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| Ignition | Rate Topic |
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| Posted: 12-09-2018 02:49 am |
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1st Post |
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TanDJensen Member
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I've recently restored my 74 JH which included rebuilding the 907 with a stroker crank. What an upgrade! It ran great until it didn't. Turns out I had 2 problems: after a process of elimination I discovered the existing (from a previous owner) Pertronix II magnet ring was defective as evidenced by an ignition misfire once the engine warmed, and, on the limping drive back to the shop I lost all oil pressure because- I discovered through much research- I failed to put in solid crank bearings which are required with a cross-drilled 2.2 liter crank, resulting in a loss of all oil pressure from a burnt bearing. That was a hard-earned lesson. Having resolved both those issues with a lot of labor, new bearings and a new magnetic ring, the engine won't start. Because the car didn't run much before the meltdown (1 tank of gas) I'm still working through the troubleshooting process of getting all the accessories sorted. While troubleshooting the "no fire" issue, I discovered that the bottom fuse in the stock fuse block was blown and, surprise, instantly blows any time I try to put one in. The #3 fuse is hot all the time to run clock, horn, headlights and interior lights (I'm thinking that short is the seat belt leads that I plugged into one another to complete the circuit since the new seat belts don't have the sensors- dumb idea.) From trying to understand Kimbrough's Spark-Fire and Spark-Run diagrams I don't think I need fuse #3 to make the engine run but I'm wondering if someone could shed some light on whether that's true or not and why I'm getting nothing. I've set the leading edge of the rotor to just where it would meet the #1 terminal in the distributor and then rotated the distributor body various degrees both directions while attempting to start it and not one cylinder fires. Any thoughts would be appreciated. I've already eliminated the spark plug wires, coil and plugs as possible culprits.
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| Posted: 12-09-2018 07:09 am |
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2nd Post |
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Frank Schwartz Member
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Fuse 3 feeds the clock, the dip switch on the light switch the right hand door light switch and the fasten seat belt light, which is also on #8 of the crazy buzzer unit, also #4 non the buzzer unit which is part of the seat belt circuit....As for your seat switches, I suggest since you are not using them that you just tape any exposed ends and leave them unattached and stowed under the carpet. If your buzzer unit is still in the car and you are not using it for the seat belt light and seat circuit, you should remove the plug from it and jumper #11 and #12..this will enable starting..if these are not jumpered your car will never start. Have you removed this plug already? To simplify matters since you are not using the seat belt circuits, remove the plug and jumper 11 and `12 on it.,..that should also stop the #3 fuse from blowing.... And #3 fuse will not effect the starting, but if you unplug that plug on the buzzer unit, it will most likely stop the fuse from blowing...but remember 11 to 12 on the plug...essential to start... Give it a try and let us know, please. Frank
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| Posted: 12-10-2018 02:55 am |
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3rd Post |
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redracer Member
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From many vehicles I have seen blowing the #3(bottom) fuse, it almost always has been the cigarette lighter, where the purple(hot) wire is grounding on the casing. Remove the 2, #2 cross point screws from the rear of the center console, unscrew the shift knob and loosen the tie-around string, and from the passenger side slightly lift the console to expose the 3 wires for the cigarette lighter(purple, black{ground} and red{light for night time). Using a VOM, check to see of the center post(purple) is grounding somewhere to the casing. Best of luck, bruce
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| Posted: 12-10-2018 07:07 am |
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4th Post |
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Frank Schwartz Member
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Bruce is right...the wire to the cigarette lighter is hot and if shorted out, the #3 will blow every time... Frank
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| Posted: 12-11-2018 01:42 am |
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5th Post |
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TanDJensen Member
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Frank, Thanks for the info, I'll trace those things down and let you know what comes of it. Much appreciated, Todd
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| Posted: 12-27-2018 07:22 pm |
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6th Post |
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TanDJensen Member
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Frank, I greatly appreciate your input about removing the seat belt buzzer- having read your suggestion in more than one post regarding "jumping #11 and #12"- but please help me understand what those numbers refer to. The JH wiring diagram doesn't show an 11 or 12 and neither does Kimbrough's, unless you mean his diagram Sections 11 and 12... Do you mean jumping (connecting) the two wires left dangling by the removal of the buzzer? Thanks.
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| Posted: 12-27-2018 07:49 pm |
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7th Post |
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Frank Schwartz Member
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If you will look at the very center of your diagram at the top you will see a square drawing with twelve numbered contacts. This is the seat belt control box as they call it..we merely refer to it as the buzzer. Removing it as it is no longer being used as a seat belt buzzer and all that jazz...it is necessary to take the plug that was plugged into this box and put a wire jumper between the number 11 and number 12 sockets where it plugged into the control box. This connection of 11 to 12 enables the engine to run. Without that jumper, you are " dead in the water" as we sailor used to say. In simplistic form: When all the seat belt wires are tied off, then the buzzer unit is useless, and when removing it, however, that jumper from 11 to 12 on the plug, not the unit, is required. OK???
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| Posted: 12-27-2018 07:57 pm |
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8th Post |
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Frank Schwartz Member
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Oh, oh...I just see you used Kimbroughs diagrams,....they are good, but not the JH supplied diagram... and not the one I use. Still, just take that plug and jumper 11 to 12 and you are good to go. If you do not have the "official" diagram...I have one that is blown up quite large and I can get a copy for a few bucks made at Staples for you...will need your mailing address...I think this will be of great help to you. Frank
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| Posted: 12-28-2018 12:18 am |
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9th Post |
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redracer Member
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what Frank is referring to is the round white(later ones were black)"LOGIC BOX" plug right about where your left knee would be. The numbers are "raised" on the round plug itself and may be difficult to see without sufficient light. After "jumping"/shorting #11 to #12, the car will be able to start(but has nothing to do with the car staying running afterwards)
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| Posted: 12-29-2018 03:12 am |
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10th Post |
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TanDJensen Member
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Frank and Redracer, I have the JH schematic from Delta, but figuring searching the car was a practical way of finding what you're talking about today I did locate the buzzer and the round plug you describe, so I'll install the jumper tomorrow. I have the 3 new 6-fuse blocks installed and wired in to the driver's side engine compartment fender well. I've fused 11 circuits thus far, adding 1 circuit to the #3 "always hot" fuse block for the electric radiator fan with thermostatic relay, and an additional circuit to the #2 switched fuse block for an Accusump pre-oiler (I added a simple toggle on/off switch beside the panel light switch to the left of the steering wheel.) I notice from the Delta schematic and from looking at the original fuse block that there is a hard copper connection between the #1 and #2 feed lugs. I think this is for the hazard lights which according to the nomenclature reads 46 amp. Please correct me if I'm wrong on this. I've converted every light bulb in the entire car to LED. I'm assuming because of the drastically lower power draw of the LED's that this hard jumper is no longer necessary. Any thoughts on this, and if it is necessary, any suggestions on how and where to make the jump. I would guess at the input lugs...
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| Posted: 12-29-2018 03:18 am |
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11th Post |
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Frank Schwartz Member
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AFIK the jumper between the two white feed wires is necessary. They are the feed wires for fuse 1 and 2...keep them joined. Frank
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| Posted: 01-26-2019 02:11 am |
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12th Post |
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TanDJensen Member
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It turns out the PO had already jumpered #11 and #12. I discovered in tearing apart the console in search of anything that looked wrong that the ground wire to the radio/electric antenna had pulled out of it's ground ring. Setting that right and replacing the stock fuse block seems to have cured all of the ca'rs electrical problems. Amazing what double-checking your work can reveal: short answer- keep your daytime job! Thank you to all for your help and encouragement. This car is phenomenal!
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| Posted: 01-26-2019 02:16 am |
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13th Post |
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TanDJensen Member
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Frank, I came to the same conclusion on the jumper between fuse #1 and #2 and so wired it as originally done.
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