New Ignition coil, rotor, and distributor cap, but no spark. Need help.

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nephlyte

nephlyte

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I was driving back to school the other day and out of nowhere my engine turned off. It was running fine one second, then it turned off the next second and hasn't restarted.

My first thought was the ignition coil, then as long as i was there, i replaced the rotor and distributor cap, cause i should've done that anyway last week. The ignition coil is getting power, but there is still no spark going on.

I'm now at a loss. What else should i test with my test light to see whats going on? All the plug wires are good?

What could be the failure? Also, i need to get to san antonio by sunday and i can't even fix my car.

Edit: It has a mopar electronic ignition on the slant 6. So, no points to worry about.
 
Your signature line says you have a 66 so I am assuming you still have points. Check to make sure the points are still opening and closing as the engine cranks. The adjustment screw could have come loose and \6's have been known to eat distributor drive gears.

If the car has been converted to electronic ignition it could be either the pick-up in the distributor or the ecu.
 
power at the coil in run and start position? 12 volts to blue/ylw wire in ecu harness? blk/ylw to coil - ? ecu has good ground? ground strap on engine?
 
redfastback said:
power at the coil in run and start position? 12 volts to blue/ylw wire in ecu harness? blk/ylw to coil - ? ecu has good ground? ground strap on engine?
Click to expand...

2nd vote for ballast resistor, prolly a $3.00 fix.
 
redfastback said:
power at the coil in run and start position? 12 volts to blue/ylw wire in ecu harness? blk/ylw to coil - ? ecu has good ground? ground strap on engine?
Click to expand...

Alright, i'm gonna go check this now. There is power to the Plus side of the coil in start and run position. I'll go check the blue and yellow wireon the ecu harness.

The blk/ylw wire is hooked up to the negative side of the coil, so thats good. That is just a ground, right? What color is the ground on the ECU?

BTW, thanks for the help with wires.

Also, there are no points. This has electronic ignition. The ballast resistor is part of a points system, right? If not, is this the little gizmo under the distributor cap? Could that little thing have gone out?

Sorry, i'm not versed in all the electronic lingo. This is the first time i've had to do any electronic fixing on this car.
 
if it was a ballast resistor, it would start and want to run, but as soon as you let go of the key to run position, it will die. are you getting spark out of the coil? the ground on an ecu is the box mounting.
 
redfastback said:
if it was a ballast resistor, it would start and want to run, but as soon as you let go of the key to run position, it will die. are you getting spark out of the coil? the ground on an ecu is the box mounting.
Click to expand...
Not necessarily, I had one fail that would sometimes start and sometime just crank, turned out to just be on the verge of total rust out in back of resistor.
 
Does'nt the coil pickup tell the coil when to fire anyhow? I will restate my previous conclusion, prolly either the coil pickup, ignition box, or ballast resistor. Bet that makes it easier:violent2:
 
redfastback said:
power at the coil in run and start position? 12 volts to blue/ylw wire in ecu harness? blk/ylw to coil - ? ecu has good ground? ground strap on engine?
Click to expand...

Power to coil in run and start, check.
12 volts to blue/ylw wire in ECU harness, check
Blk/ylw wire to coil -, check
ECU has a good ground, check
Ground strap on engine, check.

I found the ballast resistor, I'll go grab a new one of these. Or is there a way to test it?

Also, i'd hate it to be the ignition box, those are expensive. But do those just die in an instant?

BTW, there is absolutely no spark. The engine doesn't even try to run.
 
yes it can happen. get a regular one at napa or similar. its worth it to have backup if anything.
 
New ballast resistor. No luck.

I suppose it is the ECU. Is there anything else?

How much do those run?
 
nephlyte said:
Power to coil in run and start, check.
12 volts to blue/ylw wire in ECU harness, check
Blk/ylw wire to coil -, check
ECU has a good ground, check
Ground strap on engine, check.

I found the ballast resistor, I'll go grab a new one of these. Or is there a way to test it?

Also, i'd hate it to be the ignition box, those are expensive. But do those just die in an instant?

BTW, there is absolutely no spark. The engine doesn't even try to run.
Click to expand...

I had the exact same thing happen to me and after exhaustive ground/wire/coil/ballast/ all the usual suspects came up a no go it ended up being the pickup in the distributor.

What ECU box are you running OEM style or MSD? If it's an OEM orange or blue box, just find a used one and test it...
 
Beatnik said:
I had the exact same thing happen to me and after exhaustive ground/wire/coil/ballast/ all the usual suspects came up a no go it ended up being the pickup in the distributor.

What ECU box are you running OEM style or MSD? If it's an OEM orange or blue box, just find a used one and test it...
Click to expand...

Ahh, does that pick up say when to spark? Perhaps i should go get one of those? I thought that only controlled the spark advance.

ECU is a black box with a mopar stamp on it. The PO installed it(who knows when), because obviously a 66 valiant would've had points otherwise.

You said to test it. How do you test an ECU? I could go ahead and test my own and see if its good.

Well, on the bright side of all of this, i'm totally going to have a brand new ignition system.:laughing:
 
i just replaced the ecu in my pickup. it would start and run fine and then just die. few minutes later it would be fine again. get a new one and keep a spare in the glovebox. they do "just go out", its pretty common. make sure that it has a good ground. scrape the paint off where it bolts to the body just to make sure.
one other thing you might check is the gap at the pickup in the distributor. there should be a gap just like points. im not sure what the gap is but someone else will.
 
sweatybetty said:
i just replaced the ecu in my pickup. it would start and run fine and then just die. few minutes later it would be fine again. get a new one and keep a spare in the glovebox. they do "just go out", its pretty common. make sure that it has a good ground. scrape the paint off where it bolts to the body just to make sure.
one other thing you might check is the gap at the pickup in the distributor. there should be a gap just like points. im not sure what the gap is but someone else will.
Click to expand...

The reluctor gap is .008" according to the factory manuals, and they emphasize using a non-magnetic feeler gauge. I used a standard business card out of my wallet. The cardboard IS non magnetic, and it miked out at.0078. (I just had to check with my new digital micrometer) Must have been close enough, it's been running that way for three years. Make sure you tighten the hold down screw.
 
Thanks everyone. It was the ignitor. Luckily a local store had it in stock.

Bonus: I made it to school in time after all.

Bonus 2: I have a bunch of new electrical stuff.
 
nephlyte said:
Thanks everyone. It was the ignitor. Luckily a local store had it in stock.

Bonus: I made it to school in time after all.

Bonus 2: I have a bunch of new electrical stuff.
Click to expand...

I'm guessing what you replaced was the pickup coil inside the distributor, since "Ignitor" is the Pertronix name for their electronic unit that fits inside the distributor. Glad you made it back to school! Study hard and one day you will be able to afford to pay shop rates to have clowns throw parts at problems 'til they get lucky and find what a little simple troubleshooting would have led them to if they knew how!

OOPS, I think I just had a FEELING moment there - - -'scuse me..... and no offense intended to the few, the proud, the mechanics that DO know how to troubleshoot!

Well, that cool new electrical stuff could be the beginnings of your next project car, if you have the wrench sickness like some of us do!

BC
 
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