Pertronix Low Voltage Issue

In response to your questions George,

The hot wire which attaches to the + terminal of the coil is black. I

I measured the resistance across the terminals of the coil and got 1.0 ohm.

Thanks for your interest and expertise!

Don

Not sure what coil you have but the Petronix site suggests the Ignitor II works best with the Flame-Thrower II super low resistance (0.6 ohms) 45,000 volt coil.

http://www.pertronix.com/prod/ig/flame/coils/40000_volt.aspx

So perhaps you have that FT II coil? If not, what coil do you have?

Can you describe where you made this measurement (i.e. where the leads were connected).

I put Pertonix on my Feb 1968 E with inductive tach probably 16 years ago now and have had no problems with running or tach readings. The red Pertonix wire / and brown with white stripe plastic covered wire / and one cloth covered wire that I cannot determine color of any more / all to the SW marked side of the coil. There is a plastic covered wire with a white stripe coming out of the same two wire bundle as the cloth covered wire but that plastic covered wire is now not connected to anything. The black Pertonix wire is the only one on the other coil terminal. Not sure if this might help or not

David
68 E-type FHC

Your situation is very unusual! Why didn’t you have similar problems with the old points system? Why did it only show up when you converted to Pertronix. I will definitely do some searching to see if I have something similar but first I need to change my plug wires. You probably installed the original Igniter setup. I purchased an Igniter 2 system in which case Pertronix states quite unequivocally that the old plug wires must be replaced with emi shielded cables otherwise the igniter will be affected. Someone told me that it wouldn’t matter if I used the old cables but I’ll soon find out since I just received a new set. I will update the forum as soon I get the problem resolved.

Thanks for your interest and help, much appreciated!

Yes , I did purchase the Igniter 2 and a Flamethrower coil. I was told that the Igniter2 would likely work with my old cables but from what Pertronix says ,that is not the case. Pertronix clearly says that the plug wires must be upgraded to avoid emi interference. I have just received a new set and plan to install them in the next few days . Hope this will fix my problem!

To answer your question about how I measured the 10volts, I attached the + lead of my Voltmeter to the + terminal of the coil . The - lead was grounded to the engine. Turned the ignition on and checked the voltage.

Not to beat a dead horse, but why when you ran a home run to the battery it ran fine?
I’m all in from 30 years ago with fiber optic wire as the copper spark plug leads would melt, but I still think theres a home run issue here.
gtjoey1314 good luck

I think that indicates a problem you will need to address (and accounts for why your running issues cleared when you ran a wire directly from the battery to the coil).

I have the red wire from the Pertronix on the + terminal of the coil and also a black wire which goes to the ignition switch. On the - terminal of the coil, I only have the black wire from the Pertronix . I have one wire, yellow with a black stripe that is not connected.

As I’ve mentioned to a few other forum members, and I don’t know if this makes any difference , I’m installing an Igniter 2 system with a Flamethrower coil. According to Pertronix ,you must use shielded plug wires with the Igniter 2, otherwise the module will be affected by emi coming through the old plug wires. I have now received a new set of plug wires and plan to install them in the next few days so will see if this fixes the issue.

Wheres the two volts…a new book like WHERES WALDO…
Unless someone put a reducer or surpressor in the line, run a new line as temp from key to coil
Does anyone here ever had a BLACK wire for a lead.
I think we are on to something like a splice connection.
just my 1/2 a cent.
gtjoey1314

That’s a good question and one that I’ve thought of too. Will find out when I change the plug wires. I may have mentioned that I ran a wire directly from the + terminal of the coil back to an open terminal on the ignition switch but it didn’t run well. However in that case I wasn’t sure if the wire gauge was sufficient.

Yes , I agree. When I ran that test the voltmeter did not immediately show 10 volts it took maybe 15-20 seconds to get there …?

I did run a new line from the coil to an open terminal on the ignition switch but it didn’t run well then either.

That suggests you have a voltage drop between the battery and the ignition switch.
Try a new connection from the battery to the ignition switch input terminal. It can be run through the door to the drop-down panel. Have you installed the new plug leads yet? Pertronix website insists that these are required.

I checked the voltage at the coil and only got 10 Volts so yes I agree there appears to be a voltage drop issue. The strange part is that I had the Pertronix installed at a local garage and drove the car home without any issue. When the mechanic road tested the car he said he had it up to 100mph and although the tach got a little wonky around 4000 rpm he said it ran fine. A few days later I took the car out, turned on the headlights and it quit. I re-started it and tried turning the lights on again while driving and again it quit. I got the car home,parked it and since then it has been undriveable due to rough running and misfires. Will be visiting the mechanic tomorrow to understand if he simply installed the Pertronix as per the instructions or had to make changes to the car wiring to get it to work. Will be installing the new plug wires in the next few days . As you mentioned Pertronix is very clear on the need for installing new emi cables.

I think I may have finally resolved the Pertronix issue. Haven’t road tested it yet but will do so tomorrow.
Changed my spark plug cables to emi shielded ones and found the old cable going to the front plug in very poor condition. In the process of installing the new cables I removed the plug socket on cylinder 1 and the ceramic insulator on the plug came with it . When I had the Pertronix installed at a local garage, I asked them to do a compression test on the car since in the 15 years I have owned it I had never had one done. So it would appear that in the process of performing the compression test they cracked the spark plug .
I have yet to dress the spark plug cables but need to know if I can temporarily remove two of the chrome dome nuts that hold the head down and if so what do they need to be re-torqued to? Two of the dome nuts hold brackets that secure a length of “conduit” which the old plug wires ran in. I want to clean up the cables and re-use the “conduit” to maintain the original look as much as possible!
Thanks to all of you for your interest and support! Your suggestions and ideas were very helpful and much appreciated as always!
Don

I do not think there is any problem with undoing those nuts to remove the plug wire conduit - well anyway I did it and had no problems.

Yes, torque them upon reassembly. Torque is in the manual - pretty sure I recall it but don’t like to quote important numbers from memory.

Don,

In principle this shouldn’t be an issue. However, there are risks. If you have a long stud block (you can check in several ways including counting the freeze plugs), it’s been known for a corroded stud to snap when trying to undo the nut. Suddenly you are deep in the mire. That’s why I’ve left well alone and not fitted the conduit. YMMV…

-David

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Thanks for your advice …I agree, not worth the risk!

Don

Thanks for the reply George!

Don

The thing I did was to remove the rivets that hold the conduit to the brackets. This way I did not have to mess around with the head nuts to still have the conduit in place. I think the wires hooked up to the plugs secure it just fine. You have to look close to tell it is not “correct”. I think I could put in new pop rivets if I ever want to but so far is much easier to deal with plug wires without the brackets on the conduit.

David
68 E-type FHC