Register now to get rid of these ads!

Technical Pertronix Ignition Problem Has Me Stumped

Discussion in 'The Hokey Ass Message Board' started by brianf31, Aug 21, 2020.

  1. brianf31
    Joined: Aug 11, 2003
    Posts: 702


    Yesterday I swapped the cam in the coupe. It fired right up and was running fine while I set the idle, adjusted the timing, tuned the idle mixture, etc. I went back to check the timing and it abruptly died while I was shooting the light. Not a "fuel system went bad" putter but a quick. electrical style kill.

    I have the original style Pertronix Flame Thrower distributor and their 1.5 ohm coil. There is no spark to the plugs; the timing light won't blink and there's no spark when pulling a wire and holding it near ground.

    I started chasing down the whole electrical circuit. All of my checks and tests were good.

    12.70 V across the battery posts
    12.70 V at the solenoid.
    11.99 V at the coil using a jumper from coil neg to ground (Pertronix spec is 8.0 V min)
    .4 ohms from batt neg to distributor base plate (within Pertronix specs - .2 ohms from leads and .2 ohms from circuit) so no ground issue

    Ignition module test passed: multimeter reading alternated between 12.63 on each magnetic sleeve peak and 0.09-.11 V (theoretically should be 0) on the flat as I rotated the engine.
    Air gap between sleeve and sensor at nominal .030"
    All wire ends free of corrosion and tight.

    The ignition system has less than 2000 miles on it; plug wires are are in good shape and the rotor and cap do not have any obvious wear, corrosion or cracks.

    Is it possible to get a "pass" on the ignition module test on a bad module?
  2. What's the condition of the coil?

  3. petew
    Joined: Jul 21, 2010
    Posts: 220

    from Mebane, NC

    I’ve been down this road and I generally do exactly what you did and then ....
    Try a different coil and if that doesn’t work put the points and condenser back in , if it runs you need a new module.
    Not very scientific but gets the job done.
    I think that Pertronix makes a good product and I have them in 3 of my cars .
    I know that with the original module leaving the key on without the engine running ruins the unit. In speaking with their tech people they admit that they do fail but not very often.
  4. kabinenroller
    Joined: Jan 26, 2012
    Posts: 674


    I have a Pertronix distributor and the matching coil in the Cyclone, it is new and not many miles on it but I am prepared for what I have heard from other users. The coils are prone to failure, I will be carrying a Bosch coil as a spare (1.5ohm) I already have a spare module in the tool kit. Pertronix work well, until they quit.
    Driver50x and warbird1 like this.

  5. brianf31
    Joined: Aug 11, 2003
    Posts: 702


    Brand new 1.5 ohm Pertronix Flamethrower. I just swapped it after she quit running.
  6. brianf31
    Joined: Aug 11, 2003
    Posts: 702


    Yep. I'll pass Summit on the way to the SEGA race tomorrow. I think I'll pick up a module. Worst case, I'll have a spare.
    Truckdoctor Andy and catdad49 like this.
  7. blowby
    Joined: Dec 27, 2012
    Posts: 7,747

    from Nicasio Ca

    Disconnect the module from the coil. Put a jumper wire on the coil - and scratch to ground, key on, see if the coil wire has a spark.
    loudbang and brianf31 like this.
  8. 32SEDAN
    Joined: Jul 30, 2008
    Posts: 1,298


    Had a similar issue. Module failed intermittently. I would replace the module and ensure your ground is solid

    Sent from my iPad using H.A.M.B.
    brianf31 likes this.
  9. Stan Back
    Joined: Mar 9, 2007
    Posts: 1,075

    Stan Back
    from California

    I had their units in my 354 Chrysler. Left me stranded all of a sudden three times. Good ol' Auto Club.

    I took the units back to them personally twice. I asked to see the technician test them. "Sorry, insurance regulations, we can't do that." Each time, after an hour, they brought out a new unit, "There's nothing wrong with your old one, but we've replaced it just in case."

    Third time I converted back to stock.
    Gasser 57, loudbang, TagMan and 2 others like this.
  10. I know everybody will jump down my throat, but I’d put the points in and leave it that way.
  11. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,912

    dirty old man

    I've been running a complete MSD system, dist, box, and coil for several years with no problems except a coil that went bad because I had it under the dash where no air could get to it and it overheated and shorted the windings.
    Points are OK if you don't mind changing them and the plugs frequently.But that's only if you an manage to find a supply of decent, NOS US made points and condensers. And that is a damn big IF nowadays,
    Last edited: Aug 22, 2020
    Roothawg, belair, loudbang and 2 others like this.
  12. Try calling Pertronix.....they gave me a new module free when the original one died right out of the box. Been working great ever since......over 25 years ago.....
    loudbang likes this.
  13. Chrome Moly Steel
    Joined: Aug 21, 2015
    Posts: 50

    Chrome Moly Steel
    from Miami, fl

    Recently there was a post with a similar problem. I believe the tach was the cause of the ignition failure. May be worth disconnecting the tach to see what happens.
  14. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 626

    from 94577

    With electronics, a thermal failure will only show up when the component is heated/loaded to operating temps/conditions.
    I know folks state the Pertronix system is 'junk' yet I've had more Ford TFI and Duraspark pickups die on me than any Pertronix module that was correctly installed.

    Out of curiosity, why did you do this?
    If the circuit was working prior, adding a jumper to test kind of negates the test.
    Test in situ, if you find a fault then figure out the fault, don't start adding jumpers to prove out a part, find the reason why a part is not getting power or ground.

    FWIW, the Petronix I will die sooner if the ignition system is left 'ON' with engine 'OFF'. It may not die right away but it can cause the system to degrade quickly or die while running.
    I prefer the Petronix II system as it avoids this potential problem as it safeguards itself.
    belair, loudbang and Truckdoctor Andy like this.
  15. Bonehead II
    Joined: Apr 18, 2005
    Posts: 428

    Bonehead II

    I'm with you...
    loudbang, Stllrng. and 427 sleeper like this.
  16. Mimilan
    Joined: Jun 13, 2019
    Posts: 894


    These ignition modules work pretty good

    The problem these days is finding a good condenser
    this is an interesting read:

    When we rebuilt the engine in our 57, we had 2 condensers fail out of the box! [we are now using the original rescued from the trash]

    I've had 2 Mallory tach's do that with an HEI [it was the dial-in rev limiter feature ]
    A MSD module with the limiter, and an Autometer sport comp tach was the answer
    Last edited: Aug 22, 2020
    Moriarity, loudbang, Stllrng. and 2 others like this.
  17. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,274


    Remove the wire going to the distributor jumper the coil post to ground momentarily you should secondary spark from the coil. No spark coil spark module. All the module does is turn the ground on and off.
    Last edited: Aug 22, 2020
    loudbang and Driver50x like this.
  18. Rice n Beans Garage
    Joined: Dec 17, 2006
    Posts: 1,554

    Rice n Beans Garage

    My tach grounded and caused my no spark !
    dirty old man, sunbeam and loudbang like this.
  19. tubman
    Joined: May 16, 2007
    Posts: 5,733


    "PERTRONIX IGNITION PROBLEM HAS ME STUMPED". Me too. Stumped as to why people still insist on running these things.
  20. SicSpeed
    Joined: Apr 23, 2014
    Posts: 653

    from Idaho

    I couldn’t agree more. I’ve seen friends have trouble with this brand from day one. I wouldn’t run one in the lawn mower

    Sent from my iPhone using The H.A.M.B. mobile app
  21. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 1,279

    427 sleeper

  22. I’m not sure what it means to change points “frequently”; I have been driving vehicles with points since 1977. I really haven’t had to change that many sets on my drivers. I changed the points in my 1977 FLH Harley-Davidson because it seemed like I should. They had been in for 10 years and looked just fine.
  23. simplyconnected
    Joined: Jun 5, 2009
    Posts: 64


    I found my reluctor wasn't 'level' with the pickup. Don't laugh. I got NO spark until I made the change. Afterward, no problem. No, I wasn't smart enough to figure this out on my own but a phone call to Pertronix was all it took.
    dirty old man and loudbang like this.
  24. 6-bangertim
    Joined: Oct 3, 2011
    Posts: 400

    from California

    I've always used a test light to test a module. Connect between ground and negative(-) side of the coil. With the key ON, the light should glow bright. Crank the engine, light should cycle between bright and dim for a good unit. If the light remains bright, module is bad. Works on any electronic ignition, even ferrin cars!
    dirty old man and brianf31 like this.
  25. Black Panther
    Joined: Jan 6, 2010
    Posts: 1,764

    Black Panther
    from SoCal

    I like traditional.....points. Isn't the premise of an electronic ignition supposed to be that it is trouble free? Sound like there are many ways to screw up a Pertronix setup. Wrong ohm rated coil, left the key on, intermittent bad modules, ground issues, now alignment of internal ignition parts? Sounds like a pain to me. But wait, you'll say...once you get it all figgered out, it'll last a long time. Dont want to go on that journey when there already was a simple solution....
    Last edited: Aug 23, 2020
    Stllrng., X38 and Moriarity like this.
  26. brianf31
    Joined: Aug 11, 2003
    Posts: 702


    Winner, winner, chicken dinner! I unhooked the tach and it fired right up. This is problematic since I drive by the tach; I don't have a speedometer. I'll have to fix that issue.

    This is strange since the Bosch tach has worked fine until now. Off to research...
  27. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,912

    dirty old man

    OK, I don't think we are exactly being topical with the Harleys, so I'll move on to the rest of your vehicles and how you didn't have to change points too often.
    I'm going to use an OT GMC 4X4 p'up I had as an example,as it's the best illustration I can give, so I hope the moderators will forgive me and allow that one mention of being OT . It was equipped with a 4BBL Quadrajet, exhaust headers with dual glasspacks and 2.5" pipes and hi lift rockers.
    Truck was geared way too tall w/ 3.08 gears and 33" tires, and for sub 55 mph passing on 2 lane roads of GA you had best use 3rd gear in the "Granny Low" 4 spd trans. for a passing gear and it was good acceleration to on up past 80mph! I was doing work by the job, and if not at work site doing my work, I wasn't making money. So I did A LOT of passing! Maybe yall don't get in a big hurry like that up there?
    When that truck was well tuned, it was quick in spite of it's weight and too tall gearing if you used those 4 gears. But when you got about 9-10K miles on those plugs and points it started laughing at you above about 4K rpm. New points and plugs would restore the performance till next time.
    Then MSD came out with their first CD, multi spark box, which I installed. These early units used the points to trigger the box, and transferred only a tiny bit of current rather than the full load of the ignition coil.
    All the attention the points needed from then on was rubbing block wear requiring a dwell adjustment in about 50K and the plugs also would fire the engine to valve float rpm for about the same mileage because they were getting a much higher voltage spark due to the CD sending much higher voltage to coil primary windings instead of 12v.
    I've watched Brian twist that Ford Cleveland to rpm well above stock ignition system capability at Run What Ya Brung events @ Silver Dollar Motorsports Park in Reynolds, GA.
    Glad you found the tach to be the problem Brian. Do you plan to try another tach or what?
    brianf31 likes this.
  28. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 626

    from 94577

    Might be a bad connection in the system, recheck your wiring and the ignition systems wiring as well as the engine block to body/frame ground(s).
    Can you test the tach on another vehicle?

    I've had a few go bad that were of the parts store type. Knockoff Sun(Equus) tach and a Bosch unit. Equus unit just started reading wrong rpms, regardless of switch. Bosch danced the needle a few times and then quit.
  29. carcruse
    Joined: Aug 20, 2007
    Posts: 861


    We had same problem and solution with my brothers car about 6 years ago. Disconnect electric tach wire from coil and it fired right up.
    brianf31 likes this.
  30. brianf31
    Joined: Aug 11, 2003
    Posts: 702


    After taking a look at my wiring diagram today, I realized the wire I detached from coil negative was not going straight to the tach but to the Pertronix 600 rev limiter (which also sends signal to the tach). Looks like I need to check the wiring for the rev limiter.
    Petronix 600.jpg Petronix 600.jpg

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.