Checking HEI distributor with a meter
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Joined: Jun 2008
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From: Johnson City Tennessee
Checking HEI distributor with a meter
I have a 79 I just swapped motors on & kept my HEI distributor. It worked before but now I have no spark. Just to eliminate some possibilities of the problem I've refereed to the Haynes book for how to check it with a meter. $5 at Harbor Freight later I've got a meter & here is what the book says.
Haynes book 24040 Chapter 5-7
HEI-type coil-in-cap (1975 & later models)
... "#7 Using the high scale, attach one lead of the ohmmeter to the high-tension terminal in the middle of the distributor & the other lead to each of the primary terminals. If both of the readings indicate infinite resistance, replace the coil. "
Not exactly sure what "high scale" is but I tried it on every ohm setting & got " 1 . " just like in the photo 12.6b. I'm pretty sure thats infinite because thats the same thing it says when the leads aren't touching.
I got this reading on this distributor that I know worked a few months ago. I also did the same test on my other distributor that is practically new with the same result " 1 . " Both of these distributor coils being bad seems highly unlikely.
Granted, I don't really know what I'm doing & I'm probably doing something wrong (most likely) or the book has a typo. What can I do to eliminate some human error here?
Haynes book 24040 Chapter 5-7
HEI-type coil-in-cap (1975 & later models)
... "#7 Using the high scale, attach one lead of the ohmmeter to the high-tension terminal in the middle of the distributor & the other lead to each of the primary terminals. If both of the readings indicate infinite resistance, replace the coil. "
Not exactly sure what "high scale" is but I tried it on every ohm setting & got " 1 . " just like in the photo 12.6b. I'm pretty sure thats infinite because thats the same thing it says when the leads aren't touching.
I got this reading on this distributor that I know worked a few months ago. I also did the same test on my other distributor that is practically new with the same result " 1 . " Both of these distributor coils being bad seems highly unlikely.
Granted, I don't really know what I'm doing & I'm probably doing something wrong (most likely) or the book has a typo. What can I do to eliminate some human error here?
Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
Seeing as how you have a spare distributor and coil, simply remove the coil from the one in the engine, and replace it with the coil from the spare. Not too hard...four screws, and make sure everything gets put in the way you take it out.
I have a feeling you just have a bad coil and have been testing it wrong.
Something you can test for sure though is to make sure he pink wire is switched 12V and that all plugs are in their proper locations.
I have a feeling you just have a bad coil and have been testing it wrong.
Something you can test for sure though is to make sure he pink wire is switched 12V and that all plugs are in their proper locations.
Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
Okay so one of them is a newer computer controlled unit?
I don't know if they are similar or not. You can pull it apart and see for yourself...that's how I check for things sometimes.
If not, you can buy a new coil for your distributor very easily an cheaply at almost any local parts store.
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From: Johnson City Tennessee
Just tried it & the coil wont come out of the spare. The coils look the same (as best I can tell) but I'll destroy the cap getting it out. Seems like its melted in there from the the factory or something.
I'll run to the auto parts store later & get them to check mine & if it is in fact bad just get a new one.
It just seems really odd to me that it would go bad sitting on a shelf without dropping it or spilling beer on it or something.
I'll run to the auto parts store later & get them to check mine & if it is in fact bad just get a new one.
It just seems really odd to me that it would go bad sitting on a shelf without dropping it or spilling beer on it or something.
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
Make certain there's No connection between Bat & Tach terminals at hei dist cap.
switch key to RUN position ... do Not crank ... probe cap connections with VOLT meter ... you should see ~11-13v at BAT terminal ... you should see No voltage at TACH terminal.
With key OFF, test continuity between Bat & Tach terminals ... there should be No continuity.
If something metal got up into cap connections & bridged across Bat & Tach terminals, it's likely fried something. Just making a connection while switch on can do it if you're just a 1/4" off.
switch key to RUN position ... do Not crank ... probe cap connections with VOLT meter ... you should see ~11-13v at BAT terminal ... you should see No voltage at TACH terminal.
With key OFF, test continuity between Bat & Tach terminals ... there should be No continuity.
If something metal got up into cap connections & bridged across Bat & Tach terminals, it's likely fried something. Just making a connection while switch on can do it if you're just a 1/4" off.
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From: Johnson City Tennessee
Well the guy that knows how to use the testing machine wasn't in at Auto Zone but they had a coil in stock so I got it. I put my meter on it & got the exact same " 1 . " so either I really don't know what I'm doing wrong with the meter or the coil isn't the problem.
I'll just pull the whole distributor & take it in to get him to check everything out on it tomorrow.
I'm still not entirely convinced that its even a distributor problem because it worked the last time the old motor was run.
If it turns out that it's not anything to do with my distributor where do I need to start checking?
I'll just pull the whole distributor & take it in to get him to check everything out on it tomorrow.
I'm still not entirely convinced that its even a distributor problem because it worked the last time the old motor was run.
If it turns out that it's not anything to do with my distributor where do I need to start checking?
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Le Mans Master
Joined: Jan 2003
Posts: 6,575
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From: Tuttle OK
Cruise-In VIII Veteran
If you're not getting spark, check your pickup coil.
Instructions are in the GM book. If you need them, shoot me a pm.
Instructions are in the GM book. If you need them, shoot me a pm.
Last edited by Avette4me; Oct 1, 2008 at 09:16 PM.
Drifting
Joined: May 2005
Posts: 1,629
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From: Somers CT
The HEI Dist MUST have direct battery voltage, make sure it's 12V and it's not coming off some other accessory at a lower voltage. Also, if I'm understanding what you've done you've put the HEI in a car that had points before............If that's true make sure you bypass or remove the ballast resistor, it won't work if you don't.
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Put your dizzy in a vise (gently) hook +12v to the battery terminal on the cap and ground the vise. Turn the dizzy gear on the bottom and see what happens,, WATCH YOUR FINGERS!! HEI HURTS BAD!!
Click on the picture for the video..
Click on the picture for the video..
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From: Johnson City Tennessee
Took both distributors to Auto Zone & they could only check the module. Both are good so I can definitively rule that part out.
Turns out my distributors are basically the exact same thing. The reason one didn't have the vacuum thing is because the motor builder (circle track motor) cut it off & welded the moving bar in place so it wouldn't move.
It's not a totally different computerized distributor & I'm not really changing anything from what was in the car or what was on the new motor because the parts swap.
I've now combined my old cap, coil, rotor & vacuum thingy to the nearly new distributors housing thats got nearly new electric stuff in it. I would think that would eliminate some guesswork of old parts failing. If not now then later down the road. (I used my old cap parts because of issues of the fitment of my air cleaner)
I'm going to try this new 2 distributors combined into 1 set up in there & see if I get any different results & go from there.
Turns out my distributors are basically the exact same thing. The reason one didn't have the vacuum thing is because the motor builder (circle track motor) cut it off & welded the moving bar in place so it wouldn't move.
It's not a totally different computerized distributor & I'm not really changing anything from what was in the car or what was on the new motor because the parts swap.
I've now combined my old cap, coil, rotor & vacuum thingy to the nearly new distributors housing thats got nearly new electric stuff in it. I would think that would eliminate some guesswork of old parts failing. If not now then later down the road. (I used my old cap parts because of issues of the fitment of my air cleaner)
I'm going to try this new 2 distributors combined into 1 set up in there & see if I get any different results & go from there.
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From: Johnson City Tennessee
Here is a picture of where I swapped parts between the 2 distributors. The red one is the one
going into the car now. I'll be back in a little bit to tell you what happens.
http://byfiles.storage.live.com/y1pQ...oiB9VRA0HsoP-4
going into the car now. I'll be back in a little bit to tell you what happens.
http://byfiles.storage.live.com/y1pQ...oiB9VRA0HsoP-4
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From: Johnson City Tennessee
I put the new, 2 together, distributor in & nothing happened, still no spark.
I tested the red wire that goes to the distributor, with the key on but not cranking & I'm getting 12.13 Volts. That throws a wrench into my theory about it not getting any power & the problem being somewhere else.
I'm going to try the vice video thing, just because you guys are sadistic enough to put something that torturous in front of me to play with knowing good & well I'm just masochistic enough to have to play with it.
BZZZZZ
OUCH!
BZZZZZ OUCH! LOL
I tested the red wire that goes to the distributor, with the key on but not cranking & I'm getting 12.13 Volts. That throws a wrench into my theory about it not getting any power & the problem being somewhere else.
I'm going to try the vice video thing, just because you guys are sadistic enough to put something that torturous in front of me to play with knowing good & well I'm just masochistic enough to have to play with it.
BZZZZZ
OUCH! BZZZZZ OUCH! LOL
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From: Johnson City Tennessee
OK, I tried the vice test & nothing zapped.
However I think my housing is aluminum & thats not a conductor like cast iron so this test may not work for my application.
DARN IT! I was hoping that would work so I could invite some petulant children over to play with my sparkle new toy.
However I think my housing is aluminum & thats not a conductor like cast iron so this test may not work for my application.
DARN IT! I was hoping that would work so I could invite some petulant children over to play with my sparkle new toy.
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Joined: Jun 2008
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From: Johnson City Tennessee
Thread Starter
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Joined: Jun 2008
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From: Johnson City Tennessee
If you guys seen that fire video the other day you know I had a short with the main power wire & heat shield of the solenoid. At the same time the car sputtered for about 1 second.
I had to have had a spark at that time to have a sputter but could something going on with that short have fried something somewhere else? Car didn't stop running, I cut the key off because of the fire.
Of all the times I wish I had a buddy to come over & look at it for 10 seconds & say "well, there's you're problem".
I had to have had a spark at that time to have a sputter but could something going on with that short have fried something somewhere else? Car didn't stop running, I cut the key off because of the fire.
Of all the times I wish I had a buddy to come over & look at it for 10 seconds & say "well, there's you're problem".
Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
OK, I tried the vice test & nothing zapped.
However I think my housing is aluminum & thats not a conductor like cast iron so this test may not work for my application.
DARN IT! I was hoping that would work so I could invite some petulant children over to play with my sparkle new toy.
However I think my housing is aluminum & thats not a conductor like cast iron so this test may not work for my application.
DARN IT! I was hoping that would work so I could invite some petulant children over to play with my sparkle new toy.
Yes your aluminum housing distributor would conduct electricity just the same as cast iron. You might be missing something in your assembly or it's not being connected properly. You should be able to test it on a bench vice and get spark.
You might have fried one of the two fusible links down at the starter.
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From: Johnson City Tennessee
[quote=Durango_Boy;1567347018]Yes your aluminum housing distributor would conduct electricity just the same as cast iron. You might be missing something in your assembly or it's not being connected properly. You should be able to test it on a bench vice and get spark.
quote]
Tried this test again. Something is happening but not whats going on in the video above. If there is no power then it spins silent but when I put power to it & spin it, it makes a knocking / tapping sound. NOT a zapping sound, NO visual zap.
What does that mean?
quote]
Tried this test again. Something is happening but not whats going on in the video above. If there is no power then it spins silent but when I put power to it & spin it, it makes a knocking / tapping sound. NOT a zapping sound, NO visual zap.
What does that mean?
