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Petronix Question Unanswered

Discussion in 'Early CJ5 and CJ6 Tech' started by tcfeet, Nov 18, 2019.

  1. Nov 18, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    May 30, 2009
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    Can someone tell me how long you can leave the key on, without starting the engine
    before damaging the Petronix module ?
    Petronix seems not to care, as I've not heard back from them...
    Thanks
     
  2. Nov 19, 2019
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    Why would that damage the pertronix, having the key on, bot not starting the engine?
    Why would you leave your key in the on position without starting the engine?
     
  3. Nov 19, 2019
    fhoehle

    fhoehle Sponsor

    Harford Township, PA
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    I have never had trouble with leaving the key on, my kids have bumped the key on plenty. I have heard of friends who have had to replace their Pertronix however. Related or not, I would try to shut it off when not running. I am just not sure but I try to not have the key on, use the accessory position if possible.
     
  4. Nov 19, 2019
    TonyM

    TonyM Member 2023 Sponsor 2022 Sponsor

    Middle Tennessee
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    In the spirit of full disclosure, let me preface this post by saying that the Pertronix Ignitor (a 6volt negative ground unit) that I received a couple weeks ago was found to be defective when I bench tested it before installation and I'm awaiting a replacement from them - so I have no first hand, real world "working" knowledge of the unit(s).

    You REALLY need to talk to Pertronix about the specifics of your question. I've found that their techs are helpful and easily accessed by phone and email. Once you've talked to a tech, they like for you to talk to the same tech moving forward during your install and troubleshooting/follow up (if required) because they supposedly keep notes and can help you more effectively if you're just dealing with one person.

    This being said, I've read online that the Pertronix Ignitor II and Ignitor III units are not suspect to damage from leaving the key "on" without the engine running due to changes in design, but that the original series Ignitor I's may be. I've also read that it could be as little as 15 minutes in the "on" position for damage to occur to series I units BUT this is all anecdotal info I found online. It should not be considered 100% accurate and I would not base any decisions on this info alone.

    Here's what I do know....The following is directly from the "common questions and answers" in the instructions that came with my Ignitor Series I 6 volt negative ground unit:

    Q. What happens if I leave the ignition switch on when the engine is not running?

    A. This can cause your coil to overheat, which may cause permanent damage to the coil and Ignitor.


    As I understand it, coil damage from leaving the key in the "on" position is also possible when using points based on the position (open vs. closed) of the points when the engine is shut off.
     
    fhoehle and 65CJ5 SRD like this.
  5. Nov 19, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    As I recall, it isn't good for a points/coil setup to leave it on, not running.
     
    fhoehle likes this.
  6. Nov 19, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    No, if the engine stops with the points closed the coil can heat up & the expanding oil may cause a leak, the points may heat up & oxidize & eventually your battery will die.
     
    fhoehle likes this.
  7. Nov 19, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    May 30, 2009
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    The reason I'm asking, I have an electric fuel pump. After it sits for 2-3 weeks I need to let
    the fuel pump build up pressure before starting, usually takes 30 second or so.
    It would be simple to add a switch between the key and coil if it would be critical.
     
  8. Nov 19, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    If the pertronix won't take 30 seconds of juice then I'd be very surprised. :shock:
     
    Jrobz23 likes this.
  9. Nov 19, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    I would not worry about 30 seconds. A lot will depend on the resistance your coil too, and whether you remove the ballast resistor.

    An oil pressure switch on the electric fuel pump would be a safety improvement, and avoid the entire issue. Then install a spring-loaded toggle on the dash for priming the fuel.
     
    fhoehle likes this.
  10. Nov 19, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    My question would be why does it take the fuel pump that long to build up pressure.
     
    Beach66Bum and PeteL like this.
  11. Nov 19, 2019
    44bz

    44bz Member

    Oregon City OR
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    I have a Pertronix kit and matching coil in my 68 J2000. I added a Holley red fuel pump because mechanical pumps for the AMC 327 are hard to come by and I was having issues with fuel siphoning back to the tank. My truck regularly sits for at least a week in between starts and I only ever have to run the pump for maybe 5 seconds before starting, at the most. It has never seemed to impact the reliability of my Pertronix kit.
     
  12. Nov 20, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    ???????????????
     
  13. Nov 20, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Use an oil pressure switch to control the fuel pump relay. The fuel pump will then only run when cranking, or when the engine is running. This is a safety measure that turns off the fuel pump if the engine stops running and the key is on. Common thing - some easy research for you.

    Holley 12-810 Fuel Pump Safety Pressure Switch
     
  14. Nov 20, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    I always turn the pump on before cranking after it sits for several days to fill the carb.
    The question I asked was; how long can the key be in the on position with the engine not running,before it damages the module...[I already have the fuel pump switch wired]
     
  15. Nov 20, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    If the oil pressure switch stuff does not make sense, just separate the ignition from the carburetor priming. Prime without turning the key on. It's the ignition that heats up the Pertronix, not the fuel pump.
     
  16. Nov 20, 2019
    baldjosh

    baldjosh Member

    pacific north west
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    I spoke with pertronix a few weeks ago about this very issue...couple hours not so good...24 hours:cry:BAD...
    carb issue...had it running and fiddling with things, once it died I threw up my hands and walked away...for 24 hours:cry:
    I don't think I got a real definitive answer from the guy but I would think from his response a few minutes would be safe...but then again who knows...I don't think there is a real cut and dry answer to the question.
    I did buy another pertronix...this time the pertronix II...supposed to be able to leave the key on but even with that there info says something like "helps protect" or "guards against" :whistle:
    in any case...lesson learned the hard way
     
    tcfeet likes this.
  17. Nov 20, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    Thanks baldjosh,
    That is what I wanted to know, not how to install a fuel pump.:)
     
  18. Nov 20, 2019
    tcfeet

    tcfeet Member

    east of west,...
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    I just got a reply from Petronix ! They test them for 5 minutes or slightly longer, so fly at your own risk any longer.
     
  19. Nov 21, 2019
    baldjosh

    baldjosh Member

    pacific north west
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    Glad you got a solid-ish answer from them...sounds like you will be fine (y)
    were all just thinking of answers from different perspectives...Brainstorming with no hands on knowledge of the issue at hand...Tim, as are many here, is a wealth of knowledge...but we all go at problems a little differently.
    Thinking out side the box can result in some good stuff.
     
    PeteL likes this.
  20. Nov 21, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I'm not sure what to think about this response. I don't think anyone told you how to install a fuel pump. I believe the answers were trying to help you work around any potential damage to the Pertronix. :shrug:
     
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