Slant Six Forum :: Pickup coil resistance

I've got the pertronix 3ohm like you have or had, and the mopar orange box ecu. The coil checks out + to - as getting full battery voltage, or very close to it. I removed the ballast resistor.

You need to verify that your cam timing has not jumped or been timed wrong.
Number one on compression at TDC, both valve rockers loose, closed, then move to the dizzy.
When number one is at tdc on compression, both valve rockers should be loose. In a perfect world the timing mark on the balancer should line up with the mark on the tab. And the rotor in the dizzy should point directly at number one plug. If any of these are off it won't fire. Bump the engine over with number one plug out and your finger in the plug hole. When you feel pressure push your finger out your near TDC on compression. Point the rotor to number one and you should be close enough to fire. While cranking the engine, slowly turn the dizzy back and forth till she fires.
If all of this does not work you have bigger problems.

After your nerves settle down, give a try again. You must have had a lot of fuel in the manifold.

Hopefully the needle and seat are ok and shutting off the fuel level. Sometimes that can be a sensitive adjustment do to the float being too high....

At least it is running!

Pulling the coil wire is best for emergency shutdown situations. Even with stock wiring pulling the battery connections off won't stop it. Some use that as a "test" to see if the alternator is working but it's not a good idea as it strains the alternator excessively.

Was the distributor bolted down? Most of the time it won't but if things are just right it will turn in place - if timing was changing on the fly like this then that explains the runaway... or a stuck throttle perhaps?

Author:	killnine [ Thu Jan 09, 2014 3:03 pm ]
Post subject:	Pickup coil resistance
I'm getting between 250-300 ohms resistance when I measure my electronic distributor pickup while spinning it by hand. I have a weak to no spark condition I'm trying to figure out, and this is a little out of spec from what I can tell. Is this too low? It does produce 1 V AC on the meter when I spin it, and every reluctor fin will beep when it spins and I meter continuity.

Author:	Aggressive Ted [ Thu Jan 09, 2014 3:08 pm ]
Post subject:
If your over 150 ohms your good to go! That's not your problem..... My guess you haven't grounded the ECU with a separate ground strap. Or the coil is not getting enough voltage because of the resistor, etc.... What does it show on the plus terminal? Hopefully your coil isn't leaking oil......that is when the go bad.

Author:	killnine [ Thu Jan 09, 2014 3:41 pm ]
Post subject:
I've got the pertronix 3ohm like you have or had, and the mopar orange box ecu. The coil checks out + to - as getting full battery voltage, or very close to it. I removed the ballast resistor. I bypassed the ignition too so the ignition should get full time voltage as soon as I plug the terminal on the battery at the moment. I'm basically going down the checklist right now, and so far it seems like the dizzy checks out.

Author:	mattelderca [ Thu Jan 09, 2014 6:54 pm ]
Post subject:
Far as I understand, you cannot run any coil type on a Mopar box without a ballast resistor. The Mopar box cannot handle the current control without the resistor. Replace the Mopar box and reinstall the resistor as a factory system would have it. Or go with an HEI setup.[/i]

Author:	killnine [ Thu Jan 09, 2014 6:55 pm ]
Post subject:	Got spark, but still no fire
Well, after taking apart the distributor and making one good one from two slightly different ones, I can guarantee I have spark coming from the coil wire. Whether or not it is sparking at the right time I have no idea but it does what it does. From the #1 plug wire I also see spark. The rotor is near #1 plug wire when the intake and exhaust valves are closed/compression stroke, verified by me many times. I also tested the 4 wires going to the ECU at the connector, and I have battery voltage at the 2 that should have it and I have @280-300 ohm resistance across the other 2, which matches what I have at the distributor pickup coil when unplugged. It still just cranks and cranks. It never fires until I put all kinds of too much gas into the carb and then it will chug and spit. I'm pretty sure this means that the timing is off, because I put so much gas into it that it's firing the vapors left behind from so much gas being in there. Now, my plugs are surely somewhat fouled with gas but I wouldn't think this would completely stop it from trying to fire. So, I tried turning the distributor cap all the way to the left, where it was almost all the way to the right before, and it still just cranked, but then all the sudden out of the blue it started and ran for like 4 seconds and died. And it ran correctly too. Tried to restart it and nothing. So by this time I was sure it was flooded anyhow so I just left it be for now. I'm starting to get to wits end. I know this has to be something simple. Since the timing should be right based on what I've checked, could it be the ECU is bad? If so, it would mean both my old aftermarket chrome box and my new mopar orange box are both bad. I haven't been able to test compression but I know this car ran not long ago and the #1 plug hole will blow your finger out with gusto.

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Pickup coil resistance https://www.slantsix.org/forum/viewtopic.php?t=54279	Page 1 of 2

Author:	mattelderca [ Thu Jan 09, 2014 7:08 pm ]
Post subject:
You need to verify that your cam timing has not jumped or been timed wrong. Number one on compression at TDC, both valve rockers loose, closed, then move to the dizzy. When number one is at tdc on compression, both valve rockers should be loose. In a perfect world the timing mark on the balancer should line up with the mark on the tab. And the rotor in the dizzy should point directly at number one plug. If any of these are off it won't fire. Bump the engine over with number one plug out and your finger in the plug hole. When you feel pressure push your finger out your near TDC on compression. Point the rotor to number one and you should be close enough to fire. While cranking the engine, slowly turn the dizzy back and forth till she fires. If all of this does not work you have bigger problems.

Author:	Aggressive Ted [ Thu Jan 09, 2014 7:21 pm ]
Post subject:
Quote: I've got the pertronix 3ohm like you have or had, and the mopar orange box ecu. The coil checks out + to - as getting full battery voltage, or very close to it. I removed the ballast resistor. Excellent! Yes I am running the same system the last 5 years with the same Pertronix 60,000 volt 3 ohm coil and MOPAR ECU. I also have the HEI right beside it.....so I can easily switch. You maybe just off a few degrees.....if it pops. I have done what mattelderca described many times and got SL6 engines running. You may have flooded it....check to see if the plugs are wet. Use a little ether to clean them up.....

Author:	killnine [ Thu Jan 09, 2014 7:31 pm ]
Post subject:
Quote: You need to verify that your cam timing has not jumped or been timed wrong. Number one on compression at TDC, both valve rockers loose, closed, then move to the dizzy. When number one is at tdc on compression, both valve rockers should be loose. In a perfect world the timing mark on the balancer should line up with the mark on the tab. And the rotor in the dizzy should point directly at number one plug. If any of these are off it won't fire. Bump the engine over with number one plug out and your finger in the plug hole. When you feel pressure push your finger out your near TDC on compression. Point the rotor to number one and you should be close enough to fire. While cranking the engine, slowly turn the dizzy back and forth till she fires. If all of this does not work you have bigger problems. Well, I've done this alot since I've been over it a million times, but I'm starting to think that what should be TDC and correct timing really isn't. I'm starting to think that maybe something was put together wrong internally when they put a new cam and chain in before I bought it. I also noticed when working on this before replacing the cap and rotors and before I had a lot of problems that the PO had the wires plugged into the cap to where #1 plug wire was pretty much where #4 is supposed to be. So basically he had it set like it needed way too much advance I think. It ran like that so I tried plugging the wires up like that, but it's acting weird now, so I'm going to get a set of sacrificial plugs since these are prob soaked by now and let it sit a while since it's surely flooded. This would kind of jive with how it almost started and ran when I had it turned all the way to the left. Moving those wires one over like that would just do that and more.

Author:	killnine [ Fri Jan 10, 2014 4:11 pm ]
Post subject:	WTF runaway engine!
Well, I got my wish, after letting it sit and dry out I fired it up, back on the correct firing order on the distributor, and it started on the first try, and ran pretty good. It might have had a miss or two but it ran well. I put the timing gun on it and adjusted it to around 8 degrees btdc. It smelled really rich, and so I was just about to shut it down and do some more tuning when it started idling higher and higher, and so I freaked out and shut it off, but my ignition runs off the battery directly, so I pulled the negative, and it kept going! I pulled the positive, and it kept going for a second and BANG! out the exhaust. Tons of black smoke out the back and I saw fire shoot out the exhaust manifold heater flap area. Now this sort of thing has never happened to me. My heart is still racing!

Author:	Aggressive Ted [ Fri Jan 10, 2014 5:57 pm ]
Post subject:
After your nerves settle down, give a try again. You must have had a lot of fuel in the manifold. Hopefully the needle and seat are ok and shutting off the fuel level. Sometimes that can be a sensitive adjustment do to the float being too high.... At least it is running!

Author:	killnine [ Fri Jan 10, 2014 7:25 pm ]
Post subject:
Quote: After your nerves settle down, give a try again. You must have had a lot of fuel in the manifold. Hopefully the needle and seat are ok and shutting off the fuel level. Sometimes that can be a sensitive adjustment do to the float being too high.... At least it is running! OK, after thinking for a minute, I think I know what half of the problem was. Since I didn't put an actual switch in yet, the wires/fusible links coming from the alternator output were connected to the starter relay post that the battery also connects to. The wire I wired in to go straight to the ignitionand VR and coil I wired up to the + battery terminal. So even with the terminal disconnected and no battery power, the alternator output is still conducting to the ignition, meaning the alternator was feeding the ignition. So in other words my plan to use unplugging the terminal as an ignition switch failed miserably. Time to put in a real switch. I still have no idea what caused the idle to climb higher and higher until all hell broke loose, but that's probably something I can troubleshoot once I make sure I can shut it off

Author:	Pierre [ Fri Jan 10, 2014 8:43 pm ]
Post subject:
Pulling the coil wire is best for emergency shutdown situations. Even with stock wiring pulling the battery connections off won't stop it. Some use that as a "test" to see if the alternator is working but it's not a good idea as it strains the alternator excessively. Was the distributor bolted down? Most of the time it won't but if things are just right it will turn in place - if timing was changing on the fly like this then that explains the runaway... or a stuck throttle perhaps?

Author:	killnine [ Fri Jan 10, 2014 9:33 pm ]
Post subject:
Quote: Pulling the coil wire is best for emergency shutdown situations. Even with stock wiring pulling the battery connections off won't stop it. Some use that as a "test" to see if the alternator is working but it's not a good idea as it strains the alternator excessively. Was the distributor bolted down? Most of the time it won't but if things are just right it will turn in place - if timing was changing on the fly like this then that explains the runaway... or a stuck throttle perhaps? Yeah that's for sure. My plan didn't quite work out, as I thought I had wired it up so that when I pulled the terminal off the battery my directly wired ignition would cut out, but I just ended up making it just like stock because I wasn't thinking straight. Yeah it must be either the distributor cap was doing something weird or more likely the carb was getting more and more gas, or something like that. I'll check it out tomorrow. I'm thinking something is sticking, since it was fine for a few minutes.

Author:	killnine [ Sun Jan 12, 2014 12:04 pm ]
Post subject:
I wired up the ignition switch the way I should have to begin with, so I can shut it off properly. I tried to start it but it just cranks and doesn't fire. I took the plugs out to see what was up, and most of them are light brown/tan, and a couple are a little more black but not too bad. #5 and #6 however had a bunch of very fine grey particles, like a graphite paste almost. Almost like the stuff you can buy to dump in a bad radiator to seal the holes, but even finer. This can't be good. Why me. Le sigh.

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Author:	killnine [ Sun Jan 12, 2014 12:49 pm ]
Post subject:
Well, still not getting spark now. One step forward 3 back I guess. I tested the pertronix and it isn't giving a reading on the secondary resistance. I would expect 10k or so, but I get nothing on the meter. I took the old red can coil out and checked it and it reads nothing either. I think I'm going insane, or both my coils are blown.