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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Johno on November 10, 2008, 05:16:57 pm

Title: No Spark
Post by: Johno on November 10, 2008, 05:16:57 pm

78c20 350. I have  replaced pickup coil,coil,and module.I am getting 12volts at bat. terminal,8.5 when cranking,12volts at tach with ignition on. With cap flipped over wires still attached spark tester hooked to center button no spark. I have tried different coils,and modules but no luck.ANY IDEAS!

Title: Re: No Spark
Post by: VileZambonie on November 10, 2008, 05:30:11 pm

Check to make sure your coil is wired up correctly

Title: Re: No Spark
Post by: Lt.Del on November 10, 2008, 08:00:34 pm

Are you sure the distributor is spinning when you are cranking the engine?  This will tell you if the timing chain has broken.  No turn, broke chain.

If distr does spin, as Vile stated, check coil wires.  Ensure all connectors/connections are correct.  How old is the rotor?

There is a ground wire that attaches to one of the four coil bolts..ensure that wire is attached.

Title: Re: No Spark
Post by: Johno on November 10, 2008, 09:18:18 pm

Coil has ground bar,wired correctly,new rotor and cap.The rotor is turning.Motor was just put in in 2 months ago.It ran fine until 3 weeks ago idle was all over the place i though the choke was messing up then it just quit.Pulled fuel line and it was getting gas,pulled spark plug wire to check for spark none.I got a Pertronix tuneup kit,cap,rotor,module,coil and changed every thing  still no spark.Pulled distributor and replaced pickup coil still no spark.Tried different cap,rotor,module,coil no luck

Title: Re: No Spark
Post by: VileZambonie on November 11, 2008, 05:02:18 am

Check the pick up coil and pole piece. Measure the resistance and check to make sure the pick up coil isn't grounded. If ok check the coil and the module. It's one of the three if everything is installed correctly.

Title: Re: No Spark
Post by: gmtech2 on November 11, 2008, 08:09:56 am

check your pickup coil with a DVOM should have between 300 and at least 500 millivolts when cranking also check the plunger that goes through the cap from the bottom side of the coil make sure you have a little spring and plunger and a rubber spacer make sure they are in the correct order

Title: Re: No Spark
Post by: Johno on November 16, 2008, 02:51:47 pm

Thanks guys i swapped distributors still no spark.Tried 3 different coils no luck.I guess i have her towed to the shop

Title: Re: No Spark
Post by: VileZambonie on November 16, 2008, 02:55:37 pm

You have B+ even while cranking at the B+ terminal on the cap? You are sure the distributor is turning?

Title: Re: No Spark
Post by: DnStClr on November 17, 2008, 04:47:54 pm

Yeah .you'e done a lot of work without finding the problem Johno. Did you do what sgt. Del said- check the timing chain?

Title: Re: No Spark
Post by: Johno on November 22, 2008, 02:34:54 pm

The timing chain is good.Got it going,different distributor,module,and 1rst coil.Its hard to believe new parts are bad right out of the box.Thanks guys.