Engine died. Now won't start

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Big D

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Was slowing for a stop light the other day and the car died. Pushed it to the side of the road and tried restarting it. Nothing. Waited 20 minutes and tried again. It started then died 5 blocks away. After towing it home and checking for spark, nothing. No spark out of the coil to the distributor. Replaced the ECU with one I already had, nothing. Did notice that the ballast gets really hot with the key in the run position and replaced it with another one I already had, but nothing. '73 Plymouth Duster with a 360. Replaced Accel Superstock coil. The coil has no resistance between pos. and neg. terminals, and has some resistance from the terminal to the tower using the ohm meter. The car had been running very rich and I was checking the run characteristics for timing advance when it died. Made the Ammeter bypass conversion a month back but that was straight forward and hasn't been a problem. Any suggestions or things to check would be appreciated.

David
 
With the key in "run" position, therer should be voltage at the coil "+" terminal. Should be less than battery voltage due to the ballast resistor.

If no voltage there, use a jumper wire from the battery positive to the coil positive. Now see if it starts or at least see if there is spark while cranking.

Check the reluctor gap (under the distributor cap) It should be set at .008"
 
Try a new ECU. They do have a heat related failure issue. Start and die again in a few minutes , there's your sign.
Ballast resistors are supposed to get hot.
 
Big D said:
The coil has no resistance between pos. and neg. terminals,
Click to expand...


Please explain what you mean. "No" resistance could mean zero ohms, or infinity.

"No" could mean that your ohm meter just is not very accurate at low readings, and if it is reading "zero" then the coil may be OK, or may be shorted

If it is "infinity" (as when the leads are not connected to anything) then it is definitely "bad" meaning the primary windings are "open"


Big D said:
has some resistance from the terminal to the tower David
Click to expand...


What means "some?" There should be "some" probably several 10's of K or kilo ohms

You need to do some troubleshooting to narrow it down.

With the key on, as someone said above, there should be some voltage at the coil negative, and probably very low voltage at the coil negative.

You should be able to hook your meter on low AC volts to the distributor connector and crank the engine. The distributor pickup should generate about a 1 volt AC

Also check voltage at the coil positive "when cranking." This should be about the same as battery, IE if the battery is 10.5 when cranking, then you should see close to that at the coil positive.

I'll tell ya, I made the decision to get rid of the Mopar box and go with GM HEI, and so far so good. Stock coil, no resistor, and HEI hooked to an Accel "stock replacement" type dist, which uses a Mopar pickup coil.

I have had some trouble with Mopar breakerless pickups, and a discussion on "another board" with someone who has done a HELL of a lot of tuneups indicates he suspects that pickup coils MAY lose their magnetism -- which would explain otherwise unexplained failure
 
i had the same problem with a ecu some grey box was in car when i got it
thru in the orange box all taken care of
 
69swinger340391 said:
With the key in "run" position, therer should be voltage at the coil "+" terminal. Should be less than battery voltage due to the ballast resistor.

If no voltage there, use a jumper wire from the battery positive to the coil positive. Now see if it starts or at least see if there is spark while cranking.

Check the reluctor gap (under the distributor cap) It should be set at .008"
Click to expand...

There is voltage at the + terminal with the key in the run position, but no spark when I jump the coil from the battery and try to start it. I "eyeballed" the reluctor gap and it's pretty close without touching but I only have steel feelers so my guestimate should be pretty close.
 
Replace the reluctor, I've had them crap out when engine is hot then come back to life after things cool down
 
The negative side of your coil is grounded by the distributor and the ecu and fires the coil when grounded.
If you have power to the coil on + side,disconnet the negative lead completely from the coil and put a temporary wire to it and with the coil wire near metal tap your negative temporary wire to a ground and if the coil should fire.Then the coil is good you need a distributor or ecu.
TXDart
P.S. Of course with the key on.
 
67Dart273 said:
Please explain what you mean. "No" resistance could mean zero ohms, or infinity.

"No" could mean that your ohm meter just is not very accurate at low readings, and if it is reading "zero" then the coil may be OK, or may be shorted

If it is "infinity" (as when the leads are not connected to anything) then it is definitely "bad" meaning the primary windings are "open"





What means "some?" There should be "some" probably several 10's of K or kilo ohms

You need to do some troubleshooting to narrow it down.

With the key on, as someone said above, there should be some voltage at the coil negative, and probably very low voltage at the coil negative.

You should be able to hook your meter on low AC volts to the distributor connector and crank the engine. The distributor pickup should generate about a 1 volt AC

Also check voltage at the coil positive "when cranking." This should be about the same as battery, IE if the battery is 10.5 when cranking, then you should see close to that at the coil positive.

I'll tell ya, I made the decision to get rid of the Mopar box and go with GM HEI, and so far so good. Stock coil, no resistor, and HEI hooked to an Accel "stock replacement" type dist, which uses a Mopar pickup coil.

I have had some trouble with Mopar breakerless pickups, and a discussion on "another board" with someone who has done a HELL of a lot of tuneups indicates he suspects that pickup coils MAY lose their magnetism -- which would explain otherwise unexplained failure
Click to expand...

I mean 0 ohms as "no" resistance. The test of the tower of the coil to a terminal shows some ohms. Not sure how much as my ohm gauge reads less than 1 ohm on the positive side and just over 1 ohm on the negative side. The positive side shows around 6 volts when cranking.
 
TXDart said:
The negative side of your coil is grounded by the distributor and the ecu and fires the coil when grounded.
If you have power to the coil on + side,disconnet the negative lead completely from the coil and put a temporary wire to it and with the coil wire near metal tap your negative temporary wire to a ground and if the coil should fire.Then the coil is good you need a distributor or ecu.
TXDart
P.S. Of course with the key on.
Click to expand...

Did this - Sparked as I tapped the temporary wire to ground on each tap.
 
demon seed said:
Replace the reluctor, I've had them crap out when engine is hot then come back to life after things cool down
Click to expand...

Demon Seed - That reluctor is a cast steel unit - It would be the very last thing I would replace as it seems to be the item least prone to problems. Are you referring to the pickup? That whole distributor is a cheap new unit but I suppose it could be bad already.

D
 
Big D said:
Demon Seed - That reluctor is a cast steel unit - It would be the very last thing I would replace as it seems to be the item least prone to problems. Are you referring to the pickup? That whole distributor is a cheap new unit but I suppose it could be bad already.

D
Click to expand...

Yes the pickup coil inside the distributor that you set the gap at, I've had 3 go bad on 3 different BB's over the years.
 
Well you just verified that you have enough voltage to fire the coil on the positive side and you are not get a ground to the coil either from the dist. or ecu.
The magnetic pickup tells the ecu when to ground the coil.
TXDart
 
TXDart said:
Well you just verified that you have enough voltage to fire the coil on the positive side and you are not get a ground to the coil either from the dist. or ecu.
The magnetic pickup tells the ecu when to ground the coil.
TXDart
Click to expand...

Hmmm, then the conclusion would be that no power is getting to the pickup either from a bad ECU or pickup. Is that reasonable?

Oh, and TXDart, is that Avitar a picture of you? Good to meet you! (Wink)
 
Since it seems you have energy from the coil, did you verify that the distributor is spinning and that the problem isn't mechanical? (broken shaft, broken cam, broken timing chain).
 
I disagree IF---- you stated that you have 6V at the coil when cranking

NOW THIS IS IMPORTANT----

How did you "crank" the engine?

IF you measured the coil pos. "cranking" while jumping across the starter relay, you will be reading through the coil resistor-- a meaningless test in this case

BUT IF you measured this 6V at the coil while using the key to crank, THIS IS NOW WHERE ENOUGH voltage.

The battery should be ABOVE 10.5V when cranking. The coil should measure NEARLY the same, maybe 1/2 volt lower

HERE IS WHAT I would try, if you did measure while using the key to "crank."

Take a clip lead (from Radio Sh$$ if nowhere else) and jumper TEMPORARILY from the big stud on the start relay directly to the coil positive.

Now see if it has spark, and if not, confirm that you are getting ABOVE 10.5v at the battery when cranking.

So far as "setting the gap by eye" this isn't gonna cut it. I stated somewhere else that I suspect these pickup coils lose magnetism. Some of them seem pretty critical. The problems with the reluctor are:

They call for .008 which 'ain't' much. If the dist. is worn, this can cause a collision with the reluctor. Also, when the vacuum advance moves, that gap can change--for the worse.

Yet another way to check for the voltage problem is to "bump" the engine until it's around halfway between reluctor "tits." Then "normal up" the system with the cap off and the key on, or better yet with your clip lead from coil + to the battery.

Now with the coil wire close to ground, grab the rotor and "snap" it smartly against the advance springs. Look to make sure you moved the reluctor "tit" past the pickup center. It just might generate a nice big spark
 
67Dart273 said:
I disagree IF---- you stated that you have 6V at the coil when cranking

NOW THIS IS IMPORTANT----

How did you "crank" the engine?

IF you measured the coil pos. "cranking" while jumping across the starter relay, you will be reading through the coil resistor-- a meaningless test in this case

BUT IF you measured this 6V at the coil while using the key to crank, THIS IS NOW WHERE ENOUGH voltage.

The battery should be ABOVE 10.5V when cranking. The coil should measure NEARLY the same, maybe 1/2 volt lower

HERE IS WHAT I would try, if you did measure while using the key to "crank."

Take a clip lead (from Radio Sh$$ if nowhere else) and jumper TEMPORARILY from the big stud on the start relay directly to the coil positive.

Now see if it has spark, and if not, confirm that you are getting ABOVE 10.5v at the battery when cranking.

So far as "setting the gap by eye" this isn't gonna cut it. I stated somewhere else that I suspect these pickup coils lose magnetism. Some of them seem pretty critical. The problems with the reluctor are:

They call for .008 which 'ain't' much. If the dist. is worn, this can cause a collision with the reluctor. Also, when the vacuum advance moves, that gap can change--for the worse.

Yet another way to check for the voltage problem is to "bump" the engine until it's around halfway between reluctor "tits." Then "normal up" the system with the cap off and the key on, or better yet with your clip lead from coil + to the battery.

Now with the coil wire close to ground, grab the rotor and "snap" it smartly against the advance springs. Look to make sure you moved the reluctor "tit" past the pickup center. It just might generate a nice big spark
Click to expand...

Tested the + coil terminal while cranking through the key and it is showing 10.4 volts. I checked the reluctor, and because the pickup baseplate rocks somewhat, the top of the pickup is slightly farther away from the reluctor-and it is about as close as I can get it so I won't dare get it closer as it will touch. Just tried jumping the + side of the coil to the battery then cranked it and checked for sparks at the plug - nothing.
 
DFX 340 Duster said:
Since it seems you have energy from the coil, did you verify that the distributor is spinning and that the problem isn't mechanical? (broken shaft, broken cam, broken timing chain).
Click to expand...

Spins fine. Everything mechanical seems fine too.
 
OK, you've already tried the box, it's getting voltage, I'd say it's a tossup--either round up another coil or replace the pickup.

Make sure you follow the recommendation for the coil / resistor combination
 
Trying a used ecu is not a true test. These boxes need to be properly grounded before the harness connector is placed on them too.
There isn't much of anything else that will come and go as you described.
 
RedFish said:
Trying a used ecu is not a true test.
Click to expand...


Actually, if you have used/ tested it previously, it's more reliable a test than a "new box out of the box."

RedFish said:
These boxes need to be properly grounded
Click to expand...

and THAT I should have mentioned. I find it odd that Mopar did not provide a separate ground pigtail through the connector, especially since they are painted or chromed
 
67Dart273 said:
OK, you've already tried the box, it's getting voltage, I'd say it's a tossup--either round up another coil or replace the pickup.

Make sure you follow the recommendation for the coil / resistor combination
Click to expand...
Still have not found the source of this issue. Took the dizzy off and looked at the pick-up. The wire to the pick-up looked as if it was rubbing on the pick-up base plate and wore through. I'm sure it shorted out. But I replaced the pick up (while at it, changed the advance curve less 2* and put in a weaker spring). After reinstalling it, still no spark. I just read a new post where someone had the same issue so I will try those potential solutions as well. I have another ECU and will try that but I'm going to test my fusible links again as I bypassed the Ammeter a few months back.
 
Did you ever set the reluctor gap "properly" with an .008 feeler?
 
67Dart273 said:
Did you ever set the reluctor gap "properly" with an .008 feeler?
Click to expand...
Yes. The gap is good. I just rechecked the power to the coil with the ign. on and a lead from the negative terminal to a ground - to check for spark. And that's good. Rechecked the tower for ohms and getting 10K ohms. That's good. Regrounded the ECU and checked for spark at the tower - nothing.
 
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