Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

[Kern Dog]

No screw. Neither of these cars have screws holding the ECM plug in place.

The red one is the only car that has this issue. The car in the foreground (Jigsaw) has never failed to start.
Just another summary for those that don't care to read every post:
I did the electronic conversion in 2001 before I swapped from the stock 318 to the first 440. It was several years before the no spark issue reared it's ugly head. It would always occur here at home but one time it was at an indoor car show at the time we were leaving. Nobody had any spare parts, no jumper wires, no tools. I just wiggled wires until it finally started.
Over the years, the issue would crop up at the most inopportune times. TWICE it happened during a fresh/first fire of a engine rebuild and of course, both times it was with flat tappet cams where instant starts are crucial to cam and lifter life. Other times it would happen at home. I have changed every ignition part at one time or another...Distributor, coil, ballast resistor, multiple ECMs, I've cleaned the bulkhead terminals, I've tried different ignition switches...once it starts, I figure that I fixed it but then is craps out again another time later.
Of the 6 times I've taken road trips of over 900 miles, it never failed on me. It always started every time I drove it around town too, except for the one time a few months ago. Seriously....this is random and weird. Every time but once that it failed has been here at home. Because of that, I've often tested parts on other cars. I did follow through with the booklet that I got from Halifax Hops. I got voltage where I am supposed to at the ECM plug:

Autopsy that blue box - see what's under that transistor cover?

Goo and electronics... Probably popped a capacitor.

I do sometimes save parts that failed to inspect them later. I may dig in after I get this fixed.
I am tired of the anxiety of this. I love the car but can't trust it to always start. The ignition portion of the harness was bought new in 2013 to fix this very issue that also randomly happened before.

 

[68 Sport Satellite]

KD - just to cover all bases in a one shot review, would you care to make a 4 column table with both cars in the far right columns and the far left column for components and date installed so we know how new they are, then for each row list each component so you can see at a glance each component that is the same or new for each car and which components are not. I know this is in your head and you've tried everything, but maybe listing it all out in one table will present an ah-ha moment.

Now sans table - going off the wire jiggle method and possible ECU reliance on voltage, if your battery is already low or problematic, then any loose connections or increased resistance will make things much worse. Have you ever swapped batteries from Jigsaw to Ginger? Remember that Ginger's battery is in the trunk and Jigsaw's is under hood, correct? Another thing that comes to mind - in the table list you should also include all electronic accessories - for example, does Ginger have A/C and Jigsaw does not? Does Ginger have a radio and Jigsaw does not? I had an issue one time in my 67 in high school where I had a radio wiring issue causing a parasitic draw. My buddy helped me figure it out when we were installing a car alarm. Another time on that same car, one of my door jam switches that turns on the interior lighting when you open the door was sticky.

Do the table - even if you think it's a waste of time. You're retired anyway. DO IT!

 

[padam]

Did you do anything with the bulkhead connector?

 

[Don Frelier]

I did notice this…
Here is a new harness for a conversion:

View attachment 1751984

View attachment 1751985

The contacts all look pretty, huh?
Now look at the one in the car.
View attachment 1751987

View attachment 1751988

The terminals are grungy but are they bad enough to be an issue?

I tried two different spare coils and still no spark.
The testing methods of the booklet are not enough!

The terminal condition shown here could definitely be the culprit.
If the connection is comprimised the problem would likely be that signal from the reluctor and pickup coil is attenuated (knocked down).
It's a low amplitude, low current pulse generated by the reluctor moving past the pickup coil.
The combination of heat cycling and a bit of corrosion could be enough (occassionally) to reduce it enough where the ECU will not fire.
So the ECU is not neccessarily bad is just doesn't see anything to amplify.

Now the act of unplugging and plugging in a different one, notice I didn't say new, is enough to wipe the contacts and restore the connection.
You perhaps might get the same results without changing the ECU, simply plugging and unplugging it.
But either way the corrosion is still there and later spreads similar to rust.

Marking the ECU's was a good idea. But since you really were'nt 100% sure of the problem it would have been wise to put a removable sticker on them or at least mark them on the back.

But I've seen carpenters make mistakes before.
My Dad was a carpenter.

 

[hunt2elk]

Sure sounds like either a bad/compromised wire terminal end or crimp connection. I had a 1 year old M&H harness with 2 loose wire crimps. They looked fine, but weren't. Intermittent issues just like you are having and was a bugger to find them.

 

[Bee1971]

"Now the act of unplugging and plugging in a different one, notice I didn't say new, is enough to wipe the contacts and restore the connection.
You perhaps might get the same results without changing the ECU, simply plugging and unplugging it.
But either way the corrosion is still there and later spreads similar to rust."

Same with the bulkhead connectors

Same with the ballast resistor - Replacing the ballast resistor fixed the problem UNTIL - The ballast resistor wasn’t the problem to begin with , all that was done was the wires or connectors got moved and made a contact , same with the bulkhead


I always emphasize when checking wiring with a volt meter / ohm meter , don’t just check the end of the connector , check where the wire enters the terminal also

 

[Bee1971]

Clean

 

[Bee1971]

Autopsy that blue box - see what's under that transistor cover?

CHINA

 

[Cranky]

Points. Problem solved.
40k miles and never left me stranded.

The only time that I thought my 66 Belevdere might strand me was when the points rubbing block was wearing down and the gap was getting really close. One night on the way home from work, it died 1/2 way home. Didn't have any tools with me so I let it cold down some and sure enough, it started back up so I just drove it home easily instead of hammering on it like I usually did. It ran the rest of the way.

 

[Cranky]

Just another summary for those that don't care to read every post:

Well dang it Greg, you stay up most of the night posting and trying to keep up with 'all' of it isn't exactly easy. Just because you don't sleep much doesn't mean we don't. Not 'everyone' is 'like' you are!!!

 

[toolmanmike]

I had a no crank condition on my 69 Bee. Pop the hood and wiggle the wires at the bulkhead and it would crank over and start right up. The 12 volt feed to the dash goes through the bulkhead and although it's more amperage, M Mopar ran it through the same size/gauge of connector. The connector was black and the plastic housing was melted. (both sides) I just drilled through the cavity and fed the dash with some 10 gauge wire. I didn't actually fix it properly but I made it work.

 

[Cranky]

But I've seen carpenters make mistakes before.
My Dad was a carpenter.

My dad was a carpenter too and so was I.....worked with him for a few years starting at 14 then ended up working for him once out of high school.

 

[pnora]

I have had many distributor pick up units fail.

 

[RJRENTON]

Goo and electronics... Probably popped a capacitor.

PROBABLY......means what....there are only two capacitors used in the dwell timing network...which one??. What about the diodes and pilot transistors.....maybe the paint color is incorrect....probably. The "goo" keeps the uneducated from performing "surgery" on something they know nothing about.....
BOB RENTON

 

[RJRENTON]

Maybe they really aren't bad units!

But maybe they are......HOW DO YOU TEST THEM?? By substitution? Or perhaps you are just a hoarder and just likes to accumulate stuff...good or bad....just to say: "aren't electronics wonderful??" .......
BOB RENTON

 

[padam]

PROBABLY......means what....there are only two capacitors used in the dwell timing network...which one??. What about the diodes and pilot transistors.....maybe the paint color is incorrect....probably. The "goo" keeps the uneducated from performing "surgery" on something they know nothing about.....
BOB RENTON

That’s really what the goo is for?

I demand evidence.

 

[68 Sport Satellite]

The terminal condition shown here could definitely be the culprit.
If the connection is comprimised the problem would likely be that signal from the reluctor and pickup coil is attenuated (knocked down).
It's a low amplitude, low current pulse generated by the reluctor moving past the pickup coil.
The combination of heat cycling and a bit of corrosion could be enough (occassionally) to reduce it enough where the ECU will not fire.
So the ECU is not neccessarily bad is just doesn't see anything to amplify.

Now the act of unplugging and plugging in a different one, notice I didn't say new, is enough to wipe the contacts and restore the connection.
You perhaps might get the same results without changing the ECU, simply plugging and unplugging it.
But either way the corrosion is still there and later spreads similar to rust.

Marking the ECU's was a good idea. But since you really were'nt 100% sure of the problem it would have been wise to put a removable sticker on them or at least mark them on the back.

But I've seen carpenters make mistakes before.
My Dad was a carpenter.

this makes me think of what happened to me many times back in the 80's until my dad clued me in...was running points distributor, during foggy mornings sometimes I'd get no spark. Dad explained condensation got inside the distributor cap. Spray some WD40 inside the cap to get rid of the moisture and bammo - engine starts. Anything where moisture can get in from the air could in theory contribute to this issue.

 

[padam]

I just fixed a problem on my wife’s van. PO used it for his residential electrical business and was a volunteer fireman, so a lot of electrical ad ons.

The problem was headlights were dim.
To make a long story short, I checked voltage several places along the circuit and it was good until the actual female headlight plug, which gave intermittent low voltage.

The plug and headlight prongs were both corroded. I replaced the plug and polished the prongs. Voltage was good and headlights are now brighter.

 

[RemCharger]

this makes me think of what happened to me many times back in the 80's until my dad clued me in...was running points distributor, during foggy mornings sometimes I'd get no spark. Dad explained condensation got inside the distributor cap. Spray some WD40 inside the cap to get rid of the moisture and bammo - engine starts. Anything where moisture can get in from the air could in theory contribute to this issue.

Many years ago I sprayed wd40 in my distributor to loosen up the weights and went to start it, bammo- blew the cap right off

 

[MWbirdLOVER70]

Many years ago I sprayed wd40 in my distributor to loosen up the weights and went to start it, bammo- blew the cap right off

Had a kid in tech school automotive with a GM that had points sight window to set points and sprayed starting fluid in there to start car. Talk about kaboom