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1947 Pontiac Streamliner No Spark


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Hey all new to the forum and currently working on a 47 Pontiac that has been sitting inside for the last 40 years, I’ve done new coil, new points, condenser, cap, wires, battery, plugs, even found a burnt out fuse under the dash connected to the ignition, I still have no spark to the plugs, am I grounding out in the distributor? Is there something I’m missing? Any help would be appreciated, straight 8 motor spins fine good compression in all cylinders this thing is relatively in amazing shape for sitting inside for so long

9BDB52A6-F648-496D-9CBC-11014A8F588F.jpeg

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Hi, two things.

Just because things are new, don’t assume that they work.

Just because things are old, don’t assume that they don’t work.

 

We often waste lots of money and time by replacing items which are perfectly good. Best thing to do is to try and test if a part does work or has failed before replacing it. Otherwise you end up replacing five things and never find the true cause of the problem.

 

Best to use a test light and a multimeter and check for voltage and grounds along the ignition circuit including the switch. You can always “hot wire” it to bypass some of the circuits too!

 

Just keep checking, they are simple circuits.

JMTBW Rodney 😀😀😀😀😀😀😀

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Test light shows power to the coil from ignition switch and then to the distributor and now the whole distributor lights up no mater what I’m touching , tried the jump wire and well it just gets really hot and smokes within like two seconds, need to use a larger gauge wire

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Sounds like the short ground lead on the points plate might be broken. Check the wire from the coil to the distributor is insulated where it connects to the distributor. You might be best to put back the old points and retry the testing. Distributor body should not be powered.

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3 hours ago, studeboy said:

I'd try a jumper wire from the battery to the distributor next. If it starts then you have problems with your switch or wiring to it.

That is a GROUND WIRE from the battery ground to distributor metal body. With the key on there should be battery voltage to the ignition side of the coil and 0 volts on the distributor side if the points are closed and battery voltage if the points are open.  

Edited by TerryB (see edit history)
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18 hours ago, Jbeav said:

Test light shows power to the coil from ignition switch and then to the distributor and now the whole distributor lights up no mater what I’m touching , tried the jump wire and well it just gets really hot and smokes within like two seconds, need to use a larger gauge wire

he misspoke. Dont jump power to the distributor, you will melt something.  power to the coil.

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This is why I always diagnose a problem first. You tried throwing parts at it, why not figure out what the problem is?

 

Start with a 6 volt test light or multi meter. With the key on are you getting power to the coil? Power to the points? Are the points opening and closing when the engine turns over? Is the point gap somewhere close to factory specs? With the test light clipped to the points and the other end grounded, does the light blink off and on as the points open and close? The points simply switch the current to the coil off and on, when the points open the coil is supposed to fire. If the ignition passes the above tests, your primary circuit is ok. Now attach a spark plug and plug wire to the coil. Make sure the plug is grounded, that means the metal part should be touching the head or some metal part of the engine. Do you get a spark when the engine turns over? If you get a fat white spark that is perfect, but even a yellow spark should fire the engine. If no spark you should suspect the spark plug,  coil, wire, or condenser.

 

If the coil is firing the next step is to install the rotor, distributor cap, plug wires, but leave the plugs lying on the head. Turn the engine over and they should all fire one after the other. If they do, your ignition is working and there are only 2 more things to check.

 

One is the timing. You can't always go by the timing marks on the front pulley but they may be all you have. So use them but double check by putting your thumb over the #1 plug hole. If it is coming up on compression you should feel a woosh of air as you turn over the engine to TDC. Then you know you are not 180 degrees out. Set the crankshaft by the timing marks, and slowly turn the distributor forward until the points just open. One way to do this is to use the 6V light, when the light goes out the points are open. Another way is to put a cigarette paper between the points and slowly turn the distributor, when the paper pulls free the points are open. Notice where the rotor points, that is your #1 plug wire location. Make sure the plug wires are in the proper firing order, it should be printed on the head, you can tell which way the distributor rotates by which way the vacuum advance pulls. They always pull the opposite to the direction of rotation.

 

OK now you should have spark, and they should be occurring in the right cylinder at the right time, at least close enough to start. If you get stuck at any point ask a specific question and we will try to find the answer.

Edited by Rusty_OToole (see edit history)
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On 11/19/2020 at 5:26 PM, studeboy said:

I'd try a jumper wire from the battery to the distributor next.

NO!

 

As said above, power goes to the coil. The other small coil terminal goes to the distributor points.

 

Yes the jumper wire as instructed to be installed will catch on fire!😲

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Even those free DVOMs from Harbor Freight are fine for troubleshooting a car! I haven't seen the free coupon for several years now, but they are cheap to purchase anyway. 

 

Fluke makes fine equipment, but not needed for most automotive work on antique cars. Can be used to compare with cheap meter to see how good the cheap meter is.😉 

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The above recommendations for testing are spot on EXCEPT do NOT connect power to the distributor!!  One other test that has not been mentioned is to test the ignition circuit to make sure there is not a bad connection or switch in that circuit. There are two ways to test that circuit. The first is with a test light. Disconnect the coil wire to the distributor cap. This is for safety while making the test. Connect the test light between the ignition terminal of the coil and ground. You should have a steady light when the ignition switch is turned on. Now turn the motor over manually and watch the test light. When the points close the light may dim SLIGHTLY, but it should still be on. If it goes out or gets dim you have a bad connection in the ignition circuit. If this is the case, leave the motor in the same position and start testing at each point where the ignition wire connects going back toward the battery. When you get a bright test light you have just moved past the problem. For example, you test back to the ignition switch. When testing the coil side you have a dim or no light. The next test point is the other side if the switch. When you test that point you get a bright, steady light. This tells you that either the ignition switch is bad OR the connection terminals are not making good connection. I think that gives you the idea of the test. The other way to test this is with a test meter measuring voltage. Follow the same procedure and if you find a significant voltage drop below battery voltage you have found the problem.

   One other thing I need to mention is that some ignition circuits have either a resistor or a resistance wire in the ignition circuit. I do not think any 6 volt systems have this resistor, but most 12 volt systems do. When doing the test on a 12 volt system, there will be a significant voltage increase on the battery side of this resistor. This is normal. If you are using a meter, the coil ignition voltage will be around 8 volts and the battery/switch side will be very close to battery voltage.

   This is a bit wordy, but it can really help determine the location of the problem with a simple set of tests. That will speed the repair and reduce frustrations!!!

 

Let us know what you find...

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Ok so here what I found out after buying a nice multimeter the original coil was not bad, and the coil I did order and receive after reading shop manual was made for a six cylinder engine, according to the shop manual they had specific coils for the six and eight cylinder engines, stated each coil had certain characteristics for each distributed and engine, that being said the ground wire was bad from coil to distributor after replacing still seemed low voltage to distributor but had good spark between the points and thus testing the spark plugs had good spark and fired in order, so lesson learned about just throwing new parts at it and thanks again everyone for your help 

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If there is a spark from the points, and the old points are burnt, it is a sign you need a new condenser. Old ones often fail, even NOS ones that have never been used but are more than 20 years old. New ones often come from China and are of suspect quality. I have thought of using a modern mylar or orange drop capacitor of the same value and 400 or 600 volt capacity, wired to the coil if it won't fit in the distributor. If the condenser is exactly right the points will not burn.

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