Spark/Igition help

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norville

norville

Joined
Nov 11, 2003
Threads
104
Messages
539
Location
Mountaintop, Pa
Folks, I'm having some trouble with my ignition on a pre 75 FJ40 like vehicle. First let me say I've converted my points to a pertronix kit.(I realize this may be the problem)

So, I had a hard time starting the vehicle the other day. My ignition stuff is in fairly decent shape new plugs, cap and rotor and less than 10k on the plugs wires and coil. It fired at first but, stalled when I left it to warm up and I couldn't get it restarted. My only thought is I have a universal ignition key switch and when I turned off the key the engine bumped?? I figure it's the switch so I grabbed another one and that's not it. It still bumps the starter.

I changed the coil wire and later that day it started up. After 2 days sitting I decide to take it to work. She fired right up, all is well 1/2 way to work (10 mins) The engine cuts out dead not even trying to run. I notice when I crank it the tach is not spinning, So I grab the the wire and coil wire, give them all a jiggle thinking this is where the problem is. My "new" coil wire is a bit on the short side, thinking the engine torquing is stressing the the wire. And it worked and I drove another 300 yrds and it happened again, played again and drove it home. I have been unable to get it started since the. I put on new wires and a new coil.

Best I can tell I have 12v to the coil(internal resistance coil) I'm not getting any spark from the plugs.. I'm thinking it's the pertronix.. but why doesn't the tach work?? It's connected to the neg- post on the coil and it's ben there for over a year now. Should the tach crank with the starter??


any thoughts or help would be appreciated..

bob
 
Put a test light probe on the - side of the coil and ground the clip end of the light and have someone try to start the engine. If the pertronix is working, you should see the light blink with engine speed.
 
Pinhead, I think that confirms my suspicion, My tach runs off the neg- side. and tach no worky. I have a hand held tach/points/dwell meter. that hooks from the neg side coil and to the battery and nothing working there.

thanks for the input. Do you know whay it effect the neg side of the coil? Just curious to learn what's happening...

bob
 
Ok, I removed pertronix kit. I put in new points and condenser. It had it running, something was not correct. but it was idling and running on its own then it just cut out!!! Again I'm not getting anything at the tach or the dwell meter. points are adjusted correct. it had OK dwell, when it was running. I felt it just needed the timing tweaked. Again nothing??

I have 12v to the coil. What am I missing?

I could try a known good coil?

Could the alternator be doing this??

Lastly is there some wiring or relay that I'm not aware of killing power to the engine? Does the engine run on the battery or the alternator??
 
3doghouse said:
Make sure the distributor body is well grounded. Run a ground straight from battery (-) to the distributor housing if necessary for testing.

If that doesn't help, test the coil per: https://forum.ih8mud.com/40-55-series-tech/196883-testing-ignition-coil.html
Click to expand...



Thanks 3 dog I'll try that tomorrow. What I find odd is it was running And I had pulled a plug right after I put in the points to check the spark. Lots of good spark. And I had it running off and on for 1/2 hour the engine was actually warm when it just quit. One other thing I should mention I thought it was timing related it had some difficultly starting (hot start) but it would catch.

Do coils kinda go?? I know sometimes they get hot and go out?

My other thought was chassis ground?


bob
 
If it is an intermittent problem, it is hard to locate because you have to catch it in action. Try running a hot wire directly from the battery + to the coil + and see if it is more reliable. Timing is not an intermittent issue.
 
Pin_Head said:
If it is an intermittent problem, it is hard to locate because you have to catch it in action. Try running a hot wire directly from the battery + to the coil + and see if it is more reliable. Timing is not an intermittent issue.
Click to expand...

Ah man great thought. It kills me sometimes when it's my stuff thats broken I can't think clearly.

bob


Wait, I have 12v to the coil, just no spark from the plugs?

coil
coil wire
distributor cap
rotor
ground


bob
 
Last edited:
Get a good grounding wire to the block, and another wire from +batt to + coil . then
Do a coil test for spark without the HT wire, to see If you are getting a steady spark and take it from there.
Do the coil test when you are having the problem.
I remember the other post about a similar problem, after 2 pages ,it turned out to be a the HT wire (very simple).
It has to be either a bad connection or a bad componant.
JUST REPEATING WHAT HAS BEEN SAID ALREADY.
Vic
 
I think I got it. pretty simple but man it was a long road. I much prefer armchair-ing these things.

I 99% sure it's the distributor the shaft has some wiggle. I swapped out the new dist cap and rotor and it worked for a few minutes then nothing again. I know the coil is good I have ground. I pulled the cap off and watched the engine crank I have now spark. I adjust the points for the 100th time I have spark I put it together and she fire up and stops. Hmmmm Now it's clicking, the shaft is wiggling enough to cause it to be out of spec on the points. now I have a real problem....


bob
 
norville said:
I think I got it. pretty simple but man it was a long road. I much prefer armchair-ing these things.

I 99% sure it's the distributor the shaft has some wiggle. I swapped out the new dist cap and rotor and it worked for a few minutes then nothing again. I know the coil is good I have ground. I pulled the cap off and watched the engine crank I have now spark. I adjust the points for the 100th time I have spark I put it together and she fire up and stops. Hmmmm Now it's clicking, the shaft is wiggling enough to cause it to be out of spec on the points. now I have a real problem....


bob
Click to expand...
If you don't want to fix your dist, I have one that was in my truck, points type , excellent working . you can have .
I can't see me using it again.
You can just put on or put the ptronix kit in it.
Vic
 
Vicm said:
If you don't want to fix your dist, I have one that was in my truck, points type , excellent working . you can have .
I can't see me using it again.
You can just put on or put the ptronix kit in it.
Vic
Click to expand...


I appreciate that. That's why I like this board so much, lots of helpful folks, and generous to boot... I wish it was that easy.

Here's the vehicle is question:
IM002109.webp
 
norville said:
Wait, I have 12v to the coil, just no spark from the plugs?

bob
Click to expand...

Just because you measure 12V at the coil + post doesn't mean that it has enough power to spark. Power is volts times amps and you need to have both.

If you measure 12V with an open circuit, you could be getting fooled because there are no amps flowing. Try measuring it when the points are closed or when the - side of the coil is grounded. If the voltage drops to less than 6V with the points closed, then you have a problem with the ingition power circuit.
 
Pin_Head said:
Just because you measure 12V at the coil + post doesn't mean that it has enough power to spark. Power is volts times amps and you need to have both.

If you measure 12V with an open circuit, you could be getting fooled because there are no amps flowing. Try measuring it when the points are closed or when the - side of the coil is grounded. If the voltage drops to less than 6V with the points closed, then you have a problem with the ingition power circuit.
Click to expand...

Great point pinhead, I did measure 12v with points closed and at the 2 jump points in the dizzy. I also measured full open to ground with the points open on the points plate. That was when I would get no tach feedback = no sparking.

as soon as I'd re-adjust the points it would start up then stop and no spark.

My theory is that I'm clost and the wobble is taking me out of spec when the engine fires.

Does that sound logical. I'm tired of chasing ghosts.....

bob
 
That's cool!

It's a Patrol, right? I don't know much about them, or parts availability, but if a new one is hard to find, you may be able to get it re-bushed.
 
norville said:
My theory is that I'm clost and the wobble is taking me out of spec when the engine fires.

Does that sound logical.
Click to expand...


No. Not really.

If it was bad enough wobble to kill the engine it would be bad enough that it wouldn't ever run, even though it might pop and fire occasionally.
 
Well the points are in and she's running. I pulled the dist and and shimmed the bottom of the jigger that holds the weights and is the hexagon rubbing block. I had some play in there. I also greased it a bit hoping to take up some slack.

FIT the pertronix is toast. I could not get it to work again.

I'm running about 39deg of dwell. which I really like, I still have a hitch in the idle and I cannot get her below 750rpms. so more work is needed. Also I'm pretty sure the advance is to high cause I get a hot start situation when warm. And I'm nearly maxed out which isn't correct. vac leak?

but she ran for more than 1/2hour no stopages.

bob
 
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