Author Topic: Starting problems  (Read 17199 times)

jdv69z

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Starting problems
« on: October 10, 2008, 01:43:55 AM »
I'm trying to  finish up replacing a clutch in my 69 Z. In the process of getting the clutch back in I pulled the motor, and now have everything re-installed.

In trying to fire the motor, it fires intermittently, but won't run. I removed the distributor when I pulled the motor, and have re-installed it. It is not timed exactly yet, but it should be close enough. Rotor is approx lined up with number 1 cylinder on dist cap when 1 is. at top dead center. Doubled checked with compression to make sure I'm not 360 off.

Distributor has pertronix ignition replacing points with black wire to coil negative, red wire to coil  positive. Ignition wires from car harness to coil positive. Condenser and tach send are on coil negative.

Nothing else has been removed or changed on the motor adjustment wise. Could this be the coil? I've always thought coil either worked or did not. It was workng fine when the motor was pulled, but could this be a weak spark? I'm in the process of installing new coil just to be sure.

I have also installed new plugs, thinking old ones might be fouled, but no improvement. Old plugs had 5 cylinders looking sooty black with 3 showing some brownish Nestles quick color like they were the only ones firing?

Pardon me if I'm missing something simple here.

Any ideas appreciated.

Jimmy V.
Jimmy V.

fireZ

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Re: Starting problems
« Reply #1 on: October 10, 2008, 12:05:45 PM »
When I put pertronix in one of my cars I had to buy the pertronic coil also.No problem since then.
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dutch

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Re: Starting problems
« Reply #2 on: October 10, 2008, 03:04:34 PM »
  Depending on the Pertronix version you may not be getting sufficient voltage at the module. Some versions require that you add a resistor or at least use the old resistor wire already in place for the original points set up to lower the voltage to 8 or so volts - the later Pertronox versions need or want to see full voltage without any resistor in the circuit.
  Not sure if this would make it impossible to work at all with too low a voltage of 8 or 9, bit it certainly could go a long way to make it run poorly for sure. Check the Pertronix unit you have to see what it calls for in the way of voltage to see if maybe this could part or all of your problem.
  I too added a Pertronix coil just to insure that everything went together since some coils have a resistor built into them to work with points setups and would lower the output to the Pertronix module so I reasoned that the Pertronix coil would obviously work with their own stuff better than other brands might. - Randy

jdv69z

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Re: Starting problems
« Reply #3 on: October 10, 2008, 03:16:04 PM »
The coil I am installing is a Pertronix unit so we'll see if it solves the problem. Car was running just fine however, with the previous coil until I pulled the motor etc; Maybe old coil was damaged somehow during the process? If new coil solves problem, then I'll be happy. I'll update when I get a chance to try it. I was just looking for feedback in case there was something I was totally overlooking.

Jimmy V.
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JohnZ

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Re: Starting problems
« Reply #4 on: October 10, 2008, 04:13:52 PM »
The Pertronix module (red wire) wants a FULL 12 VOLTS, and it's not getting it if you have the red wire connected to the coil (+) terminal if you're using the car's original ignition wire to the coil - that wire is a resistance wire, and serves the same purpose as the ballast resistor did on earlier cars - it reduces the coil feed voltage to 7-8 volts to protect the points. You need a straight 12V ignition-switched feed for the red wire, directly from the fuse box.

If you're using a stock coil, it still needs resistance-reduced power to the (+) terminal, or it will fry; if you're using the new Pertronix "Flamethrower II" coil, it's designed to run at a full 12 volts.
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rich69rs

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Re: Starting problems
« Reply #5 on: October 10, 2008, 05:38:02 PM »
As JohnZ suggested, the Pertronix unit "wants" a 12 volt source; wiper motor is one possibility, straight off of the battery is another.

However, if everything else is in good shape, using the reduced "ballast" voltage shouldn't keep your car from running or starting.  If your car won't start and run, you probably have something else other than low primary voltage, unless your primary voltage is consistently dropping below 8 volts.

On both my 66 Chevelle as well as my 69 RS, I have made the conversion to the Pertronix Ignitor electronic ignition with their flame thrower coil and all works just fine with the resistance (ballast) wire in place.  According to Petronix, their electronics package is designed to operate between 8 and 16 volts.  In the stock setup, when the engine is running you do not have a full 12 volts at the coil +terminal due to the resistance wire being in the circuit.  Hence, JohnZ's recommendation to connect directly to a 12 volt source, which is a very good suggestion in that it ensures that you will always have enough primary voltage.  However, I have checked both of my cars and I have between 9 to 9.4 volts and both cars run just fine.  However, neither of my cars are performance rides, so neither car ever gets pushed very hard.



« Last Edit: October 10, 2008, 06:04:16 PM by rich69rs »
Richard Thomas
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jdv69z

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Re: Starting problems
« Reply #6 on: October 10, 2008, 06:53:09 PM »
Thanks for the info, it is much appreciated. I'll check to see what voltage I've got. If it's enough to fire the engine, I'll attempt to do that first, then once I've go that corrected, I'll see about a 12v feed. I'm hoping this is the issue, but I'm still not sure.

Jimmy V.
Jimmy V.

jdv69z

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Re: Starting problems
« Reply #7 on: October 11, 2008, 08:44:42 PM »
OK I'm looking at what I believe is the original resistor wire feeding the + side of the coil. Sort of looks yellow/goldish and insulation looks almost like cloth? There is also a black wire with it attached to the same connecting lug. What's this wire? Can I just remove these, insulate them from grounding, and run new 12V feed from the fuse box?

Jimmy V.
Jimmy V.

JohnZ

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Re: Starting problems
« Reply #8 on: October 12, 2008, 03:51:59 PM »
The multi-color cloth-insulated wire is the stock resistance wire feeding the coil. The other wire crimped to the same lug should be yellow - that's the bypass wire that feeds a full 12 volts to the coil from the "R" terminal on the starter solenoid when the starter is cranking.

Check the "IGN" cavity in the fuse block for power while cranking - if you have power there while cranking, that's where you want the feed to the Pertronix red wire to go. The other two stock wires currently on the coil (+) terminal need to stay there if you're using a stock-type coil so it gets "run" voltage (resistance wire) and "cranking" voltage (bypass wire).

If you have the new Pertronix "Flamethrower II" coil that runs on a full 12 volts, you can power it from the same red wire feed that runs the module, and you don't need the bypass wire (or the resistance wire) connected.

The diagram below shows how all three conditions (stock, Pertronix with stock coil, and Pertronix with 12-volt coil) are wired on a Corvette, which has an external resistor instead of the later resistance wire; with a stock coil, the resistor is still used to feed only the coil, and with the Pertronix 12-volt coil, the resistor is bypassed so the coil gets 12 volts.

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jdv69z

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Re: Starting problems
« Reply #9 on: October 12, 2008, 05:16:04 PM »
Makes sense, John. Thanks again for the help. I'll update when I finish. I'm hoping it's today.

Jimmy V.
Jimmy V.

sam

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Re: Starting problems
« Reply #10 on: October 12, 2008, 07:31:26 PM »
Jimmy, Just for the heck of it make sure your ignition wires are pushed tightly on the ignition switch. When you turn your key to on the car starts right up and when you let go of the key the car shuts off??  Just check and see if they are tight or whatever. Just a thought.  ???

jdv69z

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Re: Starting problems
« Reply #11 on: October 13, 2008, 02:35:59 PM »
Yes, thanks. I have installed the feed from the fuse box/ ignition to the coil, and am reading 12V at the coil. (I checked) Ready to try, just have too many activities to get to it. Like son's birthday party Saturday, Lego league yesterday, and cub scout pack meeting tonight. Hopefully I'll get the chance and she'll be running tomorrow night. I'll update Wed.

Jimmy V.
Jimmy V.

jdv69z

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Re: Starting problems
« Reply #12 on: October 16, 2008, 11:58:43 PM »
Finally tried to fire up the motor tonight with new Pertronix coil. No success. While cranking, it fires here and there, but  not enough to get running. Removed coil wire and grounded to motor to check for spark, and am getting one, but it is yellowish in color. Shouldn't it be more blue in color? I'm thinking still that I have a weak spark. Is this possible from the ignitor unit in the dist? Only thing I can think of now is to covert back to stock points/coil setup. Any other ideas?

Jimmy V.
Jimmy V.

tom

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Re: Starting problems
« Reply #13 on: October 17, 2008, 02:20:24 AM »
Have you checked your coil wire?
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rich69rs

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Re: Starting problems
« Reply #14 on: October 17, 2008, 02:25:43 PM »
Get someone to help and measure your primary voltage (+ terminal) on the coil when cranking - should be close to 12 volts.  If you have 12 volts on the primary side during cranking, then the cause of the "yellowish" spark is downstream of the primary + terminal lead connection.
Richard Thomas
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