I run a jumper wire to BR directly from positive battery terminal to bypass ignition?

 

[Gerald Morris]

Can I run a jumper wire to BR directly from positive battery terminal to bypass ignition?

That sort of "hotwire" job should be used only in emergency situations when you need to start the engine and have nothing else to do it. Make an alligator clip jumper....