Another sparkless ignition

Old Jun 24, 2012 | 08:32 PM
  #1  
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Another sparkless ignition

'68 Delta 455...
No ignition problems before the motor was taken out, now it wont start...no popping, spitting, its like all the plugs are disconnected...not fuel, I can see the acellerator jets pumping, plus you can smell the gas after cranking it.

-replaced coil- with a jumper lead I get a nice painful spark out of the HT lead
-even without lead coil gets 12v-8v (depending if points are sitting open I think) Not sure about during cranking--reason for jumper lead
-replaced primary wire from dist to (-) coil..checked the wire no resistance
-measuring resistance from primary clip to dist body I get no resistance with points closed and infinite with them open
-also tried a new set of points still nothing-tested them as well and get the same values
-checked center electrode in cap, no resistance
-same for rotor electrode

At this point, is it safe to say that the fault is within the distributor somewhere?
Not sure if I missed something, searched around here and found these things to check

Possible the dist body isn't grounded? don't remember if I checked that--been a long day..

Maybe a bad condensor--any way to test?
Points are set as close as I could to .019" dwell I'm not sure about--is there even a way to set without it running?

Had it lined up as best I could at TDC on cylinder 1 to start..every other time the rotor was marked where it was and replaced the same way--but even if the timing were way out wouldn't I get something?
Old Jun 25, 2012 | 12:57 AM
  #2  
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Is the distributor actually turning when you crank?
Old Jun 25, 2012 | 05:03 AM
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It definitely is
Old Jun 25, 2012 | 05:20 AM
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Is your engine ground strap attached to the body?
( Bolted to the backside of the head off # 8 cyl. to the firewall.)
Old Jun 25, 2012 | 05:26 AM
  #5  
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I replaced it with a 6 ga wire, plus added another that goes from the front of that head to the frame (one end of the ground strap that goes to the control arm) also made sure all connections were shiny

also the spark I get from grounding the hot coil is pretty good bright and blue

Last edited by Bugg; Jun 25, 2012 at 05:29 AM.
Old Jun 25, 2012 | 05:28 AM
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Is your bypass wire from the starter solenoid providing 12 V during cranking?
Also, is there anything else hooked to the coil - lead, ie a tach?
Old Jun 25, 2012 | 05:30 AM
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The bypass goes direct from battery to pos terminal of coil but I couldn't measure it during cranking
Old Jun 25, 2012 | 05:31 AM
  #8  
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I would try a new condensor. If it is bad, no spark.
I don't know how to check it, but it has happened to
me as well. I just changed it out and it worked. I hope
it does for you too.
Old Jun 25, 2012 | 06:09 AM
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Turn the engine to #1 tdc and check yourspark plug wiring. And make sure the rotor is pointng to #1.
Old Jun 25, 2012 | 06:11 AM
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The new points set had a new condensor on it, but it's not impossible that it was bad too.....
But, the condensor that sits on the coil--that's just for radio interference which I don't care about at this point--is that useable to test out? If so how would it be hooked up?
Old Jun 25, 2012 | 06:40 AM
  #11  
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Originally Posted by oldcutlass
Turn the engine to #1 tdc and check yourspark plug wiring. And make sure the rotor is pointng to #1.
The 2 first times I tried to start it, I had both lined up (that cyl definitely has compression btw haha) but again that was with the original parts....after getting new parts I just marked the rotor as it sat and replaced it the same way...

I am going to line everything up again however once I'm ready to give it another go

Last edited by Bugg; Jun 25, 2012 at 06:42 AM.
Old Jun 25, 2012 | 06:44 AM
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At this point is there anything I can do or test without having to crank the motor? It has (had) a new cam in it, which I'm pretty much accepting is damaged or will be, but there's hope I guess :/
Old Jun 25, 2012 | 06:47 AM
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You can hook up a dwell meter and see where it is when cranking. Check to see if you getting a good solid spark at a plug when cranking.
Old Jun 25, 2012 | 07:01 AM
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Yes, that I need to get

crazy idea, but it is possible or even a good idea to- connect everything, but leave the dist uninstalled but grounded to block via cable, install one sparkplug lead grounded to verify spark, and spin it by hand?

Just brainstorming-- might be easier on the motor internals
Old Jun 25, 2012 | 11:11 AM
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There should be a spring loaded tab inside the top of the distributor cap. Any chance that fell out preventing spark from getting to the rotor.
Old Jun 25, 2012 | 11:35 AM
  #16  
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Little black tab is there, not sure if could be stuck tho

figures that I hadn't changed any ignition parts 'because I knew they worked' sigh
Old Jun 25, 2012 | 11:39 AM
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Originally Posted by garys 68
There should be a spring loaded tab inside the top of the distributor cap. Any chance that fell out preventing spark from getting to the rotor.
Very good point.

If you used a intergaded points/condensor, toss it.
I HATE those things, but that's me. I never had any
luck for very long with them. Standard, if you can find them
or better yet, Delco Remy.

My money's on the condensor. I am not sure if you can use
the radio condensor on top of the coil that is designed for
radio interferance or not. Check O'rileys, or Napa, you maybe
able to get the stand alone points/condensor. Good luck
and let us know how it all turns out.
Old Jun 25, 2012 | 04:38 PM
  #18  
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I have the integrated points condensor... Delco remy

funny thing was I went to get the points yesterday and had the separate pieces but got the integrated piece bc that's what was already in the dist....
Getting a dwell meter tonite, I'll
pick up points too
Old Jun 26, 2012 | 06:39 AM
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I would install the old point set since it worked before just as a test. I've had the uniset fail in the past. and troubleshot with a known go set. I also carry the old known good set in my trunk with an old set of wires, cap, rotor, and plugs as emergancy spares.
Old Jun 26, 2012 | 10:07 AM
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The old set was a uniset, but last night I picked up I new points set, new condensor, cap, and rotor, and dwell meter

since I'm running the coil direct to the battery, there isn't anything left right?
Old Jun 26, 2012 | 10:20 AM
  #21  
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Originally Posted by Bugg
The old set was a uniset, but last night I picked up I new points set, new condensor, cap, and rotor, and dwell meter

since I'm running the coil direct to the battery, there isn't anything left right?
Only the coil wire running to the cap. Also with your jumper to the coil, in order to turn the motor off it will need to be disconnected.
Old Jun 26, 2012 | 11:34 AM
  #22  
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I have two cap wires, both have contnuity, as well as the plug wires, so hopefully this stripped down ignition circuit will work with everything new, and now I have every part doubled up (some tripled haha)

btw the look on they guys face at autozone was priceless when I asked for a dwell meter
Old Jun 26, 2012 | 01:15 PM
  #23  
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Originally Posted by Bugg
btw the look on they guys face at autozone was priceless when I asked for a dwell meter
Wow, the look on my face to know they actually had one!
Old Jun 27, 2012 | 03:43 AM
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This isn't rocket surgery. The coil will throw a spark any time there's 12 V and you momentarily ground the - post.
So if I have this correct.
1) Your coil will spark if 12 V is applied and you ground the - post
(make sure nothing else is wired to the - post , ie tach, grounding it will kill ignition)
2) You know the distributor is turning
(Do you know if the points are opening closing? You can crank engine by hand and confirm with ohm meter)
Now you can turn ignition on, crank motor by hand, look for spark directly from coil (use a spark checker directly off the coil/distributor wire, ground the other end)
If that shows spark and yoour not getting anything at your plugs, it's in your distributor cap/rotor.
Check the tab that connects the rotor to the cap input, look for carbon tracking or cracks in the rotor/cap. You can get carbon tracking through the rotor to the distributor shaft.
Old Jun 27, 2012 | 06:39 AM
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Good news is that it was one of the parts that I replaced so now it fires...just gotta get it all lined up to run and she should be rolling soon! Was just glad it was an actual part in need of replacing and no something I did incorrectly (besides trusting 20+ yr old parts) thanks for the walk through guys
Old Jun 27, 2012 | 06:44 AM
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Good to hear, which part was it?
Old Jun 27, 2012 | 10:51 AM
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Either the cap or rotor bc the tach was registering but still no spark, changed them out n fired up
Old Jun 27, 2012 | 11:25 AM
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So change back to the old rotor to confirm which one was bad - Inquiring minds want to know!

- Eric
Old Jun 27, 2012 | 11:46 AM
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Originally Posted by mdchanic
so change back to the old rotor to confirm which one was bad - inquiring minds want to know!

- eric
x2
Old Jun 29, 2012 | 04:54 PM
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Will do, I'm curious too haha...once I have some time to get back to work on it and have it running I can toss it back on and see
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