Good morning, Having some trouble figuring this first fire out on my 63.5 Falcon Sprint convertible v8260. What I have: -stock 260, 2 barrel full rebuild (dipped, bored, machined etc. no mods. All original set up, wiring etc.) - stock distributor rebuilt with points. What I have done - tdc, timing set 8-10 advance, dwell set with test light. - getting fuel - ignition components tested coil, points, condenser, got spark at boot when cranked Problem It wants to fire but won’t catch.. I am suspecting the on/run resistor wire. When I test the ignition wire to the coil and crank the ignition I get 12 volts (as I should when cranking), when the key goes back to the “on” position, my meter reads 0v With the stock resistor wire, shouldn’t I be getting 6volts when the key goes back to “on” after cranking?
Another thought, would wires switched on the Ford starter solenoid be the culprit? I ***ume switched wires here would make things goofy with cranking the engine…Maybe the voltage regulator? I am questioning everything at this point. Under the dash was left alone, engine compartment harnesses were minimally disconnected to repaint the engine compartment...
With key in run position, and points open, you should see voltage, probably not but something. But if you stop with the points closed there will be no reading. you can try a temporary jumper + post of the battery to the coil to see if it will run to eliminate that possibility or confirm it.
byp*** the resistor wire with a 14 ga. jumper wire and a 12v coil, you can use your coil but it will eat points if you don't resist it... balist resistor or wire. should tell you if the wire was ok...
If the points are open, then the voltage at the coil, key on, engine not running, would be 12v. With the points closed, it should drop to about 6v. The reason it will give 12v with the points open, is that it's a voltage divider, and the resistance of the meter is much higher than the resistance of the wire. Having some understanding of Ohm's and Kirchhoff's Laws will help you understand this. If you get no voltage at the coil, with the key on, then the resistor wire is not working properly--either it's broken, or disconnected.
Great explanation, I will check if the points are open or closed. Nonetheless last night it was 12v cranking but then 0v on the on position. Something is not right here… Will post what I find. Thanks for all the responses so far!
So I highlighted the schematic and started tracing and test. Everything was making sense until I got to the “s” wire or neutral safety switch wire. I got continuity on about 3 posts on the firewall harness(?). Isolated the S wire and then only got continuity on 1 post at the firewall plug… like it should be. The S post is actually grounding to the relay/solenoid bracket… I am pretty sure this is wrong…don’t have another to verify. It’s a repo solenoid by the way…
^^^ yep jump the coil it won't hurt anything for the short time it will take you to try and start it. The S terminal on the solenoid is power from the ign switch only in the start position(it engages the solenoid) The I terminal provides 12v to the coil while cranking(both of these circuits appear to be working for you)
Figured it out, the resistor wire was the culprit! Engine fired on first try. Still had 12 v on the on position, will need to check if points were open or closed as mentioned before. Still think I should replace the solenoid as I was getting that ground in the S post…
No. Solenoid is fine. Remember the S(tart) terminal is used to power the coil inside the starter relay. That coil is an electromagnet that pulls in the solenoid which then makes the contacts for the Starter terminal and I(gnition) terminal. Power comes from the battery up through the harness into the ignition switch as a constant hot. When you twist the key to START, power from the battery to the ignition switch then comes back down another wire to the S(tart) terminal and powers the solenoid. Coil in the solenoid can only function if it completes the circuit to ground. When the key is released from START position the contact inside the ignition switch breaks, this drops power from the S(tart) terminal and the solenoid drops out, which then breaks the contacts on the Starter terminal and I(gnition) terminal. If the S(tart) terminal was open to ground then the starter relay would never function and you would not be able to start the engine.
Might want to run a new wire to a block resister and do away with the resister wire. Almost every resister wire I've ever seen on an old car was burned up, and surrounded buy other wires in a harness.. Every old car I buy I always open up all the wiring harnesses and check out the condition of the wiring..
The Ford resistance ign wire , is usually good for the life of the car . Cutting into it or modifying it means trouble . Replace it with a block resistor or a new wire and drive it like you stole it !
Well… you asked so I will share lol when I got the car there was a black and red wire nutted to a 70’s underdash c***ette deck power wire. The day I got the car that thing was removed. To be sure, I connected the black and red wire and then drove the car some before I tore it apart. During sprucing up of the interior I went about checking all wires and connections. Everything was stock minus the c***ette deck thing so it looked good. The red wire was reconnected to the stock AM radio and the other black wire I was positive was an unused wire for the dome light plug (I have a convertible). Fast forward to last night I began tracing everything…I noticed the black wire actually led to a pink wire via bullet connection. Upon closer inspection I noticed the pink wire read “resistor wire do not splice”…eureka!…unplugged the black wire, removed the red wire off the ignition switch harness…tested continuity. Turned key to “on” and got 12v at the coil wire. Turned the key and it fired instantly…let it run for 10 seconds and shut it down as it was about 11:30 pm. Sorry for the long response but it shows how a previous owner’s small change change can throw you off and when in doubt check everything. Actually, before you start CHECK Everything lol. Luckily, they were too lazy to splice so I simply unplugged the two extensions and was able to plug the resistor wire right back into the switch harness as stock. I will replace that wire before I continue breaking in the engine.
Thanks Mike, your explanation makes sense. The thing is brand new so being faulty would be plausible but un likely
That’s what I thought… how can something like that god bad, however previous owner had the R-wire, ignition wire and the c***ette deck nutted together, maybe that toasted the resistor? Who knows but it appears I can unplug the wire and plug a new one right in. Probably the way I will go with it.
Last question here, I am running points now, if I want to upgrade to a petronix trigger and petronix coil, do they need to be reduced just like old points or do they take 12v cranking and on the “on/run” position? Just curious as I plan my resistor wire replacement. Thanks again!!
You can run the basic Pertronix I Ignitor and a 1.5 ohm ignition coil with straight battery voltage (no ballast resistor). Make sure you run the correct coil though, if you select a lower resistance coil the excessive current flow will burn up the trigger module.
Heat, the resistor wire can produce some low heat across the length causing the outer coating to get brittle and come off over time.
Ignitor is more of a points replacement unit. It can run off full battery voltage but is best suited as a simple points replacement. This is the unit known to burn up if left with Key On/Engine OFF. OR Ignitor II can run off resistor or full battery voltage, if you use the FlameThrower coil you can run both with full battery voltage. This is the unit that prevents burning up if the Key On/Engine Off. Improves overall starting and running of stock engines as well over the Ignitor. OR Ignitor III has the rev limiter and but may not be as durable as the other two and not compatible with older points style components, you will have to run a Flamethrower coil and full 12V. This is a good system if you're going for a sleeper look. OR If you don't mind a bit more work, use a Duraspark distributor ~'75-'85 Vacuum controlled timing, and a HEI ignition module mounted on a heat sink. You can maintain the early points cap or update to the large cap/rotor for better spark. This allows easier repair/replacement if the pickup or the module fail as these are still readily available from the parts store. Ignitor II is the easy ****on, and allows for easy swap to points if you have a failure or want to diagnose, or return to factory.
Okay, okay the Speedway thread about broken clutch/brake pedals is dead, "Long Live (or not) the Speedway Broken Clutch/Brake Pedals" thread. OK here's what happened. Somebody somewhere at some point before I bought the mounting hardware, did shorten and then weld/spotweld/attach the broken clutch/brake arm pedal mounting brackets back onto the shortened arms making it look like it was never messed with. But man, they did a good job of hiding their work. Apparently, after modifying it, they turned it into Speedway for a refund/return then some yokel at Speedway, because it didn't look messed with didn't compare the broken arms to others in stock and they then resold it to my dumb***. In my defense, I didn't compare the offending pieces to any other because I only had one to work with. I could not appreciate the skill that someone employed to deceive yahoos like me; neither a welder or mechanic am I. But I love all things mechanical and I work twice as hard as the guy with inherent mechanical skills. Anyway, when I compared the broken arms to the new unit Speedway sent, it was immediately obvious that they didn't match and indeed the broken pieces are about 2-3 inches shorter. So hats off to you guys for your knowledge and input. I just wanted to clear that up because I'm sure many of you were on the edge of your seat just waiting for a conclusion (for some it couldn't conclude soon enough) to this story . Next time I'll run it by you guys before I run off like a head with my chicken cut off claiming the sky is falling ! Thanks guys and gals. Hot rodding at 75 ain't for sissies !!
You clicked on the wrong thread, not sure why you felt the need to explain on this one. Start a new thread with your confession.
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