No or weak spark help?

[robw13]

Right now ive got a weak battery to use and dont know if its the cause of my problems. The battery under load is 10-10.5 & 12.5 charged. The engine cranks but wont fire. Ive changed the coil, v.regulator, wires n plugs. The cap & button look good too. pour fuel down carb and no go. any suggestions much appreciated.

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I also changed the Dual Ballistor, Starter & Relay.

 

[bigmanjbmopar]

Replace battery. Then call us lol.

 

[robw13]

Figured that, but can u still get spark out of a weak battery?

 

[bigmanjbmopar]

We'll pull a plug wire or whole plug attached to wire hold it to metal of block and crank, if you see a spark you'll know it's not an ignition issue. Or if spark is weak you will barely see it.

 

[robw13]

ok, if by chance i get a new battery and see no spark, then what?

 

[bigmanjbmopar]

Then power trace from batt all the way through the ignition system until you find the bad part, typically newer voltage regs go bad but you should still be able to get a spark going. You sure ing switch is good? Starter relay good? Neutral safety switch good? All beginnings of ignition circuit. Checked all fuses?

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Go to mymopar.com for wiring diagrams

 

[robw13]

checked fuses under dash -good, relay & regulator are new. car cranks in p or n only. power trace with a multimeter or probe?

 

[ChargerRTguy]

I would get yourself a spark plug tester. They are not expensive, it plugs into the wire and the other end to the plug itself. You can even adjust the spark gap. It sure helped me out. With a multimeter, you can test for voltage at the coil, going to the distributor etc.

 

[Ron 73]

Bigman is right, You say your dealing with a weak battery, that is not a good thing with these cars, first you have to establish you have spark, and then move on. and it will only turn over in P or N. Don't get discouraged, takes time and going over each step and you'll get it!

 

[Dako]

Sounds like you may have a battery with a bad cell. Will it charge using a battery charger, but does not do a good job of spinning the motor over? If that's the case, even jumping from another battery may not get it started (had this very problem with my John Deere). Do you have another battery you can swap in for trouble shooting? That would be an easy (free) test. If it fires, you are done except for hitting the parts store! OR(!)...or, take your current battery down to said parts store and get it load tested (again...free). Nothing worse than replacing other parts for no reason.

 

[robw13]

Would a bad ICM cause No Spark? The back of this old one is disintegrated and leaking, u can the see the insides. Already replaced Distr. CAP & Button, Wires n Plugs, Relay, Volt. Regulator, Starter and Dual Ballistor. The ecu is a 5-pin, can I use the 4-pin that all the stores have now?

 

[daytona71]

Rob
You have replaced everything except the ICM. I think that maybe the cause of your problem. If the ICM is bad, it wont process the signal from the distributor telling the primary side of the coil to shutdown which creates the high secondary side voltage to fire the spark plugs.

Also the new 4 pin module replaces the 5 pin, just change ballast resistor to a 2 pin unit. check this drawing from mymopar.com
http://www.mymopar.com/downloads/Ignition_System_4pin.jpg

 

[robw13]

K just checkin, out of curiosity what does the fusible links look like at the bulkhead connector? Also, on the fuse block under the dash, there's 1 fuse/connector missing at the bottom labeled "battery/alternator" and don't see anything goin to it.

 

[daytona71]

This may not be exact for your car, but the link looks like this blue wire:

 

[robw13]

That looks similar and a lot nicer than mine. I dont think mine has any wires with fuses.

 

[robw13]

When usibg the 4 pin, which ends on the dual plugs do u use?

 

[robw13]

K, little stressed now. I've replaced bout everything and still no spark. Any ideas? Fuses under dash good except a connector is missing, the bottom of the fuse panel labeled batt/alt.

 

[Bruzilla]

Try popping the distributor cap off and cranking the engine to see if your rotor is turning. You could have a bad distributor, cam, or fuel pump causing the problem if the rotor doesn't turn.

If the rotor turns, put the cap back on and run a wire from the positive battery terminal to the positive post of the coil and crank the engine. If it starts, you can narrow the problem to something from the coil back. If not then you probably have a bad coil or more likely a serious timing issue, or a fuel issue.

 

[robw13]

I've used a spark test and no spark, as well pulling a plug and checkin, again no spark.

 

[bigmanjbmopar]

Ok no spark at the plugs with a fully charged battery right? Is your set up all oem stock parts? or upgraded electronic ignition? got pictures?